Martin Lysy

Department of Statistics and Actuarial Science, University of Waterloo

“Comparison and Assessment of Models for Particle Diffusion in Biological Fluids”

Date: Friday, November 7, 2014

Rapidly progressing particle tracking techniques have revealed that foreign particles in biological fluids exhibit rich and at times unexpected behavior, with important consequences for drug delivery. Yet, there remains a frustrating lack of coherence in the description of these particles' motion. Largely this is due to a reliance on functional statistics (e.g., mean-squared displacement) to perform model selection and assess goodness-of-fit. However, not only are these functional characteristics typically estimated with substantial variability, but they are shared by many stochastic processes -- each making fundamentally different predictions for important quantities of scientific interest.

Here, we conduct a detailed Bayesian analysis of leading candidate models for subdiffusive particle trajectories in human pulmonary mucus. Model selection is achieved by way of intrinsic Bayes factors, which avoid both noninformative priors and "using the data twice". Goodness-of-fit is evaluated via several second-order criteria along with exact model residuals. Our findings suggest that a simple model of fractional Brownian motion describes the data just as well as a first-principles physical model of viscoelastic subdiffusion.

Important Dates

December 10 – December 21: Fall Term Exam Period

December 22 – January 2: Winter Holiday (University Closed)

Upcoming Exams

STAT 1000 Final Exam
Tuesday, December 11 at 9:00 a.m.

STAT 2000 Final Exam
Tuesday, December 11 at 1:30 p.m.

STAT 4530 A01 Final Exam
Tuesday, December 11 at 1:30 p.m.

STAT 2150 A01 Final Exam
Tuesday, December 11 at 1:30 p.m.

Upcoming Seminar

Statistics seminar: Erfan Houqe: “Random effects covariance matrix modeling for longitudinal data with covariates measurement error” — Thursday, January 17 at 2:45 p.m., P230 Duff Roblin.

Where are they now?

Stella Leung, M.Sc. (2004)

Shirley Mills, M.Sc. (1970)