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An economic premium principle in a multiperiod economy

Hideki Iwaki, Masaaki Kijima, Yuji Morimoto
2001 Insurance, Mathematics & Economics  
'One of examples of such products is ART (Alternative Risk 'Ikansfer) products (see Iwaki, Kijima and h4orimoto [9] for more details.).  ...  This paper considers a continuous-time economic equilibrium model for deriving the economic premium principle of Buhlmann [2, 31 and Iwaki, Kijima and Morimoto [9].  ...  Masaaki Kijima for helpful discussions and careful reading of this manuscript. The remaining errors are of course mine:  ... 
doi:10.1016/s0167-6687(00)00081-0 fatcat:bmqhbuh3rffufnc6z7tpgr44ya

Joint Action Syntax in Japanese Martial Arts

Yuji Yamamoto, Keiko Yokoyama, Motoki Okumura, Akifumi Kijima, Koji Kadota, Kazutoshi Gohara, Attila Szolnoki
2013 PLoS ONE  
Participation in interpersonal competitions, such as fencing or Japanese martial arts, requires players to make instantaneous decisions and execute appropriate motor behaviors in response to various situations. Such actions can be understood as complex phenomena emerging from simple principles. We examined the intentional switching dynamics associated with continuous movement during interpersonal competition in terms of their emergence from a simple syntax. Linear functions on return maps
more » ... fied two attractors as well as the transitions between them. The effects of skill differences were evident in the second-and third-order state-transition diagrams for these two attractors. Our results suggest that abrupt switching between attractors is related to the diverse continuous movements resulting from quick responses to sudden changes in the environment. This abrupt-switching-quick-response behavior is characterized by a joint action syntax. The resulting hybrid dynamical system is composed of a higher module with discrete dynamics and a lower module with continuous dynamics. Our results suggest that intelligent human behavior and robust autonomy in real-life scenarios are based on this hybrid dynamical system, which connects interpersonal coordination and competition.
doi:10.1371/journal.pone.0072436 pmid:24023740 pmcid:PMC3762806 fatcat:fqk2pjybbjddlms7o5ye7ceo5i

A Switching Hybrid Dynamical System: Toward Understanding Complex Interpersonal Behavior

Yuji Yamamoto, Akifumi Kijima, Motoki Okumura, Keiko Yokoyama, Kazutoshi Gohara
2018 Applied Sciences  
Complex human behavior, including interlimb and interpersonal coordination, has been studied from a dynamical system perspective. We review the applications of a dynamical system approach to a sporting activity, which includes continuous, discrete, and switching dynamics. Continuous dynamics identified switching between in- and anti-phase synchronization, controlled by an interpersonal distance of 0.1 m during expert kendo matches, using a relative phase analysis. In the discrete dynamical
more » ... m, return map analysis was applied to the time series of movements during kendo matches. Offensive and defensive maneuvers were classified as six coordination patterns, that is, attractors and repellers. Furthermore, these attractors and repellers exhibited two discrete states. Then, state transition probabilities were calculated based on the two states, which clarified the coordination patterns and switching behavior. We introduced switching dynamics with temporal inputs to clarify the simple rules underlying the complex behavior corresponding to switching inputs in a striking action as a non-autonomous system. As a result, we determined that the time evolution of the striking action was characterized as fractal-like movement patterns generated by a simple Cantor set rule with rotation. Finally, we propose a switching hybrid dynamics to understand both court-net sports, as strongly coupled interpersonal competition, and weakly coupled sports, such as martial arts.
doi:10.3390/app9010039 fatcat:cmc7gm7ow5hhrbcjdjpyjjhqui

Effects ofNrf2silencing on oxidative stress-associated intestinal carcinogenesis in mice

