Madison Chaos and Complex Systems Seminar

Spring 2011 Seminars

All seminars are Tuesday at 12:05 pm in 4274 Chamberlin except as noted.

Short List

Join us for lunch during the summer on the Union Terrace at noon each Tuesday, starting May 10th!


January 18, 2011

How the brain makes up the mind: The biology of personality and decision-making

Mike Koenigs, UW Department of Psychiatry

One of the most impressive functions of the human brain is the navigation of a complex and dynamic social environment.  Humans are clearly not 100% 'rational' creatures whose behaviors are strictly determined by universal social, moral, or economic laws.  We each have our own particular set of beliefs, values, attitudes, fears, desires, and temperament -- in short, we all have unique personalities.  At some level, all of human behavior can be viewed as an output of the human nervous system, so is there a brain area that controls our individual personalities?  If so, where is it and how does it work?  In this talk I will describe studies of neurological patients who have undergone dramatic changes in personality as a result of their brain injuries.  These studies have identified a particular area of the brain -- the ventromedial prefrontal cortex -- that is especially critical for controlling emotion, decision-making, and social behavior.  I will describe my research with these patients, as well as how knowledge gained from this work may be applied to understand illnesses such as depression, anxiety, and psychopathy.

January 25, 2011

Chaos in Easter Island ecology

Clint Sprott, UW Department of Physics

Easter Island in the South Pacific, with an area the same as the city of Madison, is one of the most remote inhabited spots in the world, located over 2000 km from its nearest inhabited neighbor. As such, it offers an opportunity to study a relatively simple ecology with possible global implications. Its human population is thought to have grown to a peak of about 10,000 during the millenia leading up to the year 1700, and then to decline to a mere 110 by the year 1877. The usual explanation is that the inhabitants overconsumed the abundant palm trees that were used for cooking, housing, fishing boats, and for transporting the large stone statues for which the island is famous, leading to starvation, war, disease, and possibly cannibalism. In this talk, I will describe some recent simple mathematical models for the rise and fall of their civilization and will show that one of these models has chaotic solutions, not previously known.

This talk is available as a PowerPoint Presentation.

February 1, 2011

Spatial and temporal variability in groundwater chemistry: Is there any such thing as a "representative" sample?

Jean Bahr, UW Department of Geoscience

The dissolved constituents found in groundwater have been of interest for over two centuries. In fact many of the early developments in analytical chemistry were motivated by requests from physicians who were interested in the composition of springs and spas that had presumed therapeutic benefits. More recently, public attention to groundwater chemistry has focused on constituents that are associated with health hazards such as arsenic and hexavalent chromium. In addition to its relevance to human health, water chemistry data provide hydrogeologists with clues to the complex subsurface structures and processes that control groundwater flow and water-rock interactions. A major challenge to interpreting these data is posed by the spatial and temporal variability of measured concentrations. This talk will discuss several case studies in which high resolution sampling and tracer experiments have been used to document the effects of complex flow fields and subsurface reactions on the chemical signatures we observe in groundwater samples.

February 8, 2011

How video games model agency in complex systems

Rich Halverson, UW School of Education

Simulations have become standard tools for research in dynamic, complex systems.  Yet simulations often struggle to model how individuals make choices in such systems, often by substituting estimated probability models for direct observation of actor interaction.  Contemporary immersive video games provide models for how researchers can study how actual actors interact with complex systems. In today's discussion, I will review several research approaches to understand the cognitive and socio-cultural aspects of player-videogame engagement, and discuss how the development of the next generation of video-games can outline a new form of observational research on complex system interaction.  

Richard Halverson, Ph.D., is Associate Professor of Educational Leadership and Policy Analysis at the University of Wisconsin School of Education. He is co-founder of the Games, Learning and Society research group, and Associate Director of the Education Research Challenge Area of the Wisconsin Institutes for Research. He was co-author (with Allan Collins) of Rethinking Education in the Age of Technology: The Digital Revolution and Schooling in America.

