Volume 182

iTHEMS Weekly News Letter

Event Schedule

Events for the 5th week of January 2022

2022-01-20

Thursday, January 27, 10:00– 11:00 iTHEMS Biology Seminar
Friday, January 28, 12:30- Coffee Meeting
Saturday, January 29, 15:30- 16:40 RIKEN AIP-Suri-joshi Joint Seminar

Hot Topic

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Reading the World through the Window of Math Focusing on the Sensitivity of Young Researchers

2022-01-17

A column article about "Reading the World through the Window of Math" appeared on Imagineer Co., Ltd. Ten Minutes TV.
The article is based on the co-authored book "Reading the World through the Window of Math: Exploring Prime Numbers, AI, Biology, and the Universe" (edited by Tetsuo Hatsuda and Ryosuke Shibato, Iwanami Shoten), which was written by young researchers from iTHEMS.
Please see the related link for details.

Research News

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RIKEN NEWS: Uncovering the laws of evolution hidden in genomic information

2022-01-14

Jeffrey Fawcett (Senior Research Scientist) is interviewed on the RIKEN website.

Life on Earth has been around for about 4 billion years. Over the years, organisms have evolved into a wide variety of species. This is also the history of how the genomes have evolved. Jeffrey Fawcett (Senior Research Scientist, iTHEMS) is trying to unravel the mystery of how the differences between species arose by taking a mathematical science approach.

To read more, please see the related link.

Seminar Report

iTHEMS Biology Seminar by Dr. Wataru Nishima on January 13, 2022

2022-01-17

Dr. Wataru Nishima (New Mexico Consortium, USA) gave a very interesting presentation about his published paper on the spike protein of the SARS-CoV-2, the virus which causes COVID-19 [1]. He described the conformational change which the SARS-CoV-2 spike protein undergoes when it fuses with the host cell to initiate infection. His work offers and interesting alternative view of the process wherein parts of the spike protein ends up inside the host cell. This differs from the usual view where the spike protein would be left on the outside of the cell after virus fusion with the host. This alternative hypothesis could have important implication for better understanding disease severity, e.g. based on the possible toxic effect of spike protein components shed as part of the fusion process. Dr. Nishima's expertise is primarily in Molecular Dynamics and Bioinformatics and he is very interested to establish new collaborations with iTHEMS members.

Reported by Catherine Beauchemin

Reference

  1. Wataru Nishima and Marta Kulik, Full-Length Computational Model of the SARS-CoV-2 Spike Protein and Its Implications for a Viral Membrane Fusion Mechanism, Viruses 2021, 13(6), 1126 (2021), doi: 10.3390/v13061126

Seminar Report

DMWG Seminar by Dr. Kanji Mori on January 17, 2022

2022-01-18

In this era of multi-messenger astronomy, axion-like particle (ALP) searches using astrophysical transients are now excitingly discussed. ALPs are an extended class of particles from QCD axion, which could solve the strong CP problem of the Standard Model, and dark matter (DM) candidates of various connections to the physics beyond the Standard Model. ALPs could interact with our sector through their coupling to the photon, electron, and/or nucleons.

The coupling of ALP to the photon is previously investigated using observations of SN 1987A, the most famous supernova explosion. MeV gamma-ray signals are expected when considering the conversion of ALP outside the stellar envelope, hence no observations of the associated gamma-ray emission to the supernova lead to the constraint on the coupling strength, for example.

Also, the existence of such coupling should modify the dynamics of supernovae. When a star explodes, the difference between the masses of the progenitor star and the resulting compact object sources the radiation, neutrino emission, and kinetic energy of the ejecta material. ALP could be an additional channel for the energy release while its absorption heats the supernova. The balance between heating and cooling controls the supernova dynamics and shock restoration, which directly relates to the electromagnetic observables. Dr. Mori has shown that the heating rate is very sensitive to the coupling strength and enhancement of the electromagnetic emission is expected in the pre-supernova stage. The signatures could also be visible in the neutrino sector after the explosion.

The results are fantastic, and there are a lot of things to do. For example, the inclusion of the ALP-nucleon coupling effects is an interesting direction to pursue. Updates in the understanding of stellar models are important as well. We should see the signature of ALP in the near future in this field!

Reported by Nagisa Hiroshima

Seminar Report

iTHEMS Biology Seminar by Dr. Hiroyasu Miyazaki on January 20, 2022

2022-01-20

In the iTHEMS Biology Seminar on 20th January, Dr. Hiroyasu Miyazaki (RIKEN iTHEMS) gave a talk on the topological aspect of chemical reaction network. His talk is composed of two parts: motivation and result part and method part. In the first part, he mentioned the reduction of the chemical reaction network in E. Coli and its result which shows the same steady state as that before the reduction. In the second part, he explained how the network should be reduced. The topological information of the network can be described by using the matrix and the vector. He explained that the quotient network is defined to have a sequence of linear maps called “exact sequence”, which describes the relation among the original network, the subnetwork and the quotient network. We enjoyed his beautiful talk. From the audiences, the lively discussion arose during and after the talk. Thank you very much, Hiroyasu!

