Madison Chaos and Complex Systems Seminar

Spring 2018 Seminars

All seminars are Tuesday at 12:05 pm in 4274 Chamberlin Hall except as noted. Refreshments will be served.

Short List
Join us for lunch during the summer on the Memorial Union Terrace at noon each Tuesday, starting May 8th!


January 23, 2018

What Have We Learned From Gravity?

Georgy Hrabovsky, UW Department of Physics

Aristotle started the ball rolling. Our ideas about gravity have evolved ever since. We will take a whirlwind tour of how theories of gravity have changed as our mathematical technique, observations, theoretical sophistication, and society have changed. Far from being settled, this most obvious of natural forces is anything but well understood.

January 30, 2018

Stochastic optimization: Making complex design, planning, and operation decisions in the face of uncertainty

Jim Luedtke, UW Department of Industrial Engineering

Stochastic optimization is a branch of mathematical optimization concerned with helping make design, planning, and operation decisions in the face of uncertain outcomes or data. Example applications of stochastic optimization include: planning power generation in systems with uncertainty in wind outputs and rainfall (which effects hydro-reservoir levels); deciding order quantities at a retailer with uncertain customer demands; and making financial investments without knowing the returns the different investment options will yield. I will provide an overview of the field stochastic optimization, with a bias towards topics related to my research.  I will focus on discussing different types of models and when they might be useful, and, time permitting, will overview some of the solution approaches.

February 6, 2018

Prions and the environment

Joel Pedersen, UW Department of Soil Science

Prions are the enigmatic etiological agents of transmissible spongiform encephalopathies (TSEs), a class of fatal neurodegenerative diseases affecting humans and other mammals. The pathogenic prion protein is a misfolded form of the host-encoded prion protein and represents the predominant, if not sole, component of the infectious agent. Environmental routes of TSE transmission are implicated in epizootics of sheep scrapie and chronic wasting disease of deer, elk, and moose. Soil is the most plausible candidate for preserving prion infectivity in the environment. We have investigated prion attachment to and detachment from inorganic and organic soil particle surfaces and examined the effect of association with specific soil constituents on disease transmission. Interaction of prions with some phyllosilicate mineral surfaces is remarkably strong. Interestingly, rather than diminishing bioavailability, attachment to such particles enhances disease transmission. This finding suggests an explanation for environmental disease transmission despite the presumably low levels of prions shed by infected animals. Our results to date suggest that prions released into many soil environments are preserved near the surface in a bioavailable form, likely perpetuating prion disease epizootics and exposing other species to the infectious agent. The high stability of prions observed in other contexts may contribute to their survival in the natural and engineered environments.

February 13, 2018

Complexity in gene editing outcomes with defined CRISPR nanoparticles

Kris Saha, UW Department of Biomedical Engineering

Writing specific DNA sequences into the human genome is challenging with gene-editing reagents, since most of the edited sequences contain various imprecise insertions or deletions of DNA sequence. Only a minor of sequences produced contain the desired sequence. We developed a modular RNA aptamer-streptavidin strategy, termed S1mplex, to complex CRISPR-Cas9 ribonucleoproteins with a nucleic acid donor template. In human cells, tailored S1mplexes increase the ratio of precisely edited to imprecisely edited alleles up to 18-fold higher than standard gene-editing methods, and enrich cell populations containing multiplexed precise edits up to 42-fold. Topics related to the complexity seen in the sequence outcomes will be discussed. Advances in reducing the complexity of sequence outcomes could greatly reduce the time and cost of in vitro or ex vivo gene-editing applications in precision medicine and drug discovery and aid in the development of increased and serial dosing regimens for somatic gene editing in vivo.

February 20, 2018

Kim Krautkramer, Wisconsin Institutes for Discovery

Interactions between environment and host epigenome: metabolism, the microbiota, and hibernation

How do environmental stimuli/insults signal to the mammalian epigenome and what role do the microbiota play in this process? This talk will highlight recent and ongoing collaborative work aimed at understanding how environmental factors impact the host epigenome in mammals, including diet, maternal environment, and seasonal changes in body composition and metabolism in hibernators. We explore these questions using a variety of methods, including mass spectrometry, high throughput sequencing, and both wild-caught and gnotobiotic animal models.

February 27, 2018

Thoughts on drumlins, a major component of Wisconsin's glacial landscape

David Mickelson, UW Department of Geology

Thousands of cigar-shaped elongate hills dominate the landscape to the east and north of Madison. Produced by glaciers 15,000 to 25,000 years ago, they have a range of heights from meters or less to several hundred meters and have distinctly different length-to-width ratios in different areas. All are parallel to former ice flow direction. They are composed of sediments deposited by the last glaciation, but many also contain older deposits. Why are they so abundant in Wisconsin, but absent from the huge areas covered by the last glaciation in most of Illinois, Indiana, Iowa, and Ohio?

March 6, 2018

Wada basins and distributed fields of determination

Steve Ridgely, UW Department of Asian Languages and Cultures

Wada Basins are spaces containing three or more subregions in which each boundary is shared by all subregions. This topological concept, attributed to Takeo Wada and described by his Kyoto University colleague Kunizō Yoneyama in 1917, has gained an afterlife through application to complex systems in which a “basin” of initial conditions might be said to exhibit the “Wada property.” The topological form of a Wada basin would seem to map determination across a distributed field such that indeterminacy would be inherent to the spatial form, well beyond a metaphor for systems about which we have insufficient information.

March 13, 2018

Speech as a dynamical system

Ben Parrell, UW Department of Communication Sciences and Disorders

The act of speaking is one of the most complex motor behaviors humans produce: a set of over 100 muscles must be precisely coordinated in space and time to produce rapid movements (50-300 ms) at a high rate (roughly 40 unique sounds per second). How can we control such a complex system with enough precision to produce intelligible speech? This talk will present the view that speech is a hierarchical dynamical system, with control needed only at a high-level (of speech goals or tasks) rather than a system where all muscle activations are controlled centrally. I will explain how this approach can explain speech phenomena in various languages, and show a preliminary sketch of how such a system could be instantiated in the brain.

March 20, 2018

What makes math hard? Hint: It’s not the math

Mitchell J. Nathan, UW School of Education

I present findings on mathematical intuitions and invented solution strategies to challenge well-entrenched notions that mathematics is hard to learn. I consider how Expert Blind Spot shapes the framing of Math-As-Hard that can alienate learners from entering a field of great creativity and enormous societal relevance, and I challenge the audience to reflect on who benefits from this framing (look around the room), the implications for the future of science and public policy, and what we all can do about it.

April 3, 2018

The Invention of Public Radio at the UW--Madison Physics Department, 1917-1919

Jim Reardon, UW Department of Physics

From April 1917-March 1919 Prof. Earle Terry of the UW-Physics Department was able to continue research in wireless voice telephony--what we would now call AM radio--while all through the rest of the world, non-military radio research was halted by World War I. By the end of this time, he and graduate student Cyril Jansky were able to make triode vacuum tubes capable of dissipating more than 50 W, allowing his station 9XM to transmit voice intelligible at a range of 130 miles. Terry and Jansky freely shared their work with researchers at other Universities, which contributed to the proliferation of College and University radio stations in the 1920's, the ancestors of what we now know as public radio. The talk will feature a replica of the original 9XM transmitter, constructed as part of the celebration of the centennial of the Ingersoll Physics Museum.

April 17, 2018

Are modern psychological and social behavior investigators missing a boat developmental neuroscience could help them catch?

Bernard Z. Friedlander, Department of Psychology, University of Hartford

Large bodies of research with people of all ages tend to confirm that children who perform better on tests of delayed gratification (DG) tend to do well in life, while those with limited capacities for DG as children do less well in the progress of their lives.

This paper presents the possibility that DG and related behavioral realities represent critical processes in individual psychological development. These processes are open to new vectors of understanding based on new thinking
about the autonomic nervous system and developmental neuroscience. New ways of thinking about old problems offer tantalizing possibilities for new research.

April 24, 2018

Some half-baked philosophy of mathematics

Moe Hirsch, UW Department of Mathematics