The University of the Ryukyus , abbreviated to Ryūdai , is a national university of Japan in Okinawa Prefecture. It is located in the Senbaru neighborhood of the town of Nishihara, with its campus bordering both the village of Nakagusuku and the city of Ginowan. It is the westernmost national university of Japan and the largest public university in Okinawa Prefecture. Wikipedia.
Oda I.,University of Ryukyus
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2016
We study Weyl symmetry (local conformal symmetry) in unimodular gravity. It is shown that the Noether currents for both Weyl symmetry and global scale symmetry vanish exactly as in conformally invariant scalar-tensor gravity. We clearly explain why in the class of conformally invariant gravitational theories, the Noether currents vanish by starting with conformally invariant scalar-tensor gravity. Moreover, we comment on both classical and quantum-mechanical equivalences in Einstein's general relativity, conformally invariant scalar-tensor gravity, and the Weyl-transverse gravity. Finally, we discuss the Weyl current in the conformally invariant scalar action and see that it is also vanishing. © 2016 American Physical Society.
Oda I.,University of Ryukyus
Advanced Studies in Theoretical Physics | Year: 2016
We construct an induced gravity (pregeometry) where both the Newton constant and the cosmological constant appear as integration constants in solving field equations. By adding the kinetic terms of ghosts and antighosts, an action of the induced gravity is transformed to a topological field theory. Moreover, by solving field equations of the topological field theory in the FRW universe, we find an ination solution. The present study might shed some light on a close relationship between the induced gravity and the topological quantum field theory. © 2016 Antonio Zecca.
Oda I.,University of Ryukyus
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013
We consider a coupling of dilaton gravity to the classically scale-invariant B-L extended standard model, which has been recently proposed as a phenomenologically viable model realizing the Coleman-Weinberg mechanism of breakdown of the electroweak symmetry. It is shown in the present model that without recourse to the Coleman-Weinberg mechanism, the B-L gauge symmetry is broken in the process of spontaneous symmetry breakdown of scale invariance at the tree level, and as a result the B-L gauge field becomes massive via the Higgs mechanism. Since the dimensionful parameter is only the Planck mass in our model, one is forced to pick up very small coupling constants if one wishes to realize the breaking of the B-L symmetry at the TeV scale. © 2013 American Physical Society.
Dobata S.,University of Ryukyus
Proceedings. Biological sciences / The Royal Society | Year: 2012
Colonies of eusocial Hymenoptera, such as ants, bees and wasps, have long been recognized as candidates for the study of genomic imprinting on the grounds of evolutionary conflicts that arise from close interactions among colony members and relatedness asymmetry owing to haplodiploidy. Although a general kinship theory of genomic imprinting predicts its occurrence under various circumstances of the colony life cycle, new theoretical approaches are required to account for the specifics of real colonies based on recent advances in molecular-level understanding of ants and honeybees. Using a multivariate quantitative genetic model, we examined the potential impact of genomic imprinting on genes that determine the carrier female's propensity to develop into the queen caste. When queen overproduction owing to the increased propensity comes at a colony-level cost, the conflict between maternally and paternally inherited genes in polyandrous (queen multiple mating) colonies favours genomic imprinting. Moreover, we show that the genomic imprinting can occur even under monandry (queen single mating), once incorporating the costs differentially experienced by new males and new queens. Our model predicts the existence of imprinted 'genetic royal cheats' with patriline-specific expression in polyandrous colonies, and seems consistent with the paternal effect on queen determination in monandrous Argentine ants.
Oda I.,University of Ryukyus
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2013
We consider a coupling of conformal gravity to the classically scale-invariant B-L extended standard model which has been recently proposed as a phenomenologically viable model realizing the Coleman-Weinberg mechanism of breakdown of the electroweak symmetry. As in a globally scale-invariant dilaton gravity, it is also shown in a locally scale-invariant conformal gravity that without recourse to the Coleman-Weinberg mechanism, the B-L gauge symmetry is broken in the process of spontaneous symmetry breakdown of the local scale invariance (Weyl invariance) at the tree level and as a result the B-L gauge field becomes massive via the Higgs mechanism. As a bonus of conformal gravity, the massless dilaton field does not appear and the parameters in front of the non-minimal coupling of gravity are completely fixed in the present model. This observation clearly shows that the conformal gravity has a practical application even if the scalar field does not possess any dynamical degree of freedom owing to the local scale symmetry. © 2013 Elsevier B.V.
