Robust specification of the roughness penalty prior distribution in spatially adaptive Bayesian P-splines models

peer reviewedThe potential important role of the prior distribution of the roughness penalty parameter in the resulting smoothness of Bayesian Psplines models is considered. The recommended specification for that distribution yields models that can lack flexibility in specific circumstances. In such instances, these are shown to correspond to a frequentist P-splines model with a predefined and severe roughness penalty parameter, an obviously undesirable feature. It is shown that the specification of a hyperprior distribution for one parameter of that prior distribution provides the desired flexibility. Alternatively, a mixture prior can also be used. An extension of these two models by enabling adaptive penalties is provided. The posterior of all the proposed models can be quickly explored using the convenient Gibbs sampler.IAP research network nr P5/2

Catherine Kerbrat-Orecchioni, Nous et les autres animaux

L’ouvrage de Catherine Kerbrat-Orecchioni, Nous et les autres animaux, paru en 2021 aux éditions Lambert-Lucas spécialisées en sciences du langage, comprend neuf chapitres organisés autour de trois parties. Dans la première partie, intitulée « Regards croisés sur la question animale », l’auteure, professeure à l’Université Lumière Lyon 2 et membre de l’Institut universitaire de France, spécialiste en sciences du langage, décrit le concept de « Césure » qui se dresse entre le monde des hommes ..

Introduction

Introduzione al numero Economie del corpo femminile dal XVI al XXI secolo in America Latina, Europa e Giappone, a cura di Marie-Christine Jullion e Irina Bajini (Università degli Studi di Milano), Mélanie Moreau (Université de Bordeaux-Montaigne)

Gueules cassées : stratégies de séduction anti-gaspillage

Based on a diversified media corpus, the authors have analyzed some of the main linguistic features of the media campaign Gueules cass\ue9es (Ugly Mugs) launched on 16th October 2014 during the World Food Day focused on anti-food waste. In the context of the current crisis, the classic techniques of seduction have to deal with a social responsibility dimension in accordance with the sociopolitical issues of the 21st century.S\u2019appuyant sur un corpus m\ue9diatique diversifi\ue9, les auteurs analysent quelques caract\ue9ristiques linguistiques majeures de la campagne publicitaire \uab Gueules cass\ue9es \ubb lanc\ue9e le 16 octobre 2014 \ue0 l\u2019occasion de la journ\ue9e mondiale de lutte contre le gaspillage alimentaire. Dans le contexte de crise actuel, les techniques classiques de s\ue9duction se chargent d\u2019une dimension de responsabilit\ue9 sociale en accord avec les pr\ue9occupations socio-politiques du d\ue9but du XXIe si\ue8cle

Des collections de minéraux pour quoi faire ?

À travers une approche historique, épistémologique et patrimoniale des minéraux de collection, les auteurs analysent le changement d’image des minéraux et de la façon de les collectionner – notamment leur passage progressif d’objet précieux participant à une représentation idéale de la Nature à spécimens classés et inventoriés, destinés à l’enseignement et à la recherche – et s’interrogent sur l’évolution du statut des collections et les enjeux actuels de leur patrimonialisation

Circulation, retention, and mixing of waters within the Weddell-Scotia Confluence, Southern Ocean:The role of stratified Taylor columns

The waters of the Weddell-Scotia Confluence (WSC) lie above the rugged topography of the South Scotia Ridge in the Southern Ocean. Meridional exchanges across the WSC transfer water and tracers between the Antarctic Circumpolar Current (ACC) to the north and the subpolar Weddell Gyre to the south. Here, we examine the role of topographic interactions in mediating these exchanges, and in modifying the waters transferred. A case study is presented using data from a free-drifting, intermediate-depth float, which circulated anticyclonically over Discovery Bank on the South Scotia Ridge for close to 4 years. Dimensional analysis indicates that the local conditions are conducive to the formation of Taylor columns. Contemporaneous ship-derived transient tracer data enable estimation of the rate of isopycnal mixing associated with this column, with values of O(1000 m2/s) obtained. Although necessarily coarse, this is of the same order as the rate of isopycnal mixing induced by transient mesoscale eddies within the ACC. A picture emerges of the Taylor column acting as a slow, steady blender, retaining the waters in the vicinity of the WSC for lengthy periods during which they can be subject to significant modification. A full regional float data set, bathymetric data, and a Southern Ocean state estimate are used to identify other potential sites for Taylor column formation. We find that they are likely to be sufficiently widespread to exert a significant influence on water mass modification and meridional fluxes across the southern edge of the ACC in this sector of the Southern Ocean

Deep temperature variability in Drake Passage

Observations made on 21 occupations between 1993 and 2016 of GO-SHIP line SR1b in eastern Drake Passage show an average temperature of 0.53°C deeper than 2000 dbar, with no significant trend, but substantial year-to-year variability (standard deviation 0.08°C). Using a neutral density framework to decompose the temperature variability into isopycnal displacement (heave) and isopycnal property change components shows that approximately 95% of the year-to-year variance in deep temperature is due to heave. Changes on isopycnals make a small contribution to year-to-year variability but contribute a significant trend of -1.4±0.6 m°C per year, largest for density (?n)?>?28.1, south of the Polar Front (PF). The heave component is depth-coherent and results from either vertical or horizontal motions of neutral density surfaces, which trend upward and northward around the PF, downward for the densest levels in the southern section, and downward and southward in the Subantarctic Front and Southern Antarctic Circumpolar Current Front (SACCF). A proxy for the locations of the Antarctic Circumpolar Current (ACC) fronts is constructed from the repeat hydrographic data and has a strong relationship with deep ocean heat content, explaining 76% of deep temperature variance. The same frontal position proxy based on satellite altimeter-derived surface velocities explains 73% of deep temperature variance. The position of the PF plays the strongest role in this relationship between ACC fronts and deep temperature variability in Drake Passage, although much of the temperature variability in the southern half of the section can be explained by the position of the SACCF. This article is protected by copyright. All rights reserved

The thermodynamic balance of the Weddell Gyre

The thermodynamic balance of the Weddell Gyre is assessed from an inverse estimate of the circulation across the gyre's rim. The gyre experiences a weak net buoyancy gain that arises from a leading-order cancellation between two opposing contributions, linked to two cells of water mass transformation and diapycnal overturning. The lower cell involves a cooling-driven densification of 8.4 ± 2.0 Sv of Circumpolar Deep Water and Antarctic Bottom Water near the gyre's southern and western margins. The upper cell entails a freshening-driven conversion of 4.9 ± 2.0 Sv of Circumpolar Deep Water into lighter upper-ocean waters within the gyre interior. The distinct role of salinity between the two cells stems from opposing salinity changes induced by sea ice production, meteoric sources and admixture of fresh upper-ocean waters in the lower cell, which contrasts with coherent reductions in salinity associated with sea ice melting and meteoric sources in the upper cell