Leon Glass

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Leon Glass
Born (1943-03-29) March 29, 1943 (age 81)
Alma mater Brooklyn College
University of Chicago
Awards Guggenheim Fellowship (1994)
Royal Society of Canada Fellow (1998)
American Physical Society Fellow (1999)
Society for Industrial and Applied Mathematics Fellow (2009)
Scientific career
Institutions University of Edinburgh
University of Chicago
University of Rochester
McGill University
Doctoral advisor Stuart Rice

Leon Glass (born 1943) is an American scientist who has studied various aspects of the application of mathematical and physical methods to biology, with special interest in vision, cardiac arrhythmia, and genetic networks.

Contents

Biography

Leon Glass was born in Brooklyn, NY where he attended Erasmus Hall High School (Class of 1959) and majored in Chemistry at Brooklyn College (Class of 1963). [1] He obtained a Ph.D. in Chemistry in 1968 from the University of Chicago studying theory of atomic motions in simple liquids. [2] Glass was a postdoctoral fellow in machine intelligence and perception (University of Edinburgh), theoretical biology (University of Chicago), and physics and astronomy (University of Rochester). [3]

In 1975, Glass joined the department of physiology at McGill University, where he is professor emeritus [4] and the Isadore Rosenfeld chair in Cardiology. [5] He was awarded a Guggenheim Fellowship in 1994 [6] and is a Fellow of the Royal Society of Canada (1998), [7] the American Physical Society (1999), [8] and the Society for Industrial and Applied Mathematics (2009). [9] Leon Glass is a father of two and lives in Montreal, Canada. [1]

Glass is also a French horn player, and is part of the executive committee of the I Medici di McGill Orchestra, an orchestra consisting mainly of McGill University's medical students and professors. [10]

Work

Glass' early work and eponymous patterns were fostered by mentor Christopher Longuet-Higgins, who guided him in the application of statistical methods to visual perception. [11] Glass patterns are formed from superimposed random dot patterns: an original image with a second image which has been generated through a linear or nonlinear transformation of the original. [12] A variety of different spatial patterns such as circles, spirals, hyperbolae, can be perceived in the superimposed image set, depending on the nature of the transformation between the two sets of dots. This discovery provided insight into mathematical nature of human perception by suggesting that the visual cortex is capable of computing a large number of autocorrelations in parallel. [12]

David Marr first coined the term "Glass patterns" in his 1982 work on visual perception, [13] resulting in an increased interest in the phenomenon. Because of their mathematical simplicity and physiological underpinnings, Glass patterns have subsequently been used in dozens of electrophysiology and visual psychophysics experiments, resulting in additional understanding of the physiology of visual perception. [11]

Glass may be best known for his work with colleagues at McGill University, suggesting that certain physiological disorders may be considered dynamical diseases. These are characterized by sudden changes in the qualitative dynamics of a physiological control mechanism, which leads to disease. These features are illustrated in the Mackey-Glass equations. [14] [15] According to James Gleick, who recounted conversations with Glass in his book Chaos: Making a New Science, foundational work in chaos by the McGill group was performed using animal models. [16] He quotes Glass saying: "Many different rhythms can be established between a stimulus and a little piece of chicken heart". [16] Since the initial description of dynamical diseases, a large number of researchers have analyzed mathematical models of physiological systems. Examples of dynamical diseases have been described in medical fields as diverse as hematology, cardiology, neurology, and psychiatry. [17] [18] Dynamical disease modeling has been used to understand cardiac arrhythmia, and specific model detection algorithms are now being programmed into pacemakers so that pathological patterns can be detected and corrected. [19]

Publications

Books

Selected articles

Related Research Articles

<span class="mw-page-title-main">Chaos theory</span> Field of mathematics and science based on non-linear systems and initial conditions

Chaos theory is an interdisciplinary area of scientific study and branch of mathematics. It focuses on underlying patterns and deterministic laws of dynamical systems that are highly sensitive to initial conditions. These were once thought to have completely random states of disorder and irregularities. Chaos theory states that within the apparent randomness of chaotic complex systems, there are underlying patterns, interconnection, constant feedback loops, repetition, self-similarity, fractals and self-organization. The butterfly effect, an underlying principle of chaos, describes how a small change in one state of a deterministic nonlinear system can result in large differences in a later state. A metaphor for this behavior is that a butterfly flapping its wings in Brazil can cause a tornado in Texas.