Yuh Yokoo, Aki Kijima, Yuji Ishii, Shinji Takasu, Takuma Tsuchiya, Takashi Umemura
2016 Cancer Medicine  
To assess the risk of colorectal cancer in humans with inactivation of NRF2, Nrf2-proficient (Nrf2 +/+ ) and -deficient (Nrf2 −/− ) mice were exposed to potassium bromate (KBrO 3 ) at concentrations of 750 or 1500 ppm for 52 weeks. Neoplastic proliferative lesions were observed in the small intestine and exhibited accumulations of βcatenin and cyclin D1. The lesions had characteristics similar to those in experimental models of human hereditary colorectal cancer. An additional 13-week study was
more » ... performed to examine the role of Nrf2 in the effects of oxidative stress. Significant increase in combined incidences of preneoplastic and neoplastic lesions in Nrf2 −/− mice administered high-dose KBrO 3 . In the short-term study, although 8-hydroxydeoxyguanosine (8-OHdG) levels in the epithelial DNA of Nrf2 −/− mice at the high dose were significantly lower than those of the corresponding Nrf2 +/+ mice, the difference was very small. mRNA levels of Nrf2-regulated genes were increased in Nrf2 +/+ mice. Overexpression of cyclooxygenase 2 (COX2) and increased numbers of proliferating cell nuclear antigen (PCNA)-positive cells in the jejunal crypts were observed in Nrf2 −/− mice administered high-dose KBrO 3 . Overall, these data suggested that individuals having single-nucleotide polymorphisms in NRF2 may have a risk of colorectal cancer to some extent. Cancer Medicine Open Access 1229
doi:10.1002/cam4.672 pmid:26899729 pmcid:PMC4924381 fatcat:bhirywtarvfevkipmdw6xbkzye

Effects of Agent-Environment Symmetry on the Coordination Dynamics of Triadic Jumping

Akifumi Kijima, Hiroyuki Shima, Motoki Okumura, Yuji Yamamoto, Michael J. Richardson
2017 Frontiers in Psychology  
., 2007b; anti-phase in one-on-one competing action: Kijima et al., 2012; Okumura et al., 2012) , with such states being more stable in the absence of further symmetry breaking factors.  ... 
doi:10.3389/fpsyg.2017.00003 pmid:28210231 pmcid:PMC5288381 fatcat:pq3fhy7cn5hcbo42jmwv6ibjum

Pleiotropic Effects of Exosomes as a Therapy for Stroke Recovery

Yuji Ueno, Kenichiro Hira, Nobukazu Miyamoto, Chikage Kijima, Toshiki Inaba, Nobutaka Hattori
2020 International Journal of Molecular Sciences  
Stroke is the leading cause of disability, and stroke survivors suffer from long-term sequelae even after receiving recombinant tissue plasminogen activator therapy and endovascular intracranial thrombectomy. Increasing evidence suggests that exosomes, nano-sized extracellular membrane vesicles, enhance neurogenesis, angiogenesis, and axonal outgrowth, all the while suppressing inflammatory reactions, thereby enhancing functional recovery after stroke. A systematic literature review to study
more » ... association of stroke recovery with exosome therapy was carried out, analyzing species, stroke model, source of exosomes, behavioral analyses, and outcome data, as well as molecular mechanisms. Thirteen studies were included in the present systematic review. In the majority of studies, exosomes derived from mesenchymal stromal cells or stem cells were administered intravenously within 24 h after transient middle cerebral artery occlusion, showing a significant improvement of neurological severity and motor functions. Specific microRNAs and molecules were identified by mechanistic investigations, and their amplification was shown to further enhance therapeutic effects, including neurogenesis, angiogenesis, axonal outgrowth, and synaptogenesis. Overall, this review addresses the current advances in exosome therapy for stroke recovery in preclinical studies, which can hopefully be preparatory steps for the future development of clinical trials involving stroke survivors to improve functional outcomes.
doi:10.3390/ijms21186894 pmid:32962207 pmcid:PMC7555640 fatcat:sdxlliy3ybc55hocmaj5pgiihi

A Critical Interpersonal Distance Switches between Two Coordination Modes in Kendo Matches

