Archive for Elsevier
congrats, Dr. Robert!
Posted in Books, Kids, Statistics, University life with tags Department of Internal Medicine, Elsevier, first publication, Fort-de-France, internal medecine, Martinique, Martinique University Hospital, medical thesis, myopathy, publication, residency, Semin Arthritis Rheum, Seminars in Arthritis and Rheumatism on December 25, 2025 by xi'an
Nature tidbits [19 June 2025]
Posted in Books, Kids, pictures, Travel, University life with tags @ScientistTrump, AMOC), Arctic, Atacama, Atlantic Meridional Overturning Circulation, axolotls, ban guns, Chile, China, computer vision, cyborg, defence spending, DOGE, Egypt, Elsevier, Europe, face recognition, First Nations, foreign aid, fossils, France, Greenland, gun control, gun lobby, ice age, infectious diseases, life expectancy, Medicaid, Nature, pangolin, Paris, plastic waste, Pontifical Academy of Science, Science, Svalbard, Thousand Talents Plan, transport accidents, University of Warwick, USA, USAid, Vera Rubin Observatory, WHO, World Health Organization on August 9, 2025 by xi'an
News on the incoming Vera Rubin Observatory telescope in Chile—if not close to the Atacama peaks I climbed during ISBA 2004—and its unique technology (with a camera the size of a car!). As well as a highlight on African space agencies (where I discovered that Egypt is the most active). Plus, a rather vague report on ether0 as a “stepping stone towards a reasoning model“, once again playing with words and double meaning on what’s reason(ing). Further entries (alas!) onH ow Trump 2.0 is reshaping science with the impact of barring entry to 19 countries’ nationals and China multiplying calls to attract researchers from abroad and keep students in the country. Including unusually large salaries and benefits. (Pangolins and axolotls make an appearance in both this issue and the next, how unlikely is this?! With the conflicting items of information that the former are primarily hunted for their scales or for their taste.)
The most frightening section of the 19 June issue is however on the threat of a collapse of the Atlantic Meridional Overturning Circulation (AMOC), which would bring a new Ice Age to Western Europe and dramatic changes in the weather worldwide. Along with several research articles on climate change and its impacts.
tenets of quantile-based inference in Bayesian models
Posted in Books, Statistics with tags ABC, Approximate Bayesian computation, Bayesian inference, Computational Statistics and Data Analysis, cumulative distribution function, density quantile function, Elsevier, g-and-k distributions, insufficient statistic, intractable likelihood, likelihood-free methods, p-pdf, quantile density function, quantile function, Statisfaction on June 8, 2025 by xi'an
This 2023 paper of Perepolkin, Goodrich, and Sahlin vaguely relates to our insufficient Gibbs work in that a Bayesian analysis is conducted based solely on quantile summaries. Except that here the input is the entire cdf, or the—inverse cdf—quantile function, or—its derivative—the quantile density function, instead of the probability density function—used as the likelihood in the posterior. Which is a non-problem from a mathematical perspective since all these functions describe the same probability distribution. Which makes the following quote rather puzzling (in its obviousness).
“We aim to show that the quantile-based Bayesian inference using the intermediate depths leads to the same posterior beliefs as the conventional density-based inference.”
The authors still make a big case of the difference, obviously, to the point of proposing a different notation for Y~F. But using the same symbol f for different densities. The formal expression of the posterior based on the quantile function actually requires the cdf function and the density or the quantile density to be available (at least in a numerical sense), witness eqn (11).
The paper still could hold some interest in its computational component. Relating to ABC, obviously, since distributions defined by quantiles and cdfs often come as benchmarks for ABC, when the associated pdf/likelihood is unavailable. Witness g-and-k distributions (with the caveat MCMC can be implemented in this case). Unfortunately, the paper entirely relies on numerical inversion (with a puzzling comment that MCMC rejection gets higher with numerical inversion, p6). And only mentions ABC in the conclusion, possibly to pacify a referee’s comment. And actually consider that “quantile parameterized quantile distributions don’t lend themselves easily as sampling distributions due to the special nature of their parameterization” (p4). Hence making me wonder at the overall relevance of the entire endeavour….
Nature snapshots [10 Aug 2023]
Posted in Statistics with tags AI regulation, AI scare, Alan Turing, Bletchley Park, chatbots, ChatGPT, China, Elsevier, Hong Kong, mechanics, Nature, tuition fees, UK Government, visa on November 12, 2023 by xi'an
Plenty of AI entries, like Artificial-intelligence search engines wrangle academic literature (as an advanced Google Scholar) and Publishing companies (like Elsevier) developing ChatGPT-like search engines. (While trying to stay clear from fake references!). Plus a long enquiry on Rules to keep AI in check: nations carve different paths for tech regulation about the different approaches envisioned by the EU, the USA, and China, with little practical advance so far for the first two. (While the UK plans its own AI safety summit in Bletchley Park this Fall.)
And an article on how Chinese students are starting to feel less inclined to study abroad. And not only in connection with the COVID pandemic. Or the US growing restrictions on student visas. But mainly because of the quickly growing attractivity of mainland China and Hong Kong universities. (The article states that “For every 1,000 PhDs that have been denied [visa] by the US government, US institutions will lose nearly US$1 billion in tuition fees”, but this does not sound highly relevant since most PhD tuitions are paid from supervisors’ grants, while students from other country may substitute for those denied visa.)
advancements in Bayesian methods and implementations
Posted in Books, Statistics, University life with tags Bayesian Analysis, Bayesian testing, C.R. Rao, Elsevier, Gibbs posterior, Handbook of Advancements in Bayesian Methods and Implementation, manifold exploration, martingales, multiple tests on November 10, 2022 by xi'an
The handbook of (recent) advances in Bayesian methods is now out (at the Elsevierian price of $250!) with chapters on Gibbs posteriors [Ryan Martin & Nicolas Syring], martingale distributions [Walker], selective inference [Daniel García Racines & Alastair Young], manifold simulations [Sumio Watanabe], MCMC for GLMMs [Vivek Roy] and multiple testing [Noirrit Chandra and Sourabh Bhattacharya]. (Along with my chapter on 50 shades of Bayesian testing.) Celebrating 102 years for C.R. Rao, one of the three editors of this volume (as well as the series) along with Arni Srivastava Rao and Alastair Young.
