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

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.

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.

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

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

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

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