Motoki Okumura, Akifumi Kijima, Koji Kadota, Keiko Yokoyama, Hiroo Suzuki, Yuji Yamamoto, Ramesh Balasubramaniam
2012 PLoS ONE  
In many competitive sports, players need to quickly and continuously execute movements that co-adapt to various movements executed by their opponents and physical objects. In a martial art such as kendo, players must be able to skillfully change interpersonal distance in order to win. However, very little information about the task and expertise properties of the maneuvers affecting interpersonal distance is available. This study investigated behavioral dynamics underlying opponent tasks by
more » ... yzing changes in interpersonal distance made by expert players in kendo matches. Analysis of preferred interpersonal distances indicated that players tended to step toward and away from their opponents based on two distances. The most preferred distance enabled the players to execute both striking and defensive movements immediately. The relative phase analysis of the velocities at which players executed steps toward and away revealed that players developed anti-phase synchronizations at near distances to maintain safe distances from their opponents. Alternatively, players shifted to in-phase synchronization to approach their opponents from far distances. This abrupt phase-transition phenomenon constitutes a characteristic bifurcation dynamics that regularly and instantaneously occurs between in-and anti-phase synchronizations at a critical interpersonal distance. These dynamics are profoundly affected by the task constraints of kendo and the physical constraints of the players. Thus, the current study identifies the clear behavioral dynamics that emerge in a sport setting.
doi:10.1371/journal.pone.0051877 pmid:23284799 pmcid:PMC3527480 fatcat:7lbdqbkk6fcqxhvkyrterka2qy

Tako-tsubo Cardiomyopathy after Upper Gastrointestinal Tract Examination

Satoshi Kurisu, Ichiro Inoue, Takuji Kawagoe, Masaharu Ishihara, Yuji Shimatani, Takaki Hata, Yasuharu Nakama, Yasufumi Kijima, Eisuke Kagawa
2006 Internal medicine (Tokyo. 1992)  
F i g u r e 1 . T we l v e -l e a d e l e c t r o c a r d i o g r a m o n e h o u r a f t e r d o u b l e -c o n t r a s t u p p e r g a s t r o i n t e s t i n a l t r a c t e x a mi n a t i o n s h o we d S T -s e g me n t e l e v a t i o n i n l e a d s I I , I I I , a VF a n d V2 -6 . A 77-year-old male with appetite loss underwent double-contrast upper gastrointestinal tract examination. Although the study showed no gastrointestinal disease, the patient had chest oppressive sensation one
more » ... ur later. Twelve-lead electrocardiogram showed ST-segment elevation in leads II, III, aVF and V2-6 ( Fig. 1) . Emergency coronary angiography showed only a moderate atherosclerotic luminal narrowing in the mid right coronary artery. However, left ventriculography showed akinesia of the mid-to-distal portion of the left ventricular chamber, with hyperkinesia of the basal portion (Fig. 2) . Swallowed barium was also seen in the gastrointestinal tract. ST-segment elevation was resolved, and T wave became inverted 24 hours
doi:10.2169/internalmedicine.45.1803 pmid:16778347 fatcat:ivvervi5lfh4nkacvht7yeprea

Persistent Left Ventricular Dysfunction in Takotsubo Cardiomyopathy After Pacemaker Implantation

Satoshi Kurisu, Ichiro Inoue, Takuji Kawagoe, Masaharu Ishihara, Yuji Shimatani, Takaki Hata, Yasuharu Nakama, Yasufumi Kijima, Eisuke Kagawa
2006 Circulation Journal  
novel cardiac syndrome comprising transient left ventricular dysfunction with chest symptoms, electrocardiographic (ECG) changes and minimal myocardial enzymatic release has been gradually recognized worldwide 1-5 and is known as takotsubo cardiomyopathy in Japan because the end-systolic left ventriculogram resembles a "takotsubo", which is a pot used for trapping octopuses. Patients with takotsubo cardiomyopathy have a favorable prognosis in general, because the left ventricular dysfunction is
more » ... usually transient. We report 2 cases of takotsubo cardiomyopathy associated with pacemaker implantation that presented as persistent left ventricular dysfunction even during the convalescent stage. Case Reports Case 1 An 89-year-old woman with hypertension and left hemiparesis was admitted to hospital with dizziness. She was conscious, her blood pressure was 130/70 mmHg, and pulse rate was 38 beats/min. Her hematological test results were normal, and chest X-ray showed no pulmonary edema or cardiac enlargement. A 12-lead ECG showed sinus rhythm and complete atrioventricular block at a rate of 38 beats/min (Fig 1) , and echocardiography showed normal left ventricular function (ejection fraction =62%). Next day, she received a dualchamber pacemaker under local anesthesia. The pulse generator was located in the left pectoral region, and the 52-cm and 58-cm bipolar leads were positioned in the low right atrial septum and mid right ventricular septum, respectively. No complications occurred during the operation. She had chest discomfort 10 min after the operation, and her ECG showed significant ST-segment elevation in leads I, aVL and V2-6. Emergency coronary angiography showed Two cases of takotsubo cardiomyopathy occurred after pacemaker implantation, both in elderly women who received a dual-chamber pacemaker for complete atrioventricular block. They had persistent left ventricular dysfunction even during their convalescence. (Circ J 2006; 70: 641 -644) A 642 KURISU S et al.
doi:10.1253/circj.70.641 pmid:16636505 fatcat:5v7gaokvjvfrbm7mhim3wfk2ry

