Winter 08

The Winter 2008 Lectures

Sunday, January 20, 2008

Unlocking the Mystery of Mass: Searching for the Higgs Boson Particle

Wendy Taylor, Ph.D., Canada Research Chair in Experimental Particle Physics, Dept. of Physics and Astronomy, York University

Why is the photon massless? Why is the top quark as heavy as 175 protons? How can electromagnetic phenomena and radioactive decay be due to the same force? Physicists on the new ATLAS experiment hope to answer these questions and more with the discovery of the elusive Higgs boson, the Holy Grail of particle physics for over thirty years. When the Large Hadron Collider at the CERN Laboratory in Geneva, Switzerland starts operation in spring 2008, it will expose physics never seen before. The ATLAS experiment will either discover the Higgs boson or something else even more intriguing. In this talk, I will discuss the motivation for postulating the Higgs boson, describe the LHC and the ATLAS experiment, and explain how the Higgs boson could be detected, giving you a flavour of the challenges and rewards of “big science” along the way.

Co-sponsor Royal Astronomical Society of Canada - Toronto Centre

Sunday, January 27, 2008

Brain Rewards: From Singing Mice to Human Diseases

John Yeomans, Ph.D., Departments of Psychology and Cell and Systems Biology, U of T

Mice communicate by complex ultrasonic songs. Males sing to females for mating, females sing to females for food, and mouse pups sing when separated from their mothers. These songs tell scientists the emotional states of rats and mice, and have been linked with laughter, speech, happiness and sadness in humans. By deleting or adding single genes in mice, the genes needed for pleasure, social communication and perhaps language can be studied. In particular, we have deleted genes needed for the brain transmitters dopamine and acetylcholine to communicate messages for food, sex and drug rewards to brain neural circuits, as an approach to studying attachment, addiction and schizophrenia.

Sunday, February 3, 2008

Getting to the Root of Cancer

John E. Dick, Ph.D., Division of Cell and Molecular Biology, University Health Network, and Dept. of Molecular Genetics and Microbiology, U of T

Two fundamental problems in cancer research are identification of the normal cell within which cancer begins and identification of which cell type in the tumour is capable of sustaining the growth of that cancer. There is overwhelming evidence that virtually all cancers begin in a single cell (that is, they are clonal). However, what is becoming clear is that not every one of the cancer cells that make up the tumour mass is equally the same. There is now evidence that for most cancers, only rare cells within the cancer are responsible for keeping the cancer growing. These were first identified in blood cancers (leukemia). We called these cells leukemic stem cells (LSC). Most cells in a leukemia grow rapidly, but the LSC grow very slowly, but are still very powerful as they keep making more of the fast-growing leukemia cells. Because they grow so slowly they are resistant to most kinds of chemotherapy that are designed to kill the fast-growing cells. This can explain why leukemia can come back after treatment. So to truly get rid of the leukemia, you have to find ways of eliminating the LSC. It turns out that solid tumours also have these rare so-called Cancer Stem Cells (CSC) and there is much current work going on to understand the properties of these CSC and how they might escape therapy.

Sunday, February 10, 2008

Flying Through Storms: Greenland’s Impact on the Climate System

G. W. Kent Moore, Ph.D., Dept. of Chemical and Physical Sciences, U of T at Mississauga

Greenland has a major influence on the atmospheric circulation of the North Atlantic-Western Europe region, dictating the location and strength of small-scale weather systems around its coastal seas and directly influencing large-scale weather systems both locally and downstream over Europe. One can think of this sizeable 300-metre-high ice-covered barrier acting to deflect flow both over and around it with both local and remote consequences. In this talk, I will present the first-ever observations of the role that weather systems near southern Greenland play in the climate system that were collected with an instrumented research aircraft during February 2007.

Sunday, February 17, 2008

How did that Chemical that was Inside my Computer Get Inside of Me?

Miriam Diamond, Ph.D., Dept. of Geography; Dept. of Chemical Engineering and Applied Chemistry Centre for Environment,

U of T

Numerous synthetic chemicals have enabled us to live our relatively comfortable and convenient lives that include considerable technological sophistication. Some of these chemicals can inadvertently escape into the environment and enter us. Problems can arise and have arisen when the chemicals have the potential to act as toxins and when the chemicals are persistent. We will examine two classes of such chemicals -- polybrominated diphenyl ethers, that are used as flame retardants in electronic equipment and furnishings, and polychlorinated biphenyls, that were and are used in electrical equipment and other applications. We will trace the origin of these chemicals in various products and how they enter us via the indoor environment and our food.

Sunday, February 24, 2008

Sticky Fingers Sharpen Our Sense of Hearing -- Understanding the Causes of Deafness

Dorothea Godt, Ph.D., Dept. of Cell and Systems Biology, U of T www.zoo.utoronto.ca/dgodt/godthome.html

Some forms of deafness are hereditary, others are induced by the environment. In either case, the hearing loss is often caused by a disturbance of the finger-like structures that stick out from the surface of the sound receptors in our inner ear. Normally, these fingers are arranged like organ pipes and are held together by strings. Under the impact of incoming sound waves they bend like grass in the wind. This signals the sound receptor to send a nerve impulse to the brain, where the information is interpreted as sound. Any defect in the finger bundle disrupts the signalling process, and therefore the ability to hear. In recent years, much progress has been made in finding the molecules that are important to make and maintain the ‘sound fingers’ and are critical for preventing deafness. Mice and flies help us to decipher how these molecules work.

Sunday, March 2, 2008

Three Centuries of Leonhard Euler

Craig G. Fraser, Ph.D., Institute for the History and Philosophy of Science and Technology, U of T

www.chass.utoronto.ca/~cfraser

Leonhard Euler (1707-1783) was the greatest mathematician of the eighteenth century, occupying a position in mathematics analogous to that of Bach in music or Goethe in literature. Some fifty years after his death the French scientist François Arago wrote “Euler calculated without apparent effort, as men breathe, or the eagles sustain themselves in the wind.” The 300th anniversary of Euler’s birth has been marked by a resurgence of interest in Euler studies, with scholarly conferences held throughout the world to commemorate and to document his extensive contributions to mathematical science. We examine Euler’s career at the academies of Berlin and St. Petersburg and describe some of the innovations for which he is best known. Among these was his introduction of the function concept to formalize the diverse range of geometric forms employed by earlier mathematicians to represent relations among variables and constants. Euler’s vast labours in calculus-related parts of mathematics earned for him the historical title of “analysis incarnate.”

Co-sponsor The Fields Institute for Research in Mathematical Sciences

Sunday, March 9, 2008

Fun with Science - especially for kids 6 - 12

Russell Zeid, RCI Council member, educator

A lively hour that puts the “fizz” back in physics! Why do things do what they do? Discover facts, history and fiction around the physical sciences. Fun-filled hour for kids aged 6 to 12. Doors open at 2:00 p.m. A free event followed by complimentary refreshments for those in attendance. No reserved seats.