Food acquisition by us Homo sapiens began with prehistoric hunter-gatherer. The food at that time must have been far from modern satiety. There are some major milestones in the history of food acquisition since then. Agricultural inventions, climate disasters, crop pathogens, democracy, market economy, industrial revolution, war, all have had a tremendous impact on our food. We have been short of food many times in history and have overcome it each time. The "Green Revolution" in 1960s was one of the greatest technological innovations ever. We are still able to acquire food this way. But now, the benefits of the Green Revolution are gradually diminishing, with today's world hungry population exceeding 800 million. We are facing new risks of our time: population growth, agricultural soil destruction and global warming. We need the "Green Revolution" again. As the attempt, molecular breeding by genetic recombination is being promoted immediately. However, it is calculated that this method will not be in time for population growth at all. I decided to address this issue with a new fertilizer that supplies silicate to the crops.

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[in Japanese]

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Heterotyly is the genetic polymorphism which consists of two （distyly）or three （tristyly）different morphs of flowers in the population. The flowers usually require the pollen from the different morph to set seeds, so that heterostylous plants dependent on suitable pollinators to reproduce. Numerous studies have been published on the biology of heterostyly since Charles Darwin’s book “The different forms of flowers on plants of the same species”in 1877, however there are still so many issues remain unsolved. In this article, I reviewed the studies on heterostyly of plants native to Japan. I also showed that future studies related to the fitness, maintenance, and the evolutionary breakdown of heterostyly.

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In this study, two discussions on the planforms of forward-swept wings for a 220-seat class aircraft are conducted. The two discussions are related with a parametric study of the wing planforms and an aerodynamic optimization with genetic algorithm. Both of the studies result in similar aerodynamic performances and geometries. As for the geometries, the longer semispan length leads directly to a better aerodynamic performance. On the other hand, the changes in the inner/outer swept-forward angles and the chord length at the kink position have little influence on the aerodynamic performances. However, the aerodynamic performances are getting worse when both the semispan length and the outer swept-forward angle are getting larger. The geometries optimized are greatly different from the wing planform of the base geometry, which is caused by shock stall. In comparison between the inner and outer wings, the aerodynamic performances of the outer wing are crucial to those of the entire wing.

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In this study, to acquire design guidelines for future aerodynamic wingtip design with a wing grid, the aerodynamic coefficients of a planar wing with a wing grid and a rectangular wing, employing CRM.65.airfoil, at low- and high-Mach number conditions are compared using numerical simulation. As the result, the planar wing with a wing grid generates the extra induced-drag coefficient when the lift coefficient is the same. This is because the wingtip vortices of the wing grid occur, and the pressure coefficient on the first wingtip becomes especially smaller. Therefore, there is no advantage in these conditions with a wing grid when no proper dihedral angle or twist angle is set.

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Behavior of Ryukyu trench, especially about mega-earthquake, is unknown based on seismic observation since late 19thcentury. On the other hand, slight geological evidence of large earthquakes and tsunami is reported in Okinawa Island. The author attempts to reinforce those evidence through bibliographic survey. “Kyu-yo” is the national history archive of Ryukyu Kingdom. Convulsions of nature from middle 17thcentury to late 19thcentury are described in the document. It indicates that there was megaquake cluster in late 18thcentury. In 1768, Shuri Castle was damaged by earthquake and King Sho Boku evacuated from his palace. After shock, tsunami hit Kerama Islands and Asa village was lost. The well-known and cruel “Yaeyama tsunami disaster” occurred in 1771. In this earthquake, seismic intensity in Okinawa, Kerama and Kume islands was greater than that in Yaeyama Islands. In 1791, Yonabaru port suffered huge tsunami caused by silent earthquake. Naha port and Motobu port were also at the mercy of the tsunami. Judging from intensity and distribution of phenomena, the three earthquakes occurred along Ryukyu trench, and were either Magnitude 8 or more. The archive tells that Ryukyu trench is an earthquake nest similar to Nankai trough. After the slow-slip in 1791, however, seismic gap continues in the area around Okinawa Island. It means that Ryukyu arc is accumulating distortion for the next megaquake cluster.

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People who do not belong to National Institute of Technology, Okinawa College (for example, the students who want to enroll KOSEN) may have no accounts on Blackboard Learn (online education system) and Microsoft Teams. So when we teach online for them, we should use another way. On this report, there are 4 methods.

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