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This Week’s Discoveries | 7 February 2017

7 February 2017
Oort Building
Niels Bohrweg 2
2333 CA Leiden
De Sitterzaal

First Lecture


The horseshoe prior for sparse problems


Stéphanie van der Pas (MI) is a PhD student in the Statistical Science group, supervisor Aad van der Vaart, at MI. Her research interests are: sparsity, Bayesian nonparametrics, community detection, survival analysis. She will defend her PhD thesis on February 28.

The rise of big data sets with few signals, such as gene expression data and astronomical images, has given an impulse to the study of sparse models. I will discuss some recent results on the horseshoe prior, a Bayesian method for estimation, uncertainty quantification and model selection designed for sparse problems.

Second Lecture

Large-scale Research Facilities

Ewine van Dishoeck ( Leiden Observatory  helped develop the most powerful telescopes in the world. She conducts research into thin, ice-cold clouds of gas that are found between the stars close to our own solar system, including in the Orion Nebula, of which the Hubble telescope has made such breath-taking images. She is chair of the Committee Large-scale Research of the KNAW who presented the Agenda for Large-scale Research Facilities in October 2016.

Large-scale research facilities are important for scientific progress in many disciplines. The necessary investment requires scientists to take the long view, make unambiguous choices, and plan carefully.

What counts as a large-scale research facility naturally differs from one discipline to the other. They may be large telescopes or measuring equipment but can also be facilities for accessing archives and collections. What these facilities have in common is that they are so expensive or complex that no single university (or sometimes even a single country) can fund or operate them on its own, making national, European or even global cooperation a necessity.

This brief presentation will summarize the activities of the KNAW to inspire scientists to 'dream' about the next generation of large-scale research facilities, as well as the new Roadmap put together by NWO for financing large facilities in the coming years. Both the KNAW Agenda and NWO Roadmap contain facilities in which various institutes of the Leiden Faculty of Science are actively involved.