Nature snapshots [10 November]

As I was reading Nature in a [noisy] train from Coventry to London, I came across

• India (federal) government scapping nearly 300 science awards this year
• a re-analysis of a sudden infant death conviction in Australia relying on rare genetic mutations rather than statistics (as in Sally Clark’s case)
• a book review about a story of the Huxley family that made me realise I had confused most of them as a single person
• a DNA analysis of Black Death survivors (in both London and Denmark), showing natural selection occurred very quickly during the pandemic and increased the risk of autoimmune diseases
• a genuine design of experiment that demonstrated that light grazing by sheep increases diversity, while fertilization does not
• an astronomy paper on cooling supernovae using Bayes factors
• an attempt at rationalising the answer to the Covid threat involving a large panel of experts (and my colleague Miquel Olui-Barton as a co-author)
• a pessimistic assessment by graduate students of their career prospects

Blackwell-Rosenbluth Award deadline extended to 7 August 2022

The deadline for submission of a nomination for the Blackwell-Rosenbluth j-ISBA Award is now 7 August. Ph.D. students or early career researchers who obtained their PhD after January 1, 2017 are eligible for nomination. A nomination may come from any ISBA member, including the nominee themselves.

important Markov chains

With Charly Andral (PhD, Paris Dauphine), Randal Douc, and Hugo Marival (PhD, Telecom SudParis), we just arXived a paper on importance Markov chains that merges importance sampling and MCMC. An idea already mentioned in Hastings (1970) and even earlier in Fodsick (1963), and later exploited in Liu et al.  (2003) for instance. And somewhat dual of the vanilla Rao-Backwellisation paper Randal and I wrote a (long!) while ago. Given a target π with a dominating measure π⁰≥Mπ, using a Markov kernel to simulate from this dominating measure and subsampling by the importance weight ρ does produce a new Markov chain with the desired target measure as invariant distribution. However, the domination assumption is rather unrealistic and a generic approach can be implemented without it, by defining an extended Markov chain, with the addition of the number N of replicas as the supplementary term… And a transition kernel R(n|x) on N with expectation ρ, which is a minimal(ist) assumption for the validation of the algorithm.. While this initially defines a semi-Markov chain, an extended Markov representation is also feasible, by decreasing N one by one until reaching zero, and this is most helpful in deriving convergence properties for the resulting chain, including a CLT.  While the choice of the kernel R is free, the optimal choice is associated with residual sampling, where only the fractional part of ρ is estimated by a Bernoulli simulation.

BAYSM 2020, Kunming, China [reposted]

The 5th Bayesian Young Statisticians Meeting, BAYSM2020, will take place in Kunming, China (June 26-27, 2020) as a satellite to the ISBA 2020 world meeting. BAYSM is the official conference of j-ISBA, the junior section of the International Society for Bayesian Analysis. It is intended for Ph.D. Students, M.S. Students, Post-Docs, Young and Junior researchers working in the field of Bayesian statistics, providing an opportunity to connect with the Bayesian community at large. Senior discussants will be present at each session, providing participants with hints, suggestions and comments to their work. Distinguished professors of the Bayesian community will also participate as keynote speakers, making an altogether exciting program.

Registration is now open (https://baysm2020.uconn.edu/registration) and will be available with an early bird discount until May 1, 2020. The event will be hosted at the Science Hall of Yunnan University (Kunming, China) right before ISBA 2020 world meeting. BAYSM 2020 will include social events, providing the opportunity to get to know other junior Bayesians.

Young researchers interested in giving a talk or presenting a poster are invited to submit an extended abstract by March 29, 2020. All the instructions for the abstract submission are reported at the page https://baysm2020.uconn.edu/call-dates

Thanks to the generous support of ISBA, a number of travel awards are available to support young researchers.

Keynote speakers:
Maria De Iorio
David Dunson
Sylvia Frühwirth-Schnatter
Xuanlong Nguyen
Amy Shi
Jessica Utts

Confirmed discussants:
Jingheng Cai
Li Ma
Fernando Quintana
Francesco Stingo
Anmin Tang
Yemao Xia

While the meeting is organized for and by junior Bayesians, attendance is open to anyone who may be interested. For more information, please visit the conference website: https://baysm2020.uconn.edu/

postgraduate open day at Warwick [4 Dec]

The department of Statistics at the University of Warwick is holding an open day for prospective PhD students on 4 December 2019, starting at 2pm (with free lunch at 1pm). In the Mathematical Sciences Building common room (room MB1.02). The Director of Graduate Studies, Professor Mark Steel, and the PhD admissions tutors Professors Martyn Plummer and Barbel Finkelstadt Rand will give short presentations about what it means to do a PhD, what it means to do it at Warwick, the benefits of a PhD degree, and the application process.

Subsequently there will be an informal meeting, during which students have the possibility to ask questions and find out more about the different PhD opportunities at Warwick Statistics; in fact, we offer a very broad range of possibilities, giving a lot of choice for potential applicants. Current members of staff will be invited to participate, to discuss potential projects.

UK travel expenses will be covered by the Department of Statistics (standard class travel by public transport with pre-booked tickets). Please register if interested in this event.