<span class="mw-page-title-main">Fractal</span> Infinitely detailed mathematical structure

In mathematics, a fractal is a geometric shape containing detailed structure at arbitrarily small scales, usually having a fractal dimension strictly exceeding the topological dimension. Many fractals appear similar at various scales, as illustrated in successive magnifications of the Mandelbrot set. This exhibition of similar patterns at increasingly smaller scales is called self-similarity, also known as expanding symmetry or unfolding symmetry; if this replication is exactly the same at every scale, as in the Menger sponge, the shape is called affine self-similar. Fractal geometry lies within the mathematical branch of measure theory.

<span class="mw-page-title-main">Weber–Fechner law</span> Related laws in the field of psychophysics

The Weber–Fechner laws are two related scientific laws in the field of psychophysics, known as Weber's law and Fechner's law. Both relate to human perception, more specifically the relation between the actual change in a physical stimulus and the perceived change. This includes stimuli to all senses: vision, hearing, taste, touch, and smell.

<span class="mw-page-title-main">Limit cycle</span> Behavior in a nonlinear system

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<span class="mw-page-title-main">David H. Hubel</span> Canadian neurophysiologist

David Hunter Hubel was an American Canadian neurophysiologist noted for his studies of the structure and function of the visual cortex. He was co-recipient with Torsten Wiesel of the 1981 Nobel Prize in Physiology or Medicine, for their discoveries concerning information processing in the visual system. For much of his career, Hubel worked as the Professor of Neurobiology at Johns Hopkins University and Harvard Medical School. In 1978, Hubel and Wiesel were awarded the Louisa Gross Horwitz Prize from Columbia University. In 1983, Hubel received the Golden Plate Award of the American Academy of Achievement.

<span class="mw-page-title-main">Heart rate variability</span> Variation in the time intervals between heartbeats

Heart rate variability (HRV) is the physiological phenomenon of variation in the time interval between heartbeats. It is measured by the variation in the beat-to-beat interval.

<span class="mw-page-title-main">Neural oscillation</span> Brainwaves, repetitive patterns of neural activity in the central nervous system

Neural oscillations, or brainwaves, are rhythmic or repetitive patterns of neural activity in the central nervous system. Neural tissue can generate oscillatory activity in many ways, driven either by mechanisms within individual neurons or by interactions between neurons. In individual neurons, oscillations can appear either as oscillations in membrane potential or as rhythmic patterns of action potentials, which then produce oscillatory activation of post-synaptic neurons. At the level of neural ensembles, synchronized activity of large numbers of neurons can give rise to macroscopic oscillations, which can be observed in an electroencephalogram. Oscillatory activity in groups of neurons generally arises from feedback connections between the neurons that result in the synchronization of their firing patterns. The interaction between neurons can give rise to oscillations at a different frequency than the firing frequency of individual neurons. A well-known example of macroscopic neural oscillations is alpha activity.

<span class="mw-page-title-main">Denis Noble</span> British biologist (born 1936)

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Vagal tone is activity of the vagus nerve, the 10th cranial nerve and a fundamental component of the parasympathetic branch of the autonomic nervous system. This branch of the nervous system is not under conscious control and is largely responsible for the regulation of several body compartments at rest. Vagal activity results in various effects, including: heart rate reduction, vasodilation/constriction of vessels, glandular activity in the heart, lungs, and digestive tract, liver, immune system regulation as well as control of gastrointestinal sensitivity, motility and inflammation.

<span class="mw-page-title-main">Ankyrin-2</span> Protein-coding gene in the species Homo sapiens

Ankyrin-2, also known as Ankyrin-B, and Brain ankyrin, is a protein which in humans is encoded by the ANK2 gene. Ankyrin-2 is ubiquitously expressed, but shows high expression in cardiac muscle. Ankyrin-2 plays an essential role in the localization and membrane stabilization of ion transporters and ion channels in cardiomyocytes, as well as in costamere structures. Mutations in ANK2 cause a dominantly-inherited, cardiac arrhythmia syndrome known as long QT syndrome 4 as well as sick sinus syndrome; mutations have also been associated to a lesser degree with hypertrophic cardiomyopathy. Alterations in ankyrin-2 expression levels are observed in human heart failure.

Ralph Mitchell Siegel, a researcher who studied the neurological underpinnings of vision, was a professor of neuroscience at Rutgers University, Newark, in the Center for Molecular and Behavioral Neuroscience. He died September 2, 2011, at his home following a long illness.

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George Edward Billman is an American physiologist and professor at Ohio State University. After receiving a Ph.D from the University of Kentucky in 1980, Billman began his professional career at the University of Oklahoma. In 1984, he joined the Ohio State staff, where he became an associate professor in 1990 and a full professor in 1996.

