Speaker series WN2024

Feb. 1st, PROF. myron campbell

Title: Sponsored Research - the Compact Between the Federal Government and Universities

Abstract: The compact between the Federal Government and Universities to perform research has been in place for 80 years.  This talk will describe the history behind the establishment of the federal research funding model and the current state of federal research.

feb. 15th, PROF. david lubensky

Theoretical Biophysics

Title: The physics of inflationary embryology: Growth, size, and precision, from cells to organisms

Abstract: One of the enduring mysteries of biology is how cells and organs know to stop growing at the correct size (and how those sizes are coordinated so that animals can retain their correct proportions).  Here, I will discuss several studies that, in different ways, address the physics of how organ size is set and how precisely it can be controlled.  First, I will introduce a simple phenomenological framework that allows one to consider tradeoffs between noise in the actual growth process and in a system's internal estimate of its own size.  I will show how this framework places a bound on the size precision of individual bacterial cells and analyze data from recent experiments to show that, at least in some circumstances, the measured precision is very near this bound.  Then, I will extend the framework to consider how sizes can be coordinated by chemical signals, for example between contralateral organs like the left and right wings of a fruit fly, and show that theory severely limits how well this can be done.  Finally, I will study the noisy dynamics of the growth of multi-cellular tissues in the presence of various feedback laws, finding that only certain forms of mechanical feedback can specify a unique organ size.  Along the way, I will observe that growing tissues tend to show power law density correlations, reminiscent of those also observed in models of the early universe.

Mar. 14th, PROF. gus Evrard

Title: Living the Transistor Disruption

Abstract: Transistors and the digital computers built from them have dramatically changed — “disrupted” in Silicon Valley parlance — the world in myriad ways.  In this talk I will examine how those disruptions have affected my career, with topics ranging from computational cosmology to computing education in the College of LSA to supporting AI at the University of Michigan. 

APRIL 11TH, JOSH SPITZ

Title: Using Ancient Rocks to Look for Atmospheric Neutrinos

Abstract: Earth is constantly being bombarded by cosmic rays, energetic particles from the cosmos. These particles provide a window on both the nature of their astrophysical sources and into multiple aspects of particle physics and cosmology. Recently, it has been pointed out that the history of the cosmic ray rate over the past ∼1 billion years can be measured using atmospheric neutrino (produced readily in cosmic ray interactions with the Earth’s atmosphere) induced imprints in minerals, or “paleo-detectors”, buried deep beneath the Earth’s surface. The time evolution of cosmic rays provides a unique window into the history of the Earth, including aspects of the geo- and helio-magnetic fields, the atmosphere, and the trajectory of our planet through the Milky Way galaxy, noting that the Earth goes around the galaxy once every 230 million years. In this talk, I will discuss the overarching paleo-detector concept in the context of a number of physics studies, and our group's pursuit of measuring atmospheric neutrinos in these ancient rocks.