Analysis of the phenomenon of speculative trading in one of its basic manifestations: postage stamp bubbles

We document and analyze the empirical facts concerning one of the clearest evidence of speculation in financial trading as observed in the postage collection stamp market. We unravel some of the mechanisms of speculative behavior which emphasize the role of fancy and collective behavior. In our conclusion, we propose a classification of speculative markets based on two parameters, namely the amplitude of the price peak and a second parameter that measures its ``sharpness''. This study is offered to anchor modeling efforts to realistic market constraints and observations.Comment: 9 pages, 5 figures and 2 tables, in press in Int. J. Mod. Phys.

Ultrafast single-channel machine vision based on neuro-inspired photonic computing

High-speed machine vision is increasing its importance in both scientific and technological applications. Neuro-inspired photonic computing is a promising approach to speed-up machine vision processing with ultralow latency. However, the processing rate is fundamentally limited by the low frame rate of image sensors, typically operating at tens of hertz. Here, we propose an image-sensor-free machine vision framework, which optically processes real-world visual information with only a single input channel, based on a random temporal encoding technique. This approach allows for compressive acquisitions of visual information with a single channel at gigahertz rates, outperforming conventional approaches, and enables its direct photonic processing using a photonic reservoir computer in a time domain. We experimentally demonstrate that the proposed approach is capable of high-speed image recognition and anomaly detection, and furthermore, it can be used for high-speed imaging. The proposed approach is multipurpose and can be extended for a wide range of applications, including tracking, controlling, and capturing sub-nanosecond phenomena.Comment: 30 pages, 12 figure

Pre- and Postoperative Ocular Events in Cataract Patients with Small Pupils who Underwent Cataract Surgery

Purpose：To analyze pre- and postoperative surgical events in cataract patients with small pupils who underwent cataract surgery.Patients and methods：We reviewed the medical records of patients who underwent cataract surgery between January 2009 and May 2014 at Dokkyo Medical University Koshigaya Hospital. Surgery was performed by four experienced surgeons. We included 106 eyes from 83 patients with pupil sizes ＜5 mm in diameter who required iris retractors during the cataract surgery （small pupil group）. The control group was comprised of 447 eyes from 319 patients with pupil sizes ＞5 mm in diameter who did not require a mechanical dilatation of the pupil during cataract surgery. Pre- and postoperative intra- or extraocular surgical events were analyzed.Results：Preoperative intra- or extraocular surgical events were observed in 36 eyes （34.0％） in the small pupil group and 72 eyes （16.1％） in the control group, with a significant difference observed for those who underwent laser iridotomy （P＜0.001） and trabeclectomy （P＜0.01）. Postoperative intra- or extraocular events were observed in 25 eyes （23.6％） in the small pupil group and 61 eyes （13.7％） in the control group, with significant differences observed for those who underwent the following procedures：trabeculectomy （P＜0.001）, sub-Tenon’s injection of triamcinolone acetonide （P＜0.001）, and posterior capsulotomy （P＝0.012）.Conclusion：Cataract patients with small pupils often have pre- and postoperative intra- or extraocular surgical events. It should be recognized that cataract surgery is only one step in the treatment of cataract patients with small pupils

LIPUS effect on lateral tooth movement

Introduction: Because mechanical stimulation of the periodontal ligament (PDL) by low-intensity pulsed ultrasound (LIPUS) has been shown to increase the speed of bone remodeling, the aim of this study was to examine the effects of LIPUS stimulation on the rate of tooth movement and bone remodeling during lateral tooth movement. Methods: Twelve-week-old Wistar rats were divided into two groups. The LIPUS group received experimental tooth movement with LIPUS stimulation, and the tooth movement (TM) group had experimental tooth movement without LIPUS. For the LIPUS and TM groups, the upper right first molars were moved labially with fixed appliances. LIPUS exposure was placed in the region corresponding to the right maxillary first molar. Three days after tooth movement, tartrate-resistant acid phosphatase (TRAP) was examined. Fourteen days after tooth movement, the intermolar width, bone mineral content (BMC), and bone volume fraction (BV/TV) were examined by micro computed tomography (micro-CT), and newly formed bone was measured histomorphometrically. Results: The number of TRAP-positive cells at the compressed region was obviously greater in the LIPUS group. The intermolar width was significantly greater in the LIPUS group than in the TM group. The alveolar bone around the maxillary first molar showed no differences in BMC or BV/TV between the LIPUS and TM groups. The LIPUS group exhibited a significantly greater amount of newly formed alveolar bone than the TM group. Conclusions: The present study provides evidence of the beneficial effects of LIPUS on the lateral tooth movement