Oxidative Cracking of n-Butane over BiOCl Catalyst

Norihito Kijima, Koichi Matano, Masao Saito, Tomo Oikawa, Tomohiro Konishi, Hiroyuki Yasuda, Toshio Sato, Yuji Yoshimura
2000 Journal of the Japan Petroleum Institute  
doi:10.1627/jpi1958.43.89 fatcat:nkrggo6ghrhihml5dyhbqey7fa

Effectiveness of circular external fixator in periprosthetic fractures around the knee

Koji Nozaka, Naohisa Miyakoshi, Michio Hongo, Yuji Kasukawa, Hidetomo Saito, Hiroaki Kijima, Hiroyuki Tsuchie, Motoki Mita, Yoichi Shimada
2020 BMC Musculoskeletal Disorders  
The incidence of periprosthetic fractures after total joint arthroplasty (TJA) is rising due to an increasing number of TJAs performed annually and the growing elderly population. In many elderly patients with periprosthetic fractures, the bone strength is lowered due to the deterioration of bone quality and a decrease in bone quantity; rigid fixation of the fracture is difficult. It is a challenging operation for orthopedic surgeons. The usefulness of circular external fixation for
more » ... ic fractures has been reported in several case studies. The aim of this study was to investigate the rate of union and complications associated with circular external fixation in periprosthetic fractures around the knee. We included 19 patients with periprosthetic femur and tibial fractures who underwent osteosynthesis using a circular external fixator and had at least 2 years of follow-up. All patients had comorbidities and high risks associated with anesthesia. Tourniquets were not used in any of the patients. There were no cases in which the skin incision was placed, and the closed reduction technique was used in all cases. A 100% union rate was achieved with no serious complications. All fractures healed after a mean time of 14.3 ± 5.2 weeks (range, 8-38 weeks). The walking ability was the same level as before the injury in 13 cases. There are many comorbidities associated with periprosthetic fractures in elderly patients. Double-plate or revision surgery were largely invasive and had high risks associated with anesthesia. Circular external fixation is a feasible and effective treatment option because it provides stable fixation, prompt postoperative mobilization, and has no major complications, especially in elderly patients who are treated for periprosthetic fractures. Circular external fixation is a safe and reliable method for periprosthetic fractures around the knee in elderly patients. Level IV, retrospective case series.
doi:10.1186/s12891-020-03352-9 pmid:32438922 fatcat:kwryr45dzvhjtbj63bdbrox7hi

Switching Dynamics in an Interpersonal Competition Brings about "Deadlock" Synchronization of Players

Akifumi Kijima, Koji Kadota, Keiko Yokoyama, Motoki Okumura, Hiroo Suzuki, R. C. Schmidt, Yuji Yamamoto, Attila Szolnoki
2012 PLoS ONE  
In competitive sport game behavior, certain interpersonal patterns of movement coordination evolve even though each individual player only intends to exert their own strategy to win. To investigate this interpersonal pattern formation process, we asked pairs of naïve participants to engage in a play-tag game in which they had to remove a tag fastened to their partner's hip. Relative phase analysis of the players' step towards-away velocities indicated that anti-phase synchronization evolved
more » ... ss 10 repetitions of the game. We clarified evolution of this synchronization process using a dynamical model with an attractor (at relative p phase) and a repeller (at 0 relative phase) and discuss the self-organized nature of model and its ability to embody general solution for martial art interpersonal coordination.
doi:10.1371/journal.pone.0047911 pmid:23144834 pmcid:PMC3489899 fatcat:n7hkyt2bd5ff5oil4mezsbr2ne

