堆積物重力流ベッドフォームの形成条件

京都大学新制・課程博士博士(理学)甲第23017号理博第4694号新制||理||1673(附属図書館)京都大学大学院理学研究科地球惑星科学専攻(主査)准教授 成瀬 元, 准教授 堤 昭人, 教授 生形 貴男学位規則第4条第1項該当Doctor of ScienceKyoto UniversityDGA

Charged scalars confronting neutrino mass and muon g-2 anomaly

The present work introduces two possible extensions of the Standard Model Higgs sector. In the first case, the Zee-Babu type model for the generation of neutrino mass is augmented with a scalar triplet and additional singly charged scalar singlets. The second scenario, on the other hand, generalizes the Type-II seesaw model by replicating the number of the scalar triplets. A $\mathbb{Z}_3$ symmetry is imposed in case of both the scenarios, but, allowed to be violated by terms of mass dimension two and three for generating neutrino masses and mixings. We examine how the models so introduced can explain the experimental observation on the muon anomalous magnetic moment. We estimate the two-loop contribution to neutrino mass induced by the scalar triplet, in addition to what comes from the doubly charged singlet in the usual Zee-Babu framework, in the first model. On the other hand, the neutrino mass arises in the usual Type-II fashion in the second model. In addition, the role of the $\mathbb{Z}_3$ symmetry in suppressing lepton flavor violation is also elucidated.Comment: 4 tables, 14 captioned figure

Arbitrary Univariate Function Evaluation and Re-Encryption Protocols over Lifted-ElGamal Type Ciphertexts

Homomorphic encryption (HE) is one of the main tools in secure multiparty computation (MPC), and the (elliptic-curve) lifted-ElGamal cryptosystem is certainly the most efficient among the existing HE schemes. However, the combination of MPC with this most efficient HE has rarely appeared in the literature. This is mainly because the major known techniques for (additively) HE-based MPC are not available for this scheme due to its typical restriction that only a plaintext in a small range can be efficiently decrypted. In this paper, we resolve this problem. By our technique, a Server having a lifted-ElGamal ciphertext $[[m]]$ with unknown small plaintext $m$ can obtain a ciphertext $[[ \varphi(m) ]]$ for an arbitrary function $\varphi$ by just one-round communication with a semi-honest Client (and also two-rounds with a malicious Client) having a decryption key, where $m$ is kept secret for both parties. This property enlarges much the variations of MPC based on the most efficient lifted-ElGamal cryptosystem. As an application, we implemented MPC for exact edit distance between two encrypted strings; our experiment for strings of length $1024$ shows that the protocol takes only $45$ seconds in LAN environments and about $3$ minutes even in WAN environments. Moreover, our technique is also available with other lifted-ElGamal type HE schemes and admits different keys/schemes for the original and the resulting ciphertexts. For example, we can securely convert a level-2 (i.e., after multiplication) ciphertext for some two-level HE schemes into a level-1 (i.e., before multiplication) ciphertext, and securely apply arbitrary functions $\varphi(m)$ to encrypted plaintexts for some attribute-based HE schemes. This is the first result (even by using communication) on realizing these two functionalities

Relating the Flow Processes and Bedforms of Steady-State and Waning Density Currents

© Copyright© 2020 de Cala, Ohata, Dorrell, Naruse, Patacci, Amy, Simmons, McLelland and McCaffrey. The interaction between turbidity currents and mobile substrates can lead to the development of different types of bedforms. Although much research has been conducted on bedform development beneath open channel flows, research into bedform development beneath waning gravity currents is relatively rare. Analysis of density current-related bedform development has therefore relied upon open channel flow phase diagrams. We report on an experimental study designed to assess the development of bedforms under steady and waning saline density currents. The experimental density currents developed stepped density profiles in which a higher-density basal zone was separated from the ambient fluid by a zone of intermediate density; any bedforms that developed were contained within the bottom layer of the current. Under different conditions ripples, dunes, downstream migrating antidunes and long wavelength antidunes were observed to form and could be distinguished based on their interactions and phase relationships with the upper surface of the lower denser layer of the current. Due to limited mixing between the upper and lower layer of the current and maintenance of current momentum, currents set with slowing discharge flow rates maintained a steady flow velocity in the lower layer of the flow. As a result, sustained bedform formative conditions were achieved within this lower layer, while waning current conditions effected the rest of the flow. Under waning currents, it was seen how pre-existing bed states can determine the subsequent evolution of bedforms. This illustrates the limitations of existing phase diagrams as they do not account for trajectory or rate of passage of flows through different bedform phase spaces. In order to establish a reliable quantitative association between the flow regime and the type of bedform development, it is critical to adopt an appropriate Froude number calculation method for stratified flow. The updated density current phase diagram indicates supercritical flow can be achieved at lower flow velocities than for open channel flows due to the effects of reduced gravity. Bedform depositional structures found in outcrop and on the modern sea floor provide data that helps to interpret the hydrodynamic and sedimentological character of the current that formed them. Therefore, understanding the processes involved in bedform development beneath density currents will enable more accurate estimation of the properties of flows

