• home
• future students
• graduate
• events
• pims lectures

The Provost's Distinguished Women Scholar Lecture is supported by the Provost’s Distinguished Women Scholars Lecture Committee and the Pacific Institute for the Mathematical Sciences.

• Tea reception 6:00-6:30pm
• Public talk 6:30-9:00pm

Abstract

New kinds of data are giving rise to exciting new opportunities in public health. The recent revolution in DNA sequencing means that for the first time, we can read the sequences of viruses and bacteria that cause human disease. This allows us to track their evolution through time, and even to track how they are spreading through communities and environments. However, the best ways to control infectious disease do not leap off the pages of these data. Instead, we need to build ways to model and understand these rich sources of data, and we need to connect the information we gain to our efforts in public health. These tasks require new mathematics. In my group, we have developed a way to connect the DNA sequences from bacterial infections to 'outbreak stories' -- who infected whom and when. We combine genomic data, locations and clinical histories, allowing us to estimate how the infection spreads in a community. I will describe how the method works and some of its applications for public health, and I will give a broader picture of some of the coming challenges that healthcare brings to the mathematical sciences.

The Provost's Distinguished Women Scholar Lecture is supported by the Provost’s Distinguished Women Scholars Lecture Committee and the Pacific Institute for the Mathematical Sciences.

• Tea reception 3:00-3:20pm
• Academic Seminar 3:20-4:20pm

Abstract

Improvements in sequencing technology mean that we have rich data on how infections evolve and spread. In this talk I will describe two settings where this calls for new mathematics. Trees -- in the sense of graphs with no cycles -- are a cornerstone of how we understand these data. Trees can represent patterns of ancestry through time, showing evolutionary stories that are supported by data and revealing how consistent models are with data. In the first part of the talk, I will describe a metric on trees that is based on polynomial representations of trees. Since each tree has a unique polynomial, comparing the coefficients yields a suite of tree comparison tools. We illustrate these with data from cetacean evolution and infectious disease. In the second part of the talk, I will describe how we can use trees, together with a type of colouring, to do Bayesian inference of who infected whom in an infectious disease outbreak. I will apply this tool to data from tuberculosis infections.

PIMS Distinguished Lecture

Join us for refreshments at a meet and greet at 3:00 pm, the talk will follow at 3:30 pm.

ABSTRACT: Optimization and optimal dynamical control are used to investigate the accuracy of analytical estimates for solutions of some basic nonlinear partial differential equations of mathematical hydrodynamics. Even though many mathematical estimates are demonstrably sharp, the result of a sequence of applications of such estimates need not be, leaving uncertainty in the precision of the ultimate result of the analysis. We examine the classical analysis bounding enstrophy and palinstrophy amplification in Burgers’ and the Navier-Stokes equations and discover that the best known instantaneous growth rates estimates for these quantities are indeed sharp. Integrating the estimates in time may (as in the 2D Navier-Stokes case) but does not always (as in the Burgers case) produce sharp estimates in which case optimal control techniques must be brought to bear to determine the actual extreme behavior of the nonlinear dynamics. The question for the 3D Navier-Stokes equations remains unresolved although work is in progress to apply these tools to address it. The most recent work reported here is joint with Diego Ayala and Thilo Simon, Journal of Fluid Mechanics 837, 839–857 (2018).

Download poster (PDF)

Prof. Gerta Keller’s major research and discoveries ranged from climate change and its effects on ocean circulation, ocean anoxic events, polar warming, Deccan volcanism, comet showers, extraterrestrial impacts, the dinosaur mass extinction, the age of the Chicxulub impact and the 6th mass extinction. Her research frequently challenged accepted scientific dogma and placed her at the center of acrimonious debates fighting for survival of truth-based evidence. All but the cause of the Chicxulub impact were soon accepted by scientists and integrated into new research. After four decades, impact proponents still fiercely defend the impact theory, deny contrary evidence and at best incorporate volcanism as ad hoc revisions, proclaiming the impact triggered volcanism that caused the mass extinction.

Abstract: For the past 40 years the demise of the dinosaurs has been attributed to an asteroid impact on Yucatan, a theory that is imaginative, popular and even sexy. From the very beginning, scientists who doubted this theory were threatened into silence or their careers destroyed by the main theory proponents. Thus began the Dinosaur wars in 1980 – and still continuing. As in any war, there are two sides to the Dinosaur wars. The majority believes an asteroid hit Yucatan and instantaneously wiped out 75% of all life including the dinosaurs in a global firestorm and nuclear type winter. A small minority tested this theory and found contrary evidence that supported Deccan volcanism in India that caused rapid climate warming due to greenhouse gases (CO2), environmental stress, acid rain and ocean acidification culminating in the mass extinctions. This lecture highlights the four decades of the dinosaur wars, the increasing acceptance of volcanism’s catastrophic effects and likely cause of the mass extinction and the resulting ad hoc revisions to accommodate the impact theory.

Download poster (PDF)

The subject of mathematical ecology is one of the oldest and most exciting in mathematical biology, and has helped in the management of natural systems and infectious diseases. Though many problems remain in those areas, we face new challenges today in finding ways to cooperate in managing our Global Commons. From behavioral and evolutionary perspectives, our societies display conflict of purpose or fitness across levels, leading to game-theoretic problems in understanding how cooperation emerges in Nature, and how it might be realized in dealing with problems of the Global Commons. This lecture will attempt to weave these topics together, tracing the evolution from earlier work to challenges for the future.