Jairo Diaz, Rochester Institute of Technology
Yi Sun, University of Chicago
Kate Bonnen, New York University
Keith Hawkins, University of Texas at Austin
Shana Caro, University of Texas at Austin
The third edition of the Simons Society of Fellows Alumni Symposium came together in October 2021, as we slowly began to venture to indoor events, our immune systems bolstered by vaccines against COVID-19. We were supported by Meghan Fazzi, Melanie Shiree, and the fantastic support team at the Simons Foundation. Attendees included junior fellows in their first and second years who had not met in person and many alumni who were invited to present their work in the Ingrid Daubechies Auditorium. A few fellows attended on Zoom. All who attended in person marveled on how the prior year had changed our lives, and for many of us, this event was a scientific and a social highlight.
Unlike the past alumni symposia, which revolved around a theme, this year’s schedule was entirely focused on the alumni fellows who took advantage of the time and flexibility offered them to discuss their recent work. We had five speakers, and their talks reflected the diversity of fields that the junior fellows come from and elicited a lot of interaction. They highlighted the support that the Simons Foundation provided and some of the fantastic collaborators they found among the society of fellows.
Jairo Diaz (class of 2015) spoke about harnessing the unique specificity and strength of DNA to design structures in colloids. The beautiful symmetric structures this tool allows have a range of applications in assembly and novel materials. Jairo teased that we might one day build invisibility cloaks from such materials!
Yi Sun (class of 2016) presented a mathematical method of signal recovery from noisy data and applied it to images taken of a protein by a cryo-electron microscope. They found that the orbit of rotation shapes the optimization properties of the landscape of estimation. At the Q&A, Rosemary Cater (class of 2018), our expert in structural biology, taught us the intricate nature of taking cryo-electron microscopy images from personal experience. Kathryn Bonnen (class of 2019) showed us landscapes of another kind.
In data gathered from humans on hikes, she illustrated how eye movements and body motions are coordinated to support movement on different terrain. Bonnen next spoke passionately about a new model for neuroscience education as one of the founders of Neuromatch Academy, which conducts online summer courses with teaching assistants and students recruited across many countries and time zones. Keith Hawkins (class of 2016) took us on a galactic archaeology hike, tagging stars to deduce their origins and relationships with one another. Collecting detailed data on the chemical composition, position, and movements across space, he finds connectedness between stars that may have slowly drifted apart.
Shana Caro (class of 2017) exploited the connectedness between parent and offspring to ask questions about the evolution and meaning of communication signals. Using a model of begging in nestlings in different bird species, she dissected the purpose begging serves beyond signaling immediate hunger in the nestling and how it drives parental care and bond. Caro reflected on her newly formed collaboration with Krista Perks (class of 2018) and the importance the society had, not only on our personal development, but on pushing the boundaries of science into seemingly remarkable directions.
The Society of Fellows Alumni Symposium brings fellows together at a time when our societal bonds are challenged and it reinforces in us our love for science, society, and each other.
Wednesday, October 6
9:30 AM JAIRO DIAZ | Multipotential Colloids 11:00 AM YI SUN | Maximum likelihood for high-noise group orbit estimation and single-particle cryo-electron microscopy 1:00 PM KATE BONNEN | Seeing in Motion 2:30 PM KEITH HAWKINS | Galactic Archaeology : Uncovering the Story of Our Home with Stellar Fossils 4:00 PM SHANA CARO | The evolution of (dis)honesty and parental care(lessness)
Abstracts and Slides
University of Texas at Austin
Galactic Archaeology: Uncovering the Story of Our Home with Stellar Fossils
What are the processes that govern the formation, evolution and assembly of galaxies across cosmic time? This question is among the most fundamental in modern astronomy, yet the answer still eludes us to this day. The Milky Way and its local group is the optimal laboratory for answering the questions of galaxy formation because it is one of the only systems to date where we can obtain detailed and precise data on the positions, motions and chemical composition for billions of individual stars. This is the holy grail of galactic archaeology. Recent large-scale spectroscopic surveys have enabled a detailed observations of the Milky Way. In this talk, Hawkins will discuss he current work in galactic archaeology and how data from these industrial surveys in stellar astronomy have been used to dissect the structure of our galaxy. He will also explore the future of galactic archaeology through chemical cartography.
Jairo A. Díaz
Rochester Institute of Technology
Millions of microscale ‘building blocks’ can self-assemble into much larger structures capable of creating rich emerging properties (e.g., cells forming tissues, particles forming crystals). However, decorating the surface and controlling the shape of a simple microscale block remain challenging, requiring nanoscale precision to efficiently encode self-assembly instructions. The complexity and cost of such tasks increase when extended to millions of building blocks.
Díaz will present a novel tool where short DNA strands are used to both design shape and program binding information for colloids in bulk. The molecular precision of DNA design opens a window for rapid nanoscopic decoration, where deformations and symmetries can be programmed with ‘molecular’ resolution. Patch symmetries and DNA sequence are sorted in the liquid phase, while controlled transition to the solid phase freezes in the DNA designs for further assembly. This method enables the production of monodisperse DNA-coated faceted particles in the order of minutes.
The novel multi-DNA patchy particles hold promise to rapidly access metastable regions in phase diagrams, offering unique opportunities to extend the number of realizable self-assembled structures.
New York University
Seeing in Motion
Humans spend much of their lives in motion, acting in the world. Thus, our visual systems must support visual perception during self-motion and visual perception for self-motion. Advances in mobile-eye-movement and body-motion tracking have enabled recordings of how we move our eyes and bodies during self-motion in natural environments. Furthermore, such recordings give us unprecedented access to the patterns of light that actually fall on our retinae during self-motion. In this talk, Bonnen will use these data to 1) describe how humans coordinate their eye movements and body motion to support stable gait patterns in difficult terrain, and 2) examine the natural statistics of retinal motion and present a set of predictions that these statistics make for the differences in retinal-motion processing across the visual field.
Maximum likelihood for high-noise group orbit estimation and single-particle cryo-electron microscopy
This talk will focus on the problem of recovering an unknown signal from noisy observations subject to random and unknown rotations, a model motivated by applications to single-particle cryo-electron microscopy (cryo-EM). After describing several historical approaches to this problem, Yi will present recent results on the non-convex optimization landscape of maximum likelihood estimation, the most commonly used method for this problem. In particular, these results show that the optimization properties of the landscape in the high-noise regime are determined by the algebraic structure of the rotation group.
This is talk is based on joint works with Zhou Fan, Roy Lederman, Tianhao Wang, Yihong Wu and Sheng Xu.
The evolution of (dis)honesty and parental care(lessness)