Archive for the Travel Category

off to BayesComp 20, Gainesville

Posted in pictures, Statistics, Travel, University life with tags , , , , , , , , , , , , on January 7, 2020 by xi'an

science under attack [it only gets worse #1074]

Posted in Kids, pictures, Travel, University life with tags , , , , , , , , , , , on January 6, 2020 by xi'an

A chilling overview by the New York Times on the permanent and concerted attacks by the Trump administration on science and the scientific duties of the U.S. Government. [This post was written a week ago, before a much scarier and literal as well as extra-judicial attack took place.]

“Political appointees have shut down government studies, reduced the influence of scientists over regulatory decisions and in some cases pressured researchers not to speak publicly. The administration has particularly challenged scientific findings related to the environment and public health opposed by industries such as oil drilling and coal mining. It has also impeded research around human-caused climate change, which President Trump has dismissed despite a global scientific consensus.”

“The administration’s efforts to cut certain research projects also reflect a longstanding conservative position that some scientific work can be performed cost-effectively by the private sector, and taxpayers shouldn’t be asked to foot the bill.”

“…some of the Trump administration’s moves, like a policy to restrict certain academics from the E.P.A.’s Science Advisory Board or the proposal to limit the types of research that can be considered by environmental regulators, “mark a sharp departure with the past.” Rather than isolated battles between political officials and career experts, these moves are an attempt to legally constrain how federal agencies use science in the first place.”

“In addition to shutting down some programs, there have been notable instances where the administration has challenged established scientific research. Early on, as it started rolling back regulations on industry, administration officials began questioning research findings underpinning those regulations (…) Many top government positions, including at the E.P.A. and the Interior Department, are now occupied by former lobbyists connected to the industries that those agencies oversee.”

Hastings at 50, from a Metropolis

Posted in Kids, pictures, Running, Travel with tags , , , , , , , , , , , , , , , , , , , , , , on January 4, 2020 by xi'an

A weekend trip to the quaint seaside city of Le Touquet Paris-Plage, facing the city of Hastings on the other side of the Channel, 50 miles away (and invisible on the pictures!), during and after a storm that made for a fantastic watch from our beach-side rental, if less for running! The town is far from being a metropolis, actually, but it got its added surname “Paris-Plage” from British investors who wanted to attract their countrymen in the late 1800s. The writers H.G. Wells and P.G. Wodehouse lived there for a while. (Another type of tourist, William the Conqueror, left for Hastings in 1066 from a wee farther south, near Saint-Valéry-sur-Somme.)

And the coincidental on-line publication in Biometrika of a 50 year anniversary paper, The Hastings algorithm at fifty by David Dunson and James Johndrow. More of a celebration than a comprehensive review, with focus on scalable MCMC, gradient based algorithms, Hamiltonian Monte Carlo, nonreversible Markov chains, and interesting forays into approximate Bayes. Which makes for a great read for graduate students and seasoned researchers alike!

Metropolis in 95 characters

Posted in pictures, R, Statistics, Travel with tags , , , , , , , , on January 2, 2020 by xi'an

Here is an R function that produces a Metropolis-Hastings sample for the univariate log-target f when the later is defined outside as another function. And when using a Gaussian random walk with scale one as proposal. (Inspired from a X validated question.)

m<-function(T,y=rnorm(1))ifelse(rep(T>1,T),
  c(y*{f({z<-m(T-1)}[1])-f(y+z[1])<rexp(1)}+z[1],z),y)

The function is definitely not optimal, crashes for values of T larger than 580 (unless one modifies the stack size), and operates the most basic version of a Metropolis-Hastings algorithm. But as a codegolf challenge (on a late plane ride), this was a fun exercise.

start of 2020

Posted in Kids, Mountains, pictures, Travel with tags , , , , , on January 1, 2020 by xi'an

the sky that would not rise [film review]

Posted in Books, Kids, pictures, Travel with tags , , , , , , , , , on December 31, 2019 by xi'an

My 2019 end-of-the-year-movie-with-my-grownup-kids was the final Star Wars episode, Star Wars: The Rise of Skywalker, watched in a quasi-empty theatre with mostly young kids… Surprisingly no one left before the end, which frankly did not come soon enough! The three of us agreed on the appalling conclusion to the trilogy, which recycles about every possible trope from the first series, from the generation antagonism to the endless battle calls and boring space battle scenes (although including an extra that reminded me of the ludicrous first appearance of Radagast the Brown in The Hobbit!), to the compulsory bar scene where some character is faced with some unsavoury past, to a complete disdain for the most basic laws of physics (and swordplay), to humongous snakes that live out of nothing, and cannot produce anything even moderately new in its scenario, recycling an amazing portion of scenes with Carrie Fisher (who died in 2016) as well as involving about every possible former actor. (I am surprised they did not dig Yoda, must have forgotten where the box with his costume was!) The dialogues are incredibly poor and dull, even R2D2’s, there is no meaningful dimension in the relations between the actors, who even more than usual end up focusing on single-minded objectives rather than keeping the larger picture in sight (well-done, General!), and the final scene that relates to the early ones of the 1977 movie with a binary sunset over the Tatooine desert is unbelievably heavy handed. (The picture of R2D2 and C3PO above is taken from a exhibit by Laurent Pons  in Paris, where he included some Star Wars characters in iconic Parisian locations.) May the Force be gone once and for good!

freedom for women jailed in Iran

Posted in Travel, University life with tags , , , , , , , , , , , , , , on December 30, 2019 by xi'an


Three women are currently on hunger strike in Iranian jails to protest against their arbitrary detention under espionage charges and the dire conditions of these detentions. Two of them, Fariba Adelkhah and Nazanin Zaghari-Ratcliffe, are dual nationals with Iranian nationality, whose second nationality is not recognised by Iranian authorities and makes their release from jail the more unlikely. On the French side, Fariba Adelkhah, anthropologist, along with Roland Marchal, sociologist, is a researcher at Sciences Po Paris. They were arrested in June 2019. On the British side, Nazanin Zaghari-Ratcliffe (jailed in April 2016) is working with the Thomson Reuters Foundation, the Canadian news agency Thomson Reuters‘ charitable arm and Kylie Moore-Gilbert (jailed since October 2018) is a  Middle East Lecturer at the University of Melbourne‘s Asia Institute. Petitions have been launched to support them, but I wonder at the possibility to move the Iranian cynical stance other than through the respective governments of these women. (Obviously, there are many many other women and men jailed in Iran for political or other discriminatory reasons who should equally be freed.)