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On the interplay between intrinsic and extrinsic instabilities of spatially localized patterns

2018年6月7日(木) 15:00 - 16:30

西浦 廉政 (東北大学 材料科学高等研究所 (AIMR) 教授)

Spatially localized dissipative structures are observed in various fields, such as neural signaling, chemical reactions, discharge patterns, granular materials, vegetated landscapes, binary convection and block copolymer nanoparticles. These patterns are much simpler than single living cells, however they seem to inherit several characteristic “living state” features, such as generation of new patterns, self-replication, switching to new dynamics via collisions and adaptive morphological changes to environments. These behaviors stem from an interplay between the intrinsic instability of each localized pattern and the strength of external signals. To understand such an interplay, we explore the global geometric interrelation amongst all relevant solution branches of a corresponding system with approximate unfolding parameters. For instance, it has been uncovered that large deformation via strong collision is mapped into the network of unstable patterns in infinite dimensional space, and that an organizing center for 1D pulse generators is a double homoclinicity of butterfly type. Large deformation of patterns is unavoidable so that a global geometric structure formed by all relevant solution branches gives us much more insight rather than conventional PDE approaches. We illustrate the impact of this approach for the case of pulse generators. We also report on the recent exciting finding, namely the formation of exotic 3D nanoparticles of block copolymers caused by the interplay between internal repulsion and affinity to external solvent, which is consistent with experimental results.

会場: 仁科ホール

配信:計算科学研究棟 305-2会議室 / SUURI-COOL (Kyoto)

イベント公式言語: 英語

RIKEN iTHEMSのアウトリーチについての研究会 2018

2018年6月1日(金) - 4日(月)

「ジャーナリストと研究者の双方向的関係の構築」のため、「ジャーナリストが科学教育、研究の現場に出来るだけ長期間滞在する」という「ジャーナリスト・イン・レジデンス・プログラム」が2010年度に数理科学分野で始まり、2017年度まで毎年行われています。これは数学の研究を外部から見てもらい、将来的には社会と数学を近づけようという試みです。今回は、これまでの「ジャーナリスト・イン・レジデンス・プログラム」による交流の実績の上で、2016年11月に始動した理化学研究所の数理創造プログラムの研究と社会の関連付けを探るとともに、今後のジャーナリストと研究者の双方向的関係の構築のための議論を行います。 会場：東京大学玉原国際セミナーハウス 群馬県沼田市上発知町玉原高原 当日の電話 FAX 0278-23-9836 世話人: 坪井 俊 理化学研究所 数理創造プログラム 副プログラムディレクター

会場: 東京大学玉原国際セミナーハウス

イベント公式言語: 日本語

Nerd Nite Tokyo

2018年5月11日(金) 20:00 - 22:00

カトゥリン・ボシゥメン (理化学研究所 数理創造プログラム (iTHEMS) 客員主管研究員 / Professor, Department of Physics, Ryerson University, Canada)

Nerd Nite is "the Discovery Channel with beer", a worldwide monthly event series that mixes presentations, performances, trivia, demos, music, and of course drinking. Nerd Nite Tokyo events are held in English. This time, Dr. Catherine Beauchemin (iTHEMS senior visiting scientist) will give a 20min. talk on the problems of being a physicist in the world of virology. Fee: 1000 JPY per person

会場: Nagatacho GRID（〒102-0093 東京都千代田区平河町2-5-3）

イベント公式言語: 英語

基本解近似解法による点渦力学系の数値解析

2018年4月17日(火) 16:00 - 17:30

榊原 航也 (京都大学 大学院理学研究科 特定助教)

