SIAM News Blog

DS23 Prize Spotlight

Congratulations to Victoria Booth, the 2023 J. D. Crawford Prize recipient, and Yoshiki Kuramoto, the 2023 Jürgen Moser Lecturer. Learn more about the prize recipients below.

Victoria Booth

Dr. Victoria Booth, University of Michigan, is the 2023 recipient of the J. D. Crawford Prize for her exceptional research in mathematical biology and in particular the formulation, analysis, and interpretation of dynamical systems models of sleep-wake cycles. Booth will be recognized at the 2023 SIAM Conference on Applications of Dynamical Systems (DS23) on Sunday, May 14 at 8:25 p.m. PT.

The SIAM Activity Group on Dynamical Systems (DS) awards the J. D. Crawford Prize every two years to one individual for recent outstanding work on a topic in nonlinear science, as evidenced by a publication in English in a peer-reviewed journal within the four calendar years preceding the award year.

The term “nonlinear science" is used in the spirit of the SIAM Activity Group on DS conferences. Specifically, it includes dynamical systems theory and its applications as well as experiments, computations, and simulations.

Dr. Booth earned a bachelor’s degree with highest honors in mathematics at Smith College and a Ph.D. in applied mathematics at Northwestern University. She then held a postdoctoral fellowship at the National Institutes of Health before joining the faculty of the department of mathematical sciences at the New Jersey Institute of Technology in 1996. Since 2004, she has held joint appointments in the departments of mathematics and anesthesiology at the University of Michigan as a mathematics professor and an associate professor, respectively. Her research is in computational and mathematical neuroscience with a particular focus on modeling neural mechanisms for regulation of sleep-wake states, circadian rhythms, and neuromodulation. Learn more about Dr. Booth

Q: Why are you excited to receive the award?

A: I’m thrilled and honored to have the work on modeling sleep-wake regulation and circadian rhythms that I’ve been doing with my wonderful friend and collaborator Cecilia Diniz Behn, Colorado School of Mines, recognized by the SIAM Activity Group on Dynamical Systems. It is especially rewarding to receive this honor for our recent work carried out with the talented young female mathematicians who have been training with us. I hope that this award inspires confidence in them and in other young female mathematicians as they pursue careers in mathematics.

Q: Could you tell us about the research that won you the award?

A: Mathematical models of physiological sleep-wake networks describe sleep-wake regulation by simulating the activity of neuronal populations that promote the states of wake and sleep, and the modulation of these populations by the homeostatic sleep drive and the 24-hour circadian rhythm. Motivated by changes in sleep behavior during early childhood, we are interested in how variations in the homeostatic sleep drive and the circadian rhythm generate developmental transitions in sleep-wake patterns, such as the transition from napping to non-napping behavior. In this paper, we analyzed bifurcations of solutions in a sleep-wake regulation model called the sleep-wake flip-flop. Since the model is piece-wise smooth, we implemented a suite of dynamical systems tools to detect and classify bifurcations of solutions. Specifically, we leveraged fast-slow decomposition to reveal stable and unstable manifolds that dictate trajectory flows. 

Based on these manifolds, we defined and computed circle maps for the timing of sleep onsets relative to the phase of the circadian rhythm drive. Identifying the variation of fixed point solutions on the circle maps as homeostatic and circadian drives were varied allowed characterization of the types and sequences of bifurcations as different stable solutions lost and gained stability. We found that the average daily number of sleeps exhibits a period adding sequence as the homeostatic time constants were reduced, and that the temporal circadian profile influenced the number of observed solutions in the sequence. Generally, our multipronged approach provides an alternative analysis method for describing bifurcations in high-dimensional, non-autonomous piecewise-smooth systems.

Q: What does your work mean to the public?