Relation between abnormal synergy and gait in patients after stroke

[Background]The abnormal synergy seen in patients after stroke is considered to limit the ability of these patients. However, in the lower extremity, antigravity torque generation rather than precise movement is needed for functions such as sit-to-stand movement and gait. Therefore, the ability to generate torque may be important either as a primary movement or as an abnormal synergy. We attempted to quantify the torque generation in the lower limb, selectively and as an abnormal synergy, and its relation with gait. [Methods]Selectively generated plantar flexion torque in the ankle and plantar flexion torque secondarily generated accompanying maximal hip extension (i.e., torque generated with abnormal synergy) were measured in subjects after stroke and control subjects. In subjects after stroke, secondary torque generation while controlling hip extension torque as 25%, 50%, and 75% of the maximal hip extension was also measured. The relation of torque generation with the gait speed and timed-up-and go test (TUG) was also analyzed. [Results]In subjects after stroke, there was no difference between the amount of plantar flexion torque generated secondarily and the selectively generated torque, whereas the selective torque was significantly greater in control subjects. Pearson product?moment correlation coefficient analysis revealed that TUG speed is related to secondarily generated torque accompanying maximal hip extension but not with selectively generated torque. [Conclusion] Secondarily generated torque was found to be a factor that affects TUG speed, and the ability to generate torque even through abnormal synergy may help for gait ability in subjects after stroke

Case report: A novel approach of closed-loop brain stimulation combined with robot gait training in post-stroke gait disturbance

Most post-stroke patients have long-lasting gait disturbances that reduce their daily activities. They often show impaired hip and knee joint flexion and ankle dorsiflexion of the lower limbs during the swing phase of gait, which is controlled by the corticospinal tract from the primary motor cortex (M1). Recently, we reported that gait-synchronized closed-loop brain stimulation targeting swing phase-related activity in the affected M1 can improve gait function in post-stroke patients. Subsequently, a gait-training robot (Orthobot®) was developed that could assist lower-limb joint movements during the swing phase of gait. Therefore, we investigated whether gait-synchronized closed-loop brain stimulation combined with robot-assisted training targeting the swing phase could enhance the recovery of post-stroke gait disturbance. A 57-year-old female patient with chronic post-stroke hemiparesis underwent closed-loop brain stimulation combined with robot-assisted training for 10 min 2 years after left pons infarction. For closed-loop brain stimulation, we used transcranial oscillatory electrical current stimulation over the lesioned M1 foot area with 1.5 mA of DC offset and 0–3 mA of sine-wave formed currents triggered by the paretic heel contact to set the maximum current just before the swing phase (intervention A; two times repeated, A1 and A2). According to the N-of-1 study design, we also performed sham stimulation (intervention B) and control stimulation not targeting the swing phase (intervention C) combined with robot-assisted training in the order of A1-B-A2-C interventions. As a result, we found larger improvements in gait speed, the Timed Up and Go test result, and muscle strength after the A1 and A2 interventions than after the B and C interventions. After confirming the short-term effects, we performed an additional long-term intervention twice a week for 5 weeks, for a total of 10 sessions. Gait parameters also largely improved after long-term intervention. Gait-synchronized closed-loop brain stimulation combined with robot-assisted training targeting the swing phase of gait may promote the recovery of gait function in post-stroke patients. Further studies with a larger number of patients are necessary

Arctic weather in 2012 summer and influences on Arctic Environment

第3回極域科学シンポジウム/特別セッション「これからの北極研究」11月28日（水） 国立極地研究所 2階大会議

脳性麻痺児に対する筋厚測定の臨床的有用性

京都大学0048新制・論文博士博士(医学)乙第12416号論医博第1995号新制||医||978(附属図書館)27512(主査)教授 福山 秀直, 教授 髙橋 良輔, 教授 中山 健夫学位規則第4条第2項該当Doctor of Medical ScienceKyoto UniversityDA