Archive for the Books Category

humanitarian project in Madagascar

Posted in Books, Kids, pictures, Travel, University life with tags , , , , , , , , , on March 15, 2017 by xi'an

As the budget of the humanitarian trip to Madagascar our daughter organises with other students of the Paris-Sud Medical School next summer is still short of several thousand euros, I repost the call for support I made a few months ago.

Their project is called Mada Tsatsaka, mada for Madagascar and tsatsaka for a local lizard. The team plans to bring basic drugs and educational material and to work in a dispensary, an orphanage, as well as a shelter for women victims of violence. (More below!)

I thus bring this project to the ‘Og’s readers’ attention in case they wish to support. The best approach is use this web site for donations (in English) to Evadeh Mada Tsatsaka. (Evadeh is the mother association for all humanitarian projects in the medical school.) A free-of-charge (!) alternative is to shop on following this associate link as I vouch to transfer all my associate gains in the next four months to the project.

Upon request, more details on the project:

  • 2 weeks in Maventibao working in a clinic : Mada Clinics, helping two nurses with free medical examinations and providing extra medical equipment and drugs. And also helping with drinking water improvement. The team further hopes to help with the purchase of a car associated with the clinic and linking with the hospital in  Diego (4h away) and with hiring a doctor in the nearby clinic of Amboangamamy.
  • 2 weeks in an orphanage in Antananarivo, Ankanifitahiana, in collaboration with BLOC Léo Madagascar, helping in financing and installing a library and a music room, and participating in classes and games with the children. Depending on the funding, the team would also like to help with installing a solar oven.

no publication without confirmation

Posted in Books, Statistics, University life with tags , , , on March 15, 2017 by xi'an

“Our proposal is a new type of paper for animal studies (…) that incorporates an independent, statistically rigorous confirmation of a researcher’s central hypothesis.” (p.409)

A comment tribune in Nature of Feb 23, 2017, suggests running clinical trials in three stages towards meeting higher standards in statistical validation. The idea is to impose a preclinical trial run by an independent team following an initial research showing some potential for some new treatment. The three stages are thus (i) to generate hypotheses; (ii) to test hypotheses; (iii) to test broader application of hypotheses (p.410). While I am skeptical of the chances of this proposal reaching adoption (for various reasons, like, what would the incentive of the second team be [of the B team be?!], especially if the hypothesis is dis-proved, how would both teams share the authorship and presumably patenting rights of the final study?, and how could independence be certain were the B team contracted by the A team?), the statistical arguments put forward in the tribune are rather weak (in my opinion). Repeating experiments with a larger sample size and an hypothesis set a priori rather than cherry-picked is obviously positive, but moving from a p-value boundary of 0.05 to one of 0.01 and to a power of 80% is more a cosmetic than a foundational change. As Andrew and I pointed out in our PNAS discussion of Johnson two years ago.

“the earlier experiments would not need to be held to the same rigid standards.” (p.410)

The article contains a vignette on “the maths of predictive value” that makes intuitive sense but only superficially. First, “the positive predictive value is the probability that a positive result is truly positive” (p.411) A statement that implies a distribution of probability on the space of hypotheses, although I see no Bayesian hint throughout the paper. Second, this (ersatz of a) probability is computed by a ratio of the number of positive results under the hypothesis over the total number of positive results. Which does not make much sense outside a Bayesian framework and even then cannot be assessed experimentally or by simulation without defining a distribution of the output under both hypotheses. Simplistic pictures are the above are not necessarily meaningful. And Nature should certainly invest into a statistical editor!

random forests [reading group]

Posted in Books, Kids, Statistics, University life with tags , , , , , , , on March 14, 2017 by xi'an

Here are the slides I prepared (and recycled) over the weekend for the reading group on machine-learning that recently started in Warwick. Where I am for two consecutive weeks.

a somewhat hasty announcement

Posted in Books, Statistics, University life with tags , , , , , on March 13, 2017 by xi'an

When I received the above RSS newsletter on Thursday, I was a bit shocked as I had not planned to make the existence of the Series B’log known to the entire Society. Even though it was already visible and with unrestricted access. The reason being that experimenting with authors and editors was easier without additional email and password exchanges…

Anyway, now that we have jumped that Rubicon, I would more than welcome comments and suggestions to make the blog structure more efficient and readable. I am still confused as to how the front page should look like, because I want to keep the hierarchy of the Journal, i.e., volume/issue/paper, reflected in this structure, rather than piling up comments and authors’ summaries in an haphazard manner. I have started to tag entries by the volume/issue tag, in order to keep some of this hierarchy respected but I would like to also provide all entries related to a given paper without getting into much extra-work. Given that I already have to process most entries through latex2wp in the best scenario.

Peter Lee (1940?-2017)

Posted in Books, pictures, R, Statistics, University life, Wines with tags , , , , , , on March 12, 2017 by xi'an

Just heard the sad news that Peter Lee, British Bayesian and author of Bayesian Statistics: An Introduction, has passed away yesterday night. While I did not know him, I remember meeting him at a few conferences in the UK and spending an hilarious evening at the pub. When the book came out, I thought it was quite fine an introduction to Bayesian Statistics, with enough mathematical details and prerequisites to make it worthwhile studying, while also including computational recommendations. Fare thee well, Peter.

poverty of medieval students

Posted in Books, Kids, pictures, Travel, University life with tags , , , , on March 11, 2017 by xi'an

enclosure of the "new" court, St John's College, Cambridge, Jan. 27, 2012While waiting for a new staff card in the Human Resources building at the University of Warwick, I browsed through a THE issue and came upon this rather bizarre article by Jack Grove, reporting on a scholarly paper on the tuition and living fees of medieval students, i.e. around the 14th and 15th centuries in Britain, France, or Italy [which did not exist at the time]. Bizarre in that it seemed obvious to me that education in the Middle Ages was severely restricted to a tiny margin of the society…

round-table on Bayes[ian[ism]]

Posted in Books, pictures, Statistics, University life with tags , , , , , , , , , , , , , , on March 7, 2017 by xi'an

In a [sort of] coincidence, shortly after writing my review on Le bayésianisme aujourd’hui, I got invited by the book editor, Isabelle Drouet, to take part in a round-table on Bayesianism in La Sorbonne. Which constituted the first seminar in the monthly series of the séminaire “Probabilités, Décision, Incertitude”. Invitation that I accepted and honoured by taking place in this public debate (if not dispute) on all [or most] things Bayes. Along with Paul Egré (CNRS, Institut Jean Nicod) and Pascal Pernot (CNRS, Laboratoire de chimie physique). And without a neuroscientist, who could not or would not attend.

While nothing earthshaking came out of the seminar, and certainly not from me!, it was interesting to hear of the perspectives of my philosophy+psychology and chemistry colleagues, the former explaining his path from classical to Bayesian testing—while mentioning trying to read the book Statistical rethinking reviewed a few months ago—and the later the difficulty to teach both colleagues and students the need for an assessment of uncertainty in measurements. And alluding to GUM, developed by the Bureau International des Poids et Mesures I visited last year. I tried to present my relativity viewpoints on the [relative] nature of the prior, to avoid the usual morass of debates on the nature and subjectivity of the prior, tried to explain Bayesian posteriors via ABC, mentioned examples from The Theorem that Would not Die, yet untranslated into French, and expressed reserves about the glorious future of Bayesian statistics as we know it. This seminar was fairly enjoyable, with none of the stress induced by the constraints of a radio-show. Just too bad it did not attract a wider audience!