Reported by Hiroshi Yokota

Upcoming Events

Seminar

iTHEMS Biology Seminar

On Flow and Form at Low Reynolds Number

January 27 (Thu) at 10:00 - 11:00, 2022

Kenta Ishimoto (Associate Professor, Research Institute for Mathematical Sciences (RIMS), Kyoto University)

Cell locomotion is mechanically restricted by surrounding viscous fluids. With a focus on swimming cells in a low-Reynolds-number flow, I will give a brief introduction to microbiological fluid dynamics and present a 'hydrodynamic shape' theory at the cellular scale.

Venue: via Zoom

Event Official Language: English

External Event

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Ade Irma Suriajaya thumbnail
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RIKEN AIP-Suri-joshi Joint Seminar

January 29 (Sat) at 15:00 - 16:40, 2022

Ryosuke Iritani (Research Scientist, iTHEMS)
Ade Irma Suriajaya (Assistant Professor, Faculty of Mathematics, Kyushu University)
Motoko Kato (Assistant Professor, Faculty of Science, Ehime University)

"What are the personalities of AI and mathematical researchers? What kind of work do researchers do?" The RIKEN Center for Integrative Research on Innovative Intelligence (RIKEN AIP) and "Suri-joshi" are planning a joint event that will give high-school girls who are interested in mathematical scientists an opportunity to learn more about the fascinating work of AI and mathematical researchers.

Venue: via Zoom

Event Official Language: Japanese

Workshop

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Co-hosted by iTHEMS

Towards the Use of Data Assimilation for COVID-19 Investigations

February 14 (Mon) at 13:00 - 17:30, 2022

Catherine Beauchemin (Deputy Program Director, iTHEMS)
Takemasa Miyoshi (Team Leader, Data Assimilation Research Team, RIKEN Center for Computational Science (R-CCS))

This workshop aims to present recent investigations related to mathematical modeling of COVID-19 spread and impacts, and to foster the use of data assimilation techniques in future studies. It also aims to facilitate interactions and discussions among researchers from different fields such as epidemiology, economics, and mathematics. This workshop is jointly hosted by RIKEN Data Assimilation Research Team and by Nagoya University Graduate School of Mathematics, and supported by FY2021 RIKEN President's Discretionary Funds for COVID-19. A hybrid meeting is planned, but depending on the situation, an online version will be organized. Young researchers and students are encouraged to attend.

Program:
13:00 - 13:10 Opening
13:10 - 14:00 Hiroshi Nishiura (Kyoto University)
(35 min + 15 min Q&A) TBD

14:00 - 14:50 Catherine Beauchemin (RIKEN iTHEMS)
(35 min + 15 min Q&A) The straight line: simple and effective

14:50 - 15:10 Break

15:10 - 16:00 Taisuke Nakata (The University of Tokyo)
(35 min + 15 min Q&A) Balancing NPIs and Economic Activities

16:00 - 16:50 Qiwen Sun (RIKEN Data Assimilation Research Team, Nagoya University)
(35 min + 15 min Q&A) Analysis of COVID-19 in Japan with Extended SEIR model and ensemble Kalman filter

16:50 - 17:30 Discussion

Venue: Hybrid Format (RIKEN R-CCS room 107 and Zoom)

Event Official Language: English

External Event

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RIKEN Day: Let's Talk with Researchers! "Listening to the Ringing of a Black Hole"

February 25 (Fri) at 18:00 - 18:30, 2022

Naritaka Oshita (Special Postdoctoral Researcher, iTHEMS)

In the February RIKEN Day, we will have a talk with Naritaka Oshita, a researcher who is researching on the theme of "Listening to the Ringing of a Black Hole."

See related links for details.

Venue: via Zoom

Event Official Language: Japanese

Paper of the Week

Week 4, January 2022

2022-01-20

Title: Current-induced inverse symmetry breaking and asymmetric critical phenomena at current-driven tricritical point
Author: Masataka Matsumoto, Shin Nakamura
arXiv: http://arxiv.org/abs/2201.06894v1

Title: Global study of the scalar quasi-normal modes of Kerr-AdS${}_5$ black holes: Stability, thermality, and horizon area quantization
Author: Issei Koga, Naritaka Oshita, Kazushige Ueda
arXiv: http://arxiv.org/abs/2201.07267v1

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