iTHEMS / KUAMSジョイントセミナー

会場: 京都大学 北部総合教育研究棟 1階 益川ホール

イベント公式言語: 日本語

iTHEMS Mini-workshop/ Theoretical Biology Mini-workshop

2017年10月19日(木) 14:00 - 17:00

“Kazusa DNA Research Institute: Who is this?” Dr. Satoshi Tabata (Kazusa DNA Res Inst, Director) “Did the journey to strawberry start from Japan?” Dr. Sachiko Isobe (Kazusa DNA Res Inst, Lab Head) Strawberry (Fragaria × ananassa) is cultivated and consumed across the world. It is an allo-polyploidy species (2n = 8X = 56) with an estimated genome size of 1C = 708–720 Mb. Strawberry was artificially generated in the 16th century Europe, by crossing between two octoploid species, F. chiloensis and F. virginiana. The evolutionary origin and genome structure have been discussed and not fully determined. The first proposed structure was AABBBBCC model (Federova, 1946), then, Senanayake and Bringhurst (1967) proposed AAA’A’BBBB model. The fully allopolyploidy structure (AAA’A’BBB’B’) was suggested by Bringhurst in 1990 based on isozyme segregation. This model was also supported by the segregation patterns of CAPS markers (Kunihisa et al. 2011) and SSR markers (Isobe et al. 2013). However, just recently, Tennessen et al. (2014) proposed the AvAvBiBiB1B1B2B2, model, according to the results of targeted DNA capture and sequencing by using next generation sequencing (NGS) technology. In this model, Av represents the most F. vesca like genome, while Bi represents the most F, iinmae like genome. The origin of F. vesca is considered as North America, and F. iinumae is an endemic species in Japan. Our resent results of denovo whole genome sequencing support the AvAvBiBiB1B1B2B2 model, that suggest considerable part of the strawberry genome showed the highest similarity with F. iinumae.

イベント公式言語: 英語

組ひもと位相的混合

2017年6月26日(月) 14:00 - 15:00

金 英子 (大阪大学)

In mathematics, the braids are important tools for the knot theory, hyperbolic geometry, and dynamical systems etc. In the last ten years, the braids have been used to study mixing in fluids. Various simple mixing devices (e.g. taffy machines) have been developed. These devices utilize a particular type of braid, so-called a pseudo-Anosov type. The notion of pseudo-Anosov braids comes from the Nielsen-Thurston theory on the surface automorphisms, and the theory says that the devices using pseudo-Anosov braids are "efficient" in some sense. In this lecture, I will give a quick introduction of the Nielsen-Thurston theory and the classification of braids. I will give a picture of the "complexity" forced by pseudo-Anosov braids. In particular, I will explain why pseudo-Anosov braids are useful and why they can be used to build interesting mixing devices. Cosponsored by RIKEN iTHEMS and AIP Mathematical Science Team

会場: 理化学研究所 東京連絡事務所

イベント公式言語: 英語

Homological algebra, Renormalization and Transversality

2017年6月26日(月) 10:30 - 11:30

深谷 賢治 (Permanent Member, Simons Center for Geometry and Physics, Stony Brook University, New York, USA)

Transversality is a basic concept of differential topology and theory of manifold. Homological algebra may be regarded as a method to approximate `spaces' by an algebra and is a basic concept in agebraic topology. I would like to explain in this talk how they are related to some basic problem of quantum field theory such as renormalization. Cosponsored by RIKEN iTHEMS and AIP Mathematical Science Team

会場: 理化学研究所 東京連絡事務所

イベント公式言語: 英語

深層学習と物理

2017年6月5日(月) 13:00 - 18:00

We are happy to announce our 3rd joint symposium of Osaka CTSR, RIKEN iTHES/iTHEMS and Kavli IPMU, focusing this time on the topic of deep learning and its relation to fundamental physics. The rapid and vast applications of deep learning and artificial intelligence can potentially provide a breakthrough in various situations in fundamental physics. Invited speakers will deliver a cutting-edge progress in this interesting and developing fields, and participants are expected to join discussions. In addition, in the morning (9:00-12:00) at Nambu hall, we have an informal lecture course on deep learning by M. Taki (in Japanese). Osaka CTSR - RIKEN iTHES/iTHEMS - Kavli IPMU Joint Symposium

イベント公式言語: 英語