University of Ryukyus and Okinawa Research Center Co. | Date: 2015-08-19
The object of the invention is to provide a method of manufacturing a fraction containing nobiletin and tangeretin at high concentrations, which is excellent in terms of safety, economic efficiency, and the potential for industrialization. The object is achieved by a method of manufacturing a composition containing nobiletin and tangeretin, comprising (1-1) a step of treating citrus fruit with hot water to obtain a hot water-treated product; (1-2) a step of drying the hot water-treated product to obtain a dried product; (1-3) a step of treating the dried product with a solvent capable of dissolving nobiletin and tangeretin to obtain a nobiletin and tangeretin solution; (3) a step of concentrating and/or drying the nobiletin and tangeretin solution to obtain a nobiletin and tangeretin concentrate; and (4) a step of treating the nobiletin and tangeretin concentrate with a dilute alkali to obtain a composition containing nobiletin and tangeretin as an insoluble component, and by a composition containing nobiletin and tangeretin at high concentrations manufactured by the method.
University of Ryukyus and Osaka Gas Co. | Date: 2014-08-20
A solar light (heat) absorption material which has an excellent solar light (heat) absorbing ability and a simple structure, and may be used as a low-cost and high-performance heat absorption/accumulation material. Also, a solar light (heat) absorption/control building component including the solar light (heat) absorption material that allows for easy change of its solar light (heat) absorption/control ability. The material includes particles dispersed into a liquid medium having a specific heat ranging from 0.4 to 1.4 cal/g/ C. and a melting point of 5 C. or lower. The dispersed particles have L*value of 30 or less as determined by the CIE-Lab color system (light source D65).
University of Ryukyus | Date: 2015-12-16
Provided is a hand exoskeleton device that is compact, lightweight, is worn at the fingers of a human body, and is capable of assisting in activities of daily living. The hand exoskeleton device performs motion conversion by means of a single drive means by means of a three-layer sliding spring mechanism, thereby transmitting motive force with respect to the metacarpophalangeal joints, the proximal interphalangeal joints, and the distal interphalangeal joints of the fingers of a human, thus being able to assist in activities of daily living. By means of the hand exoskeleton device, it is possible to achieve a device that supports the grasping action of the fingers of a human body in a manner that is more lightweight and compact than has been conventional. The hand exoskeleton device is characterized by being able to transmit a large driving force and being able to drive the flexion and extension of the three joints of the fingers by means of a single drive means. Furthermore, the device main body has flexibility, and so driving is possible in a safe manner.
University of Ryukyus | Date: 2013-09-27
The invention provides a composition for prevention or treatment of a disease associated with the production of an autoantibody. Specifically, it provides a composition for the prevention or treatment of a disease associated with the production of an autoantibody, which comprise royal jelly as an active ingredient.
Watanabe H.,Japan National Institute of Agrobiological Science |
Tokuda G.,University of Ryukyus
Annual Review of Entomology | Year: 2010
Despite the presence of many carbohydrolytic activities in insects, their cellulolytic mechanisms are poorly understood. Whereas cellulase genes are absent from the genomes of Drosophila melanogaster or Bombyx mori, other insects such as termites produce their own cellulases. Recent studies using molecular biological techniques have brought new insights into the mechanisms by which the insects and their microbial symbionts digest cellulose in the small intestine. DNA sequences of cellulase and associated genes, as well as physiological and morphological information about the digestive systems of cellulase-producing insects, may allow the efficient use of cellulosic biomass as a sustainable energy source. © 2010 by Annual Reviews All rights reserved.