Search

Your search keyword '"Okuma, S."' showing total 826 results
Start Over Author "Okuma, S."
826 results on '"Okuma, S."'

2. Perspective on Reversible to Irreversible Transitions in Periodic Driven Many Body Systems and Future Directions For Classical and Quantum Systems

Author

Reichhardt, C., Regev, Ido, Dahmen, K., Okuma, S., and Reichhardt, C. J. O.

Subjects
Condensed Matter - Statistical Mechanics, Condensed Matter - Materials Science, Condensed Matter - Soft Condensed Matter, Condensed Matter - Strongly Correlated Electrons
Abstract

Reversible to irreversible (R-IR) transitions arise in numerous periodically driven collectively interacting systems that, after a certain number of driving cycles, organize into a reversible state where the particle trajectories repeat, or remain irreversible with chaotic motion. R-IR transitions were first systematically studied for periodically sheared dilute colloids, and appear in a wide variety of both soft and hard matter systems, including amorphous solids, crystals, vortices in type-II superconductors, and magnetic textures. In some cases, the reversible transition is an absorbing phase transition with a critical divergence in the organization time scale. R-IR systems can store multiple memories and exhibit return point memory. We give an overview of R-IR transitions including recent advances in the field, and discuss how the general framework of R-IR transitions could be applied to a much broader class of periodically driven nonequilibrium systems, including soft and hard condensed matter systems, astrophysics, biological systems, and social systems. Some likely candidate systems are commensurate-incommensurate states, systems exhibiting hysteresis or avalanches, and nonequilibrium pattern forming states. Periodic driving could be applied to hard condensed matter systems to see if R-IR transitions occur in metal-insulator transitions, semiconductors, electron glasses, electron nematics, cold atom systems, or Bose-Einstein condensates. R-IR transitions could also be examined in dynamical systems where synchronization or phase locking occurs. We discuss the use of complex periodic driving such as changing drive directions or multiple frequencies as a method to retain complex multiple memories. Finally, we describe features of classical and quantum time crystals that could suggest the occurrence of R-IR transitions in these systems., Comment: 25 pages, 27 figures

Published
2022
Full Text
View/download PDF

9. Visual field defects and changes in macular retinal ganglion cell complex thickness in eyes with intrachoroidal cavitation are similar to those in early glaucoma

Author

Okuma S, Mizoue S, and Ohashi Y

Subjects
Intrachoroidal Cavitation, Visual Field, Ganglion Cell Complex, Glaucoma, Ophthalmology, RE1-994
Abstract

Shinichi Okuma,1 Shiro Mizoue,2,3 Yuichi Ohashi3 1Department of Ophthalmology, Sumitomo Besshi Hospital, Niihama-shi, 2Department of Ophthalmology, Minami-Matsuyama Hospital, Matsuyama-shi, 3Department of Ophthalmology, Ehime University School of Medicine, Toon-shi, Ehime, Japan Background/aims: To examine the characteristics of visual field defects and optical coherence tomography (OCT) findings in eyes with intrachoroidal cavitation (ICC) and investigate the similarities between these results and glaucomatous changes.Methods: We retrospectively analyzed patients diagnosed with ICC based on peripapillary radial cross-sectional scans performed with OCT. Visual field was measured with the Humphrey automated visual field analyzer SITA standard central 24-2 program, and macular ganglion cell complex (GCC) thickness was measured in 9×9 mm areas on OCT. The positive rates for the Anderson criteria, site of visual field defect, and mean GCC thickness in each quadrant were compared; the association between these results and ICC location was assessed.Results: Fifteen eyes from eleven patients (five males and six females; mean age, 54.6±10.7 years) were selected for investigation. ICC was detected in the inferior temporal side of the optic disc in all studied eyes. The positive rate for the Anderson criteria was 73.3% (11/15 eyes). Visual field defects were most commonly observed in the cluster that corresponded to the superior Bjerrum area (53.3%; 8/15 eyes). GCC thickness was significantly lower in the inferior side, where the ICC was located, than the superior side, where the ICC was absent (P=0.0001). GCC thinning that correlated with ICC was observed in 66.7% (10/15 eyes) of the ICC eyes.Conclusion: Visual field and GCC findings on OCT in ICC eyes are extremely similar to those observed in superior visual field defect-type early glaucoma, indicating a possible difficulty in distinguishing the two conditions. Keywords: intrachoroidal cavitation, visual field, ganglion cell complex, glaucoma

Published
2016

Catalog

Books, media, physical & digital resources
See catalog results