<span class="mw-page-title-main">David A. Eisner</span>

David Alfred Eisner, FRCP (Hon), FMedSci, is British Heart Foundation Professor of Cardiac Physiology at the University of Manchester and editor-in-chief of The Journal of General Physiology (JGP).

Rahul Pandit is an Indian condensed matter physicist, a professor of physics and a divisional chair at the Indian Institute of Science. Known for his research on phase transitions and spatiotemporal chaos and turbulence, Pandit is an elected fellow of the Indian Academy of Sciences, Indian National Science Academy and The World Academy of Sciences. The Council of Scientific and Industrial Research, the apex agency of the Government of India for scientific research, awarded him the Shanti Swarup Bhatnagar Prize for Science and Technology, one of the highest Indian science awards, for his contributions to physical sciences in 2001.

Michael C. Mackey is a Canadian-American biomathematician and Professor in the Department of Physiology of McGill University in Montreal, Quebec, Canada who holds the Joseph Morley Drake Emeritus Chair.

In mathematics and mathematical biology, the Mackey–Glass equations, named after Michael Mackey and Leon Glass, refer to a family of delay differential equations whose behaviour manages to mimic both healthy and pathological behaviour in certain biological contexts, controlled by the equation's parameters. Originally, they were used to model the variation in the relative quantity of mature cells in the blood. The equations are defined as:

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References

  1. 1 2 "Leon Glass Curriculum Vitae" (PDF). Retrieved March 25, 2013.
  2. Glass, Leon (1968). Theory of atomic motions in simple liquids (Thesis). University of Chicago. OCLC   49445341.
  3. "My Career in Mathematical Biology: A Personal Journey" (PDF). Retrieved March 25, 2013.
  4. "Leon Glass - Emeritus Professor". Department of Physiology. Retrieved April 26, 2023.
  5. "Named/Endowed Chair Appointments at McGill University". Archived from the original on March 28, 2013. Retrieved March 25, 2013.
  6. "Fellows: John Simon Guggenheim Memorial Foundation". Archived from the original on January 14, 2013. Retrieved March 27, 2013.
  7. "Fellows, The Royal Society of Canada". Archived from the original on February 4, 2020. Retrieved March 25, 2013.
  8. "Archive (1990-Present), Fellows of the American Physical Society" . Retrieved March 25, 2013.
  9. "SIAM Fellows: Class of 2009" . Retrieved March 25, 2013.
  10. "Executive Committee 2015 -". I Medici di McGill Orchestra. Retrieved October 2, 2016.
  11. 1 2 Glass, Leon; Smith, Matthew A. (2011). "Glass Patterns". Scholarpedia. 6 (8): 9594. Bibcode:2011SchpJ...6.9594G. doi: 10.4249/scholarpedia.9594 .
  12. 1 2 Glass, Leon (1969). "Moire effect from random dots". Nature . 223 (5206): 578–580. Bibcode:1969Natur.223..578G. doi:10.1038/223578a0. PMID   5799528. S2CID   4267348.
  13. Marr, David (1982). Vision: A Computational Investigation into the Human Representation and Processing of Visual Information . Freeman.
  14. Mackey, Michael C.; Glass, Leon (1977). "Oscillation and chaos in physiological control systems". Science . 197 (4300): 287–289. Bibcode:1977Sci...197..287M. doi:10.1126/science.267326. hdl: 10338.dmlcz/127762 . PMID   267326.
  15. Glass, Leon; Mackey, Michael C. (1979). "Pathological conditions resulting from instabilities in physiological control systems". Annals of the New York Academy of Sciences. 316 (1): 214–235. Bibcode:1979NYASA.316..214G. doi:10.1111/j.1749-6632.1979.tb29471.x. PMID   288317. S2CID   20356081.
  16. 1 2 Gleick, James (1987). Chaos: Making a New Science. Vintage Books. ISBN   978-0-7493-8606-1.
  17. Belair, Jacques; Glass, Leon; an der Heiden, Uwe; Milton, John (1995). "Dynamical Disease: Identification, Temporal Aspects and Treatment Strategies for Human Illness". Chaos: An Interdisciplinary Journal of Nonlinear Science. 5 (1): 1–7. Bibcode:1995Chaos...5....1B. doi:10.1063/1.166069. PMID   12780147.
  18. Milton, John; Jung, Peter (2003). Epilepsy as a Dynamic Disease. Springer. ISBN   978-3-540-42762-9.
  19. USpatent 7146206,Glass, Leon; Tateno, Katsumi,"Detection of cardiac arrhythmia using mathematical representation of standard .DELTA.RR probability density histograms",published 2006-12-05, assigned to Medtronic