February 15, 2011

How I stopped worrying and learned to love Global Warming

Jim Blair, Milton and Edgewood College
  1. Warmers vs. Skeptics: who are the skeptics?
  2. What are we doing about Climate Change?
  3. What would we do if we were serious?
  4. The sunny side of Climate Change.

February 22, 2011

Chaos in the three-body Coulomb problem

Vladimir Zhdankin, UW Department of Physics

The three-body problem is one of the most famous examples of a chaotic system. In the traditional case, the goal is to determine the motion of three massive bodies interacting through Newton's law of universal gravitation. Similarly, the goal in the three-body Coulomb problem is to determine the motion of three electrically charged particles interacting through Coulomb's law. Among other things, this can be used as a classical model of the helium atom (where the effects of quantum mechanics are neglected). This talk will describe and present some numerical solutions to the three-body Coulomb problem. The general solution has a short transient chaotic phase until one particle is ejected from the system, but special initial conditions are found to give chaotic orbits that remain bounded.

March 1, 2011

Wind turbine generators: The basics

Mitch Bradt, program director, Department of Engineering Professional Development

During the years 2005 - 2009, US wind energy installations experienced growth annual growth rates of 20-45% capacity increase. In the talk, the speaker will give a presentation on some of the fundamental technical background on this maturing energy source. This will include the mechanical and electrical sides of the energy conversion process, a sample of Annual Energy Production estimates as well as the concept of Capacity Factor. We'll take you to the top of a turbine to see the equipment inside--hold onto your hat, it's 100 meters to the top! Then we'll climb back down and follow the electrons to the bulk transmission grid, onto the the distribution grid, and finally to your house to power your lights, ovens, and flatscreens.

March 8, 2011

Psychotherapy is remarkably effective-- For the reasons patients (but not scientists) know

Bruce Wampold, UW Department of Counseling Psychology

Randomized clinical trials have produced sufficient evidence to conclude that psychotherapy is remarkably effective-- more effective than many accepted medical procedures. However, the research evidence seems to indicate that widely divergent approaches to psychotherapy (e.g., cognitive, behavioral, and psychodynamic) are equally effective, casting doubt on the "scientific" explanations that are the bases of these treatments. Indeed, there is little evidence to support the treatment mechanisms purported to explain how psychotherapy works. Instead, there is much research evidence that there is significant variability among clinicians in terms of benefits, regardless of the treatment approach used. We are beginning to understand the characteristics and actions of effective therapists-- and these involve developing a collaborative working relationship with the patient, providing an acceptable (but not necessary scientifically correct) explanation for the distress, and inducing healthy actions.

March 22, 2011

The hydroecology of meadows in the Sierra Nevada, CA

Steve Loheide, UW Department of Civil and Environmental Engineering

Meadows area critical components of the Sierra Nevadan landscape providing local productivity, biodiversity, and hydrologic buffering of watershed processes. However, overgrazing, logging, and road/railroad construction have impaired the ecologic and hydrologic function of meadow systems altering the ecosystem services they provide. This presentation will focus on the interrelationships between groundwater and soil water availability, plant water use, and vegetation patterning in meadow ecosystems.

March 29, 2011

Why does a molecular spectroscopist care about chaos (continued)?

Ned Sibert, UW Department of Chemistry

Molecules are made up of atoms held together by chemical bonds.  Excitation of these bonds causes that atoms to move with respect to one other.  This motion can lead to chemical reaction, isomerization, and a range of other important chemical properties.  For this reason, understanding the dynamics that occurs upon laser excitation is of fundamental interest to chemists.  At low energies, where the underlying classical dynamics of the molecular vibrations is regular, this assignment is relatively straightforward.  At higher energies, however, the underlying classical dynamics explores larger regions of phase space and may be chaotic.  Early work by Chirikov allowed chemists to make connections between vibrational resonances and chaos theory.   In this talk, I will review research in this area and then describe some intriguing features of quantum localization due to interference of homoclinic circuits.

