Kyōiku kanji (教育漢字, literally "education kanji"), also known as Gakunenbetsu kanji haitōhyō (学年別漢字配当表, literally "list of kanji by school year") is a list of 1,026 kanji and associated readings developed and maintained by the Japanese Ministry of Education that prescribes which kanji, and which readings of kanji, Japanese students should learn from first grade to the sixth grade (elementary school). Although the list is designed for Japanese students, it can also be used as a sequence of learning characters by non-native speakers as a means of focusing on the most commonly used kanji. Kyōiku kanji is a subset of Jōyō kanji.
Life on Earth has evolved in a form suitable for the gravitational force. Although the pivotal role of gravity in gene expression has been suggested, the molecular details remain unclear. Here, we show that mitochondria utilize gravity to activate protein synthesis within the organelle. Genome-wide ribosome profiling reveals reduced mitochondrial translation in mammalian cells and Caenorhabditis elegans under microgravity. We found that attenuation of cell adhesion through laminin-integrin interactions caused the phenotype. Mitochondrial translation is activated by a signal relayed by FAK, RAC1, PAK1, BAD, and Bcl-2 family proteins in the cytosol, and the mitochondrial fatty acid synthesis (mtFAS) pathway in the matrix. Consumption of mitochondrial malonyl-CoA by mtFAS reduces the malonylation of the translational machinery and accelerates the rates of translational initiation and elongation. Physiologically, this system operates in mechano-response of skeletal muscles. Our work provides mechanistic insights into how cells convert gravitational and mechanical forces into translation in mitochondria.
For high-temperature superconducting wires to be of practical use in large magnets, such as fusion magnets, they must be able to tolerate localized degradation. As a fundamental study, the thermal runaway behavior of REBCO coils was investigated with locally damaged coils immersed in liquid nitrogen and liquid hydrogen. The critical current, IC of the damaged part was less than 10% of the original value, and only one thin side of the REBCO tape was cooled with the cryogen. In the case that the tape was wrapped with 0.025 mm thick insulating tape (Kapton), thermal runaway occurred within the nucleate boiling region before the normal zone expanded. As the temperature rose, current in the copper stabilizer increased due to a decrease in IC, and the copper resistivity increased. The thermal runaway occurred at a temperature where the temperature dependence of the heat generation became stronger than that of the cooling power. In the case that the insulating tape was removed from the cooling surface, thermal runaway did not occur until the transition from nucleate boiling to film boiling. Under these conditions, the thermal runaway current in liquid hydrogen increased with pressure from 20 K at atmospheric pressure to 27 K at 0.54 MPa, despite the temperature rise. It is estimated that the critical heat flux increased with pressure. Since even a thin insulating layer significantly affects the temperature rise of the conductor, direct cooling of bare surfaces is preferable for good cryostability.
Detecting seismic activity on Saturn's icy moon Titan during the Dragonfly mission could provide crucial information on its internal structure. The geological complexity of the moon's surface suggests significant cyclic tidal deformation, likely leading to the fracturing of the ice shell. Considering realistic source locations and fault geometries, we assess whether a vertical short-period seismometer can detect body waves from a 4.0 icequake. Signal-to-noise ratios are evaluated by comparing the high-frequency content with the expected background noise and instrument capabilities for several ice attenuation scenarios and 1D interior models. Our results indicate that the high-frequency content (Hz) of tidal-induced icequakes is likely undetectable under the most unfavorable attenuation scenarios and atmospheric conditions. However, seismic signals in the 0.5-1 Hz band-where P wave reflections dominate-may still be observable for events occurring in potential seismically active regions at similar to 800-1,000 km from the Dragonfly's landing site. These signals could provide constraints on the thickness of Titan's outer ice shell, provided that intrinsic attenuation is low and environmental conditions are favorable.
Near-Earth asteroids (NEAs) are small, airless bodies that orbit in near-Earth space. Recent studies suggest that their surface rocks can undergo crack growth and fragmentation through thermal fatigue induced by diurnal temperature cycling. This process may expose materials yet to be altered by solar wind irradiation and micrometeorite impacts, known as surface rejuvenation. However, the mechanism that generates the initial cracks required to trigger thermal fatigue fragmentation remains poorly understood despite its importance for understanding the geophysical evolution of asteroids. Here we use numerical approaches to show that stony, or S-complex NEAs, the most compositionally common group, can experience rapid temperature changes, or thermal shocks, sufficient to generate microcracks in surface rocks as they pass through the shadow of a terrestrial planet. Our statistical analysis of backward orbital integrations demonstrates that these asteroids pass through planetary shadows more often than they encounter planets closely enough for planetary tides to rejuvenate their surfaces. We also found that shadow passages are shorter than typical asteroid spin periods, indicating that expansion stress from rapid heating occurs immediately after contraction stress from rapid cooling. These results suggest that thermal shock caused by planetary shadows may help trigger the surface rejuvenation of stony NEAs. Stony near-Earth asteroids may undergo fragmentation of surface rocks triggered by thermal shocks as they pass through the shadows of terrestrial planets, leading to surface rejuvenation, according to orbital simulations and thermophysical modelling.
This paper proposes a method for constructing physically reasonable multiple sensitive volumes and predicting upset cross sections in particle transport Monte Carlo simulations. The validity of method is discussed with the proton-induced single event upsets on several SRAMs. All simulated cross sections for proton energies from 0.7 to 230 MeV, except for a few data points, agreed with the experimental data within a factor of 0.3 to 3.