Who Should Jump First? Three Peoples' Teamwork in a Symmetrical and Asymmetrical Game Space

Akifumi Kijima, Hiroyuki Shima, Motoki Okumura, Yuji Yamamoto, Michael J. Richardson
2018 Frontiers for Young Minds  
YUJI YAMAMOTO Professor of Research Center of Health, Physical Fitness, and Sports, Nagoya University, Japan and the secretary general of Japanese Society of Sport Psychology.  ...  Kijima, A., Shima, H., Okumura, M., Yamamoto, Y., and Richardson, M. J. 2017. Effects of agent-environment symmetry on the coordination dynamics of triadic jumping. Front.  ...  COPYRIGHT © 2018 Kijima, Shima, Okumura, Yamamoto and Richardson. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY).  ... 
doi:10.3389/frym.2018.00005 fatcat:svvjl6fb6raq3ohzu2e2fld4hy

Takotsubo-like Transient Biventricular Dysfunction with Pressure Gradients

Satoshi KURISU, Ichiro INOUE, Takuji KAWAGOE, Masaharu ISHIHARA, Yuji SHIMATANI, Naoya MITSUBA, Takaki HATA, Yasuharu NAKAMA, Tomohiko KISAKA, Yasufumi KIJIMA
2005 Internal medicine (Tokyo. 1992)  
A 78-year-old woman was admitted to our hospital due to chest oppressive sensation. Admission electrocardiography revealed ST-segment elevation in I, II, III, a VF and V2-6 leads. Left ventriculography showed apical akinesis and basal hyperkinesis with a pressure gradient of 60 mmHg between the left ventricular apex and the base. Right ventriculography also showed similar abnormal wall motion with a pressure gradient of 28 mmHg. Follow-up cardiac catheterization after 16 days showed normal wall
more » ... motion with no pressure gradients. However, dobutamine stress (10 g/kg/min) caused a pressure gradient of 60 mmHg between the left ventricular apex and the aorta. (Internal Medicine 44: 727-732, 2005)
doi:10.2169/internalmedicine.44.727 pmid:16093595 fatcat:n5lrn636r5gqxnsv5avhqv5q54

Combined effect of teriparatide and low-intensity pulsed ultrasound for nonunion: a case report

Koji Nozaka, Yoichi Shimada, Naohisa Miyakoshi, Shin Yamada, Michio Hongo, Yuji Kasukawa, Hidetomo Saito, Hiroaki Kijima
2014 BMC Research Notes  
Low-intensity pulsed ultrasound is a pain-free therapy performed daily at home by the patient and has been shown to promote fracture healing. Teriparatide is a parathyroid hormone preparation that activates osteoblastic bone formation and is also reported to be effective in promoting bony union. Case presentation: We report the case of a 56-year-old Japanese male with a femoral shaft fracture who underwent intramedullary osteosynthesis nailing initially. He had no radiologic or clinical sign of
more » ... healing 3 months later and low-intensity pulsed ultrasound was initiated at that time. He was reassessed in another 3 months, with evidence of mild bone consolidation but the fracture gap persisted. Subsequent treatment with human parathyroid hormone was initiated in combination with low-intensity pulsed ultrasound. Full fracture healing was present 6 months after beginning the combination low-intensity pulsed ultrasound and teriparatide. It is hypothesized that the potential additive effects of low-intensity pulsed ultrasound and teriparatide therapy ultimately triggered sufficient bone formation to support osseous union. Conclusion: The case reported herein is a femoral shaft atrophic nonunion in which traditional interventions failed. Successful fracture healing was finally achieved with low-intensity pulsed ultrasound and teriparatide therapy. This is the first reported case of diaphyseal nonunion with deterioration of bone quality in long bones resolved with teriparatide and low-intensity pulsed ultrasound.
doi:10.1186/1756-0500-7-317 pmid:24886079 pmcid:PMC4059730 fatcat:gsznejqhb5bc3dalhfxvhvuadq
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