A: The influence of sleep and circadian rhythms to human health is becoming increasingly recognized. For example, sleep disruption and desynchronization of internal circadian rhythms with environmental or behavioral schedules is linked to many disease states. With our modeling work, we hope to increase understanding of proposed physiological mechanisms governing sleep-wake behavior and how light or behavioral schedules influence the interactions of sleep and circadian processes. Better understanding of how these processes respond to perturbations may eventually lead to therapies and interventions that can mitigate adverse effects of our 24/7 lifestyles and environments.

Q: What does being a member of SIAM mean to you?

A: I’ve been a SIAM member since I was a graduate student. Over the years, publishing in SIAM journals and participating in SIAM conferences have been integral to my research and its progress. Recently, I’ve been happy to give back to SIAM by being involved in the SIAM Committee on Programs and Conferences (2011-2016) and serving as Chair of the SIAM Activity Group on Life Sciences (2019-2020). It’s also been rewarding to help my trainees get involved in SIAM through organizing conference minisymposia and watching them build their own networks in the SIAM community. 

Yoshiki Kuramoto

Dr. Yoshiki Kuramoto, Kyoto University, will deliver the 2023 Jürgen Moser Lecture. Dr. Kuramoto was selected for his many pioneering contributions, with far-reaching impact, to the understanding of emergent phenomena in nonlinear systems, especially for oscillatory dynamics, synchrony, chemical turbulence, and spatio-temporal chaos. Dr. Kuramoto’s lecture is titled “Exploring the World of Coupled Oscillators” and will be presented at the 2023 SIAM Conference on Applications of Dynamical Systems (DS23) on Sunday, May 14 at 8:35 p.m. PT. 

The SIAM Activity Group on Dynamical Systems (DS) awards the Jürgen Moser Lecture every two years to an individual who has made distinguished contributions to nonlinear science. The term “nonlinear science” is used in the spirit of the SIAM Activity Group on DS conferences. Specifically, it includes dynamical systems theory and its applications as well as experiments, computations, and simulations.

Dr. Kuramoto was a student in the physics department of Kyoto University where he received his Ph.D. in physics in 1970. He then moved to Kyushu University and obtained an Assistant Professorship, where his major achievements were recognized with the naming of the Kuramoto-Sivashinsky equation and the making of the Kuramoto model. Dr. Kuramoto served as a professor at Kyoto University from 1981 until retiring in 2004. Subsequently, he held several academic positions, including Specially Appointed Professor of Hokkaido University and guest professor at the Mathematical Institute of Kyoto University. Through the majority of his academic career, Dr. Kuramoto’s primary focus was the dynamics of coupled oscillator systems, such as the pattern formation of self-oscillatory fields and synchronization of oscillator assemblies, and the theory of dynamical reduction as a tool for these studies. He was awarded the Asahi Prize in 2005 for his pioneering research on the nonlinear model of synchronization phenomena.

Q: Why are you excited to receive the award?

A: Since the science of coupled oscillators is a field still developing rapidly, I would be happy if my acceptance of the award attracts further interest in this field, particularly from young researchers.

Q: Could you tell us about the research that won you the award?

A: The discovery of the Kuramoto-Sivashinsky equation was partly a result of my erroneous speculation that the observed wave pattern in a spontaneously oscillating Belousov-Zhabotinsky reaction might be a result of some kind of instability occurring to a uniformly oscillating medium. Regarding the proposal of the Kuramoto model, the strongest motivation of this work came from A. Winfree’s 1967 paper. These two model equations were derived through a phase reduction of the complex Ginzburg-Landau (GL) equation and its variant. Therefore, my successful derivation of the complex GL in 1974 may have been a decisive step for my research career thereafter.

Q: What does your work mean to the public?

A: Since my theoretical contribution to the science of coupled oscillators, especially to the study of synchronization phenomena, is of a relatively fundamental level of nonlinear science, I do not expect such a direct impact of my work on the public. However, as long as the synchronization phenomena themselves are concerned, they are widespread around us, as implied by their vital significance for our life processes and their technological applications. So, they are recently attracting a lot of interest from the public. For instance, the popular science book on synchronization which I published in Japanese several years ago had quite a large readership.  

blog comments powered by Disqus