Paul Kirk — Bayesian Inference for tumor heterogeneity using the Hamming Ball Sampler
Starts: 2:00 pm
Ends: October 23, 2014 - 3:00 pm
Location: GBSF auditorium
Description: Presenter: Paul Kirk, Department of Statistics and Wellcome Trust Centre for Human Genetics, University of Oxford, UK
Abstract: The characterization of sub-clonal structure from whole genome sequencing of heterogeneous tumors is a computationally challenging problem due to the large number of mutations and unknown number of tumor sub-populations. Many recent approaches have adopted methods based on Bayesian nonparametric models (the Dirichlet or Indian Buffet Process) but standard computational methods for inference for these models can be slow as they rely on inefficient Markov Chain Monte Carlo methods. We have developed a novel Markov Chain Monte Carlo sampling algorithm that allows efficient and exact Bayesian inference for multiple membership models that is scalable to massive datasets. While standard approaches use asymmetric updates that are prone to becoming trapped in local modes, our algorithm uses locally symmetric modes that allows joint updating of the latent variable structure. We illustrate the utility of the sampling algorithm for tumor deconvolution problems and demonstrate its advantage over standard computational alternatives.
For questions, or to meet with the speaker, please contact Luis Carvajal-Carmona (firstname.lastname@example.org) or John Williamson (email@example.com)
Diana Wall — Lessons from an Antarctic Desert Documenting Climate Change and Measuring its Impact on Soil Life
Starts: 4:10 pm
Ends: October 23, 2014 - 5:10 pm
Location: 3 Kleiber Hall
Description: Diana Wall:
University Distinguished Professor, Department of Biology Director, School of Global Environmental Sustainability Colorado State University
Dr. Wall is an internationally recognized ecologist for her research to explore how soil biodiversity contributes to healthy, productive soils and thus benefits society, and the consequences of human activities on soil sustainability. Her global research includes more than twenty years of research in the Antarctic Dry Valleys examining how climate change affects soil biodiversity, ecosystem processes and ecosystem services. Wall Valley, Antarctica was named for her achievements in 2005.
She serves as Science Chair for the Global Soil Biodiversity Initiative. A Board Member of the World Resources Institute, she has served also as President of the Ecological Society of America, the American Institute of Biological Sciences, the Association of Ecosystem Research Centers, the Society of Nemaologists, and Chair of the Council of Scientific Society Presidents. She is a Fellow of the American Association for the Advancement of Science, is a member of the American Academy of Arts and Science, and holds an Honorary Doctorate from Utrecht University, The Netherlands. Dr. Wall received the 2013 Tyler Prize for Environmental Achievement, which is the premier international award for environmental science, environmental health and energy conferring great benefit upon mankind.