Partition games

We introduce CUT, the class of 2-player partition games. These are NIM type games, played on a finite number of heaps of beans. The rules are given by a set of positive integers, which specifies the number of allowed splits a player can perform on a single heap. In normal play, the player with the last move wins, and the famous Sprague-Grundy theory provides a solution. We prove that several rulesets have a periodic or an arithmetic periodic Sprague-Grundy sequence (i.e. they can be partitioned into a finite number of arithmetic progressions of the same common difference). This is achieved directly for some infinite classes of games, and moreover we develop a computational testing condition, demonstrated to solve a variety of additional games. Similar results have previously appeared for various classes of games of take-and-break, for example octal and hexadecimal; see e.g. Winning Ways by Berlekamp, Conway and Guy (1982). In this context, our contribution consists of a systematic study of the subclass `break-without-take'

Modeling the wind circulation around mills with a Lagrangian stochastic approach

This work aims at introducing model methodology and numerical studies related to a Lagrangian stochastic approach applied to the computation of the wind circulation around mills. We adapt the Lagrangian stochastic downscaling method that we have introduced in [3] and [4] to the atmospheric boundary layer and we introduce here a Lagrangian version of the actuator disc methods to take account of the mills. We present our numerical method and numerical experiments in the case of non rotating and rotating actuator disc models. We also present some features of our numerical method, in particular the computation of the probability distribution of the wind in the wake zone, as a byproduct of the fluid particle model and the associated PDF method

Personnage secondaire ou second héros : la place paradoxale de Sam dans Le Seigneur des Anneaux

Subordonné à Frodo par le schéma actantiel du Seigneur des Anneaux et par son statut social qui le rattache à un autre registre ou genre littéraire, Sam peut aussi être vu comme l’image d’un serviteur de la Première Guerre mondiale, tendrement fidèle à son officier. Une importance particulière sera donnée au chapitre final du livre IV, dans lequel Sam pourrait devenir le héros du roman, mais le refuse. Cet épisode manifeste qu’il est un personnage secondaire parce qu’il a conscience d’être dans un récit ; parce qu’il en est, en puissance, déjà un narrateur.Sam is subordinate to Frodo because of the actantial model of the Lord of the Rings and of his social status, which makes him related to another register or literary genre. Sam may also be seen as similar to a First World War “batman”, tenderly faithful to his officer. Close attention will be paid to the final chapter of book IV, in which Sam could become the hero of the novel, but refuses to do so. This episode shows Sam as a sidekick because he is aware of being in a story; because potentially he is already its narrator

Le texte, le terrarium et le gaffophone

Nous souhaitons proposer dans cet article une réflexion sur l\u27écriture des articles scientifiques, en défendant l\u27idée que les textes rendant compte de recherches doivent être considérés comme des textes à part entière, c\u27est-à-dire comme des environnements ayant leur propre cohérence, qui échappe en partie à leurs auteurs. En partant de cette hypothèse, nous adoptons pour notre propre article une forme qui donne une large part aux jeux d\u27échos entre des citations, issues de textes volontairement très différents

Output-Weighted Sampling for Multi-Armed Bandits with Extreme Payoffs

We present a new type of acquisition functions for online decision making in multi-armed and contextual bandit problems with extreme payoffs. Specifically, we model the payoff function as a Gaussian process and formulate a novel type of upper confidence bound (UCB) acquisition function that guides exploration towards the bandits that are deemed most relevant according to the variability of the observed rewards. This is achieved by computing a tractable likelihood ratio that quantifies the importance of the output relative to the inputs and essentially acts as an \textit{attention mechanism} that promotes exploration of extreme rewards. We demonstrate the benefits of the proposed methodology across several synthetic benchmarks, as well as a realistic example involving noisy sensor network data. Finally, we provide a JAX library for efficient bandit optimization using Gaussian processes.Comment: 10 pages, 4 figures, 1 tabl

CBCT princípio de funcionamento, interesse e limitação na prática de medicina dentária

Dissertação para obtenção do grau de Mestre no Instituto Universitário Egas MonizDepois de abordada a história da CBCT, descrevemos rapidamente o seu modo de funcionamento. Analisamos as vantagens e as desvantagens desta tecnologia nova na prática da medicina dentária. Para terminar, são revistas as aplicações da imagiologia a 3D na medicina dentária em função das várias especializações. São também abordados os progressos das técnicas associadas ao funcionamento desta máquina e o seu impacto na sociedade

53BP1 Repair Kinetics for Prediction of In Vivo Radiation Susceptibility in 15 Mouse Strains

International audienceWe present a novel mathematical formalism to predict the kinetics of DNA damage repair after exposure to both low- and high-LET radiation (X rays; 350 MeV/n 40Ar; 600 MeV/n 56Fe). Our method is based on monitoring DNA damage repair protein 53BP1 that forms radiation-induced foci (RIF) at locations of DNA double-strand breaks (DSB) in the nucleus and comparing its expression in primary skin fibroblasts isolated from 15 mice strains. We previously reported strong evidence for clustering of nearby DSB into single repair units as opposed to the classic “contact-first” model where DSB are considered immobile. Here we apply this clustering model to evaluate the number of remaining RIF over time. We also show that the newly introduced kinetic metrics can be used as surrogate biomarkers for in vivo radiation toxicity, with potential applications in radiotherapy and human space exploration. In particular, we observed an association between the characteristic time constant of RIF repair measured in vitro and survival levels of immune cells collected from irradiated mice. Moreover, the speed of DNA damage repair correlated not only with radiation-induced cellular survival in vivo, but also with spontaneous cancer incidence data collected from the Mouse Tumor Biology database, suggesting a relationship between the efficiency of DSB repair after irradiation and cancer risk