Activity recorded from neurons in the brain often looks random or chaotic. How do we make sense of the world and produce precisely controlled responses when so much of the activity in our brains is chaotic? This talk will show how brain circuits can switch between chaotic and well-controlled patterns of activity, illustrating these points with computer demonstrations of network models. This talk will also discuss how chaotic activity may be useful for a healthy brain function and demonstrate what goes wrong when activity is insufficiently chaotic.
Are we ready to come face to face with our innermost genetic secrets? Will this knowledge help us make wise choices? Can we trust ourselves and others with safeguarding this most potent knowledge? Be part of the live studio audience for this special edition of TVO's Agenda with Steve Paikin.
Using results from models of the atmosphere/ocean/sediment carbon cycle, the impacts of fossil-fuel CO2 release will be examined including the effect on climate many thousands of years into the future, rather than for just a few centuries as commonly claimed. Prof. Archer will explain how aspects of the Earth system, such as the growth or melting of the great ice sheets, the thawing of permafrost, and the release of methane from the methane hydrate deposits in the deep ocean, take thousands of years to respond to a change in climate.
Sixty-five million years ago dinosaurs ruled the warm Cretaceous Earth. Without warning, this world was swept away forever by the impact of an asteroid about 15 km in diameter, leaving a huge scar now called the Chicxulub crater in Yucatan, Mexico. This catastrophe set the stage for the ascendance of our own biological group, the mammals. Although the fact of this impact is now established beyond doubt, the precise means by which an impact could wipe out such a large fraction of the Earth\'s inhabitants is not fully understood.
Hollywood movies about aliens abound, but do they really exist? The real scientific search for evidence of life, and particularly intelligent life, elsewhere in the cosmos is just as exciting as the reel version, and a lot more logical. So far, there is life-as-we-know-it to guide our speculations and observations. But a new appreciation for the tenacity of life, a growing respect for the world of microbes, and new search technologies involving observatories and spacecraft are rapidly expanding our viewpoint. Many expect surprises.
The scientific approach to consciousness is a relatively new pursuit, but it has already revealed some startling facts about the cavalcade of feelings, images and thoughts that stream through our heads every waking moment. Jay Ingram will present some of the most surprising of these in a talk based on his best-selling book, Theatre of the Mind. Jay Ingram is the author of several bestselling books, including The Science of Everyday Life, The Barmaids Brain and The Velocity of Honey.
Our ability to understand the physical world has to a large extent depended on the existence of emergent properties, and the separation of scales that permits effective field theory descriptions to be useful. Exploiting this fact, we can construct minimal models that enable efficient calculation of desired quantities, as long as they are insensitive to microscopic details. This works in many instances in physics, and I give some examples drawn from the kinetics of phase transitions mediated by topological defects.