Volume 102
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Volume 102
May 8, 2020
Seminar Report
Second iTHEMS Biology Seminar on April 30, 2020
2020-05-07
On 30 April, Euki Yazaki, who joined iTHEMS in April, gave a talk at the second iTHEMS Biology Seminar. Euki's main research motivation is to understand the diversity and evolution of eukaryotes, especially by focusing on microorganisms called "protists". Most of you probably know nothing about protists. In fact, protist is not a proper phylogenetic group. It is "any eukaryotic organism that is not an animal, plant, or fungus" (from Wikipedia) - i.e. a category to dump all the eukaryotes that most people don't know about and don't care about. Yet, as Euki illustrated, they make up most of the phylogenetic diversity of eukaryotes, and there are still many many species that haven't been discovered. He described his previous research where he isolated an unknown protist from Palau which was different from any other protist that had been discovered, and determined its phylogenetic placement by large-scale DNA sequence data analyses. Euki and I believe that protists hold the key to understanding the origin of eukaryotes and to uncover some new exciting biology. Euki's talk also sparked interest from non-biologists to learn more about phylogenetics, a topic that involves lots of mathematics, which will hopefully be the topic of a seminar in the near future.
- Jeffrey Fawcett
Analyses of large-scale sequence data from “PROTIST” can reveal the eukaryotic phylogeny and evolution
April 30 (Thu) at 10:00 - 10:45, 2020
Upcoming Events
Colloquium
Emergence of life in an inflationary universe
May 11 (Mon) at 15:30 - 17:00, 2020
Tomonori Totani (Professor, Department of Astronomy, Graduate School of Science, The University of Tokyo)
The origin of life may be the greatest mystery in natural science. Especially, we know almost nothing about how the first biological molecule (possibly an RNA) appeared from abiotic chemical processes. A widespread notion is that the abiogenesis probability is extremely low when we consider only random chemical reactions to polymerize a large biological molecule. However, we do not know any more efficient polymerization process expected to work in a realistic prebiotic environment. Here, I consider this problem from a viewpoint of cosmology. Cosmologists agree that the universe created by an inflation should extend far beyond the observable universe (13.8 billion light year radius). Then the inflationary universe may be sufficiently large to produce many abiogenesis events, even if we consider only the basic random polymerization. I will give a quantitative answer to this question, and discuss various implications about the origin-of-life studies.
Venue: via Zoom
Event Official Language: English
Seminar
How many electrons can atoms bind?
May 13 (Wed) at 16:00 - 18:10, 2020
Yukimi Goto (Special Postdoctoral Researcher, iTHEMS)
In this talk, I will introduce the mathematical studies on the ionization problem. Some experimental & numerical evidences say that any doubly charged atomic ion X^{2-} is not stable. This 'fact' is called the ionization conjecture in mathematical physics literatures. My hope is to illustrates the interplay between mathematical and physical ideas. The talk is directed towards researchers on various aspects of quantum mechanics. In the first part, we will discuss the many-body aspects of quantum mechanics and introduce some basic notions. The second part will deal with the mathematical results in some approximation theories.
References
- T. Andersen, H. K. Haugen and H. Hotop, "Binding Energies in Atomic Negative Ions: III," J. Phys. Chem. Ref. Data 28 1511-1533 (1999).
- H. Hogreve, "On the maximal electronic charge bound by atomic nuclei," J. Phys. B 31 L439-446 (1998).
- A V. Sergeev, and S. Kais, "Critical nuclear charges for N-electron atoms," Int. J. Quant. Chem. 75 533-542 (1999).
Venue: via Zoom
Event Official Language: English
Paper of the Week
Week 1 & 2 of May
2020-05-07
Title: How the deprecation of Java applets affected online visualization frameworks -- a case study
Author: Martin Skrodzki
arXiv: http://arxiv.org/abs/2004.13254v2
Title: Universal Error Bound for Constrained Quantum Dynamics
Author: Zongping Gong, Nobuyuki Yoshioka, Naoyuki Shibata, Ryusuke Hamazaki
arXiv: http://arxiv.org/abs/2001.03419v4
Title: Error bounds for constrained dynamics in gapped quantum systems: Rigorous results and generalizations
Author: Zongping Gong, Nobuyuki Yoshioka, Naoyuki Shibata, Ryusuke Hamazaki
arXiv: http://arxiv.org/abs/2001.03421v4
Title: Liouvillian Skin Effect: Slowing Down of Relaxation Processes without Gap Closing
Author: Taiki Haga, Masaya Nakagawa, Ryusuke Hamazaki, Masahito Ueda
arXiv: http://arxiv.org/abs/2005.00824v1
Title: Variational Shape Approximation of Point Set Surfaces
Author: Martin Skrodzki, Eric Zimmermann, Konrad Polthier
arXiv: http://arxiv.org/abs/2005.01003v1
Title: Vector Fields and Paul Klee -- A Summer School Course for gifted High-School Students
Author: Martin Skrodzki, Henriette Lipschütz
arXiv: http://arxiv.org/abs/2005.01983v1
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