This talk is available as a PowerPoint Presentation.


A new dynamical mechanism for major climate shifts

Anastasios Tsonis, Department of Mathematical Sciences, UW-Milwaukee

We construct a network of observed climate indices in the period 1900–2000 and investigate their collective behavior. The results indicate that this network synchronized several times in this period. We find that in those cases where the synchronous state was followed by a steady increase in the coupling strength between the indices, the synchronous state was destroyed, after which a new climate state emerged. These shifts are associated with significant changes in global temperature trend and in ENSO variability. The latest such event is known as the great climate shift of the 1970s. We also find the evidence for such type of behavior in three climate simulations using a state-of-the-art model. This is the first time that this mechanism, which appears consistent with the theory of synchronized chaos, is discovered in a physical system of the size and complexity of the climate system.

April 12, 2011

The search for the monsters at the centers of galaxies

Andy Sheinis, UW Department of Astronomy

The past decade has given rise to conclusive evidence that all galaxies harbor a super-massive black hole in their cores.  A black hole is a massive body whose surface gravity is so great that light cannot escape its gravitational pull.  A growing understanding of the connection between galaxies and their central black holes has emerged that relates some of the properties of the black hole, whose gravity influences only the central 1/10,000 of the galaxy, to the global properties of the entire galaxy.  Furthermore the latest galaxy formation and evolution theories require the input of energy from the black hole into the galaxy to achieve the size, shape and number density of the galaxies we observe today.  These facts suggest that the growth mechanisms of the black hole and galaxy must be connected. However, details of the physical processes behind this connection are not yet understood.   I will present an overview of the status of the field and then discuss my research to understand the nature of some of the most massive of these objects that are in the process of consuming massive amounts of matter from their host galaxies. These objects are Quasi-Stellar Objects or QSO’s, which shine brightly in the sky due to the excess gas that escapes their feeding process.

April 19, 2011

Response of pollen in Devils Lake WI to the Younger Dryas event
(in memory of the late Clarence Clay)

Lou Maher, UW Department of Geoscience

When European botanists studied fossil leaves, seeds, and pollen in late-glacial and postglacial sediments, they noted evidence that postglacial warming was interrupted during two intervals with the reappearance of leaves and fruits of Dryas octopetala (Mountain Arvins). Today the plant occurs in restricted areas of northern Scandinavia, Ireland, and northern Russia, usually on high ground, rock ledges and on calcareous soils. These two cooler intervals were named the Older Dryas and the Younger Dryas. The Younger Dryas cold interval existed from about 12,900 to 11,600 years ago. Sediment cores were taken from Wisconsin’s Devils Lake during the winters of 1978 and 1993. These were sampled and processed for pollen analysis. The pollen taxon abundances were measured both as their percentage of the total pollen sum and as pollen influx (pollen grains per cc/year). Our Chaos presentation deals with the changes in the Devils Lake core during Younger Dryas time.

April 26, 2011

Paradise lost? Teaching about climate change in the Great Lakes Region

Dolly Ledin, UW Center for Biology Education

This unique outreach and education project brings together the compelling evidence of science, the interpretive talents of professional artists and the skills of educators to engage communities in learning about climate change in the Great Lakes region. Artists, scientists and educators collaborated to create a traveling multi-media exhibit, educational events and website for teachers.

May 3, 2011

GPU accelerated simulations of chaotic PDEs

Jon Seaton, UW Department of Physics

It is well known that chaos exists in systems of ordinary differential equations (ODEs), however, the study of chaos in partial differential equations (PDEs) remains rather new and unexplored. This is in part due to the computational resources needed to accurately simulate such systems. However, recent improvements of graphics processing units (GPUs) for use in general computing may provide a fast and economical way to solve complex systems such as PDEs. This talk will discuss the development of an algorithm which both numerically solves and determines the existence of chaos in nonlinear PDEs while utilizing the multiprocessor architecture of the GPU. This new method will aid in our search for simple examples of chaotic PDEs.