Benchmark of structured machine learning methods for microbial identification from mass-spectrometry data

Microbial identification is a central issue in microbiology, in particular in the fields of infectious diseases diagnosis and industrial quality control. The concept of species is tightly linked to the concept of biological and clinical classification where the proximity between species is generally measured in terms of evolutionary distances and/or clinical phenotypes. Surprisingly, the information provided by this well-known hierarchical structure is rarely used by machine learning-based automatic microbial identification systems. Structured machine learning methods were recently proposed for taking into account the structure embedded in a hierarchy and using it as additional a priori information, and could therefore allow to improve microbial identification systems. We test and compare several state-of-the-art machine learning methods for microbial identification on a new Matrix-Assisted Laser Desorption/Ionization Time-of-Flight mass spectrometry (MALDI-TOF MS) dataset. We include in the benchmark standard and structured methods, that leverage the knowledge of the underlying hierarchical structure in the learning process. Our results show that although some methods perform better than others, structured methods do not consistently perform better than their "flat" counterparts. We postulate that this is partly due to the fact that standard methods already reach a high level of accuracy in this context, and that they mainly confuse species close to each other in the tree, a case where using the known hierarchy is not helpful

Accept'Hydro: a tool for evaluating potential wetland areas at floodplain scale.

National audienceAlluvial wetlands have the functions of hydrological regulation and water purification, but are also of interest for preventing flooding and improving the water quality of the natural environment that serves as a reserve for drinking water and biodiversity. Delimiting these areas is often difficult because it involves both the physical characteristics (topography, river morphology etc.) and hydrodynamic characteristics of the porous medium (permeability etc.) The proposed tool, Accept'Hydro, includes a hydrodynamic simulation of the river, the alluvial aquifer and their interaction, and produces maps of alluvial wetlands with using hydrological criteria. The tool's primary step consists of selecting the studied area using Google Maps, which automatically triggers the generation of a non-uniform mesh covering this area, as well as all the inputs needed for the hydrodynamic simulation to run. The hydrodynamic model based on the equations of Peyrard et al. (2008) allows water levels and flow rates in the river and the alluvial aquifer to be simulated with a non-uniform mesh (cells from 1 to 200 metres per side), combined with a good performance in CPU calculation time. The software program allows the impacts of climate change (changes in hydrology and temperature) and/or anthropogenic change on the hydrodynamic functioning of wetlands to be assessed, and the impact of infrastructure and hydropower facilities on the river to be tested

Simulation du fonctionnement hydrodynamique des milieux humides dans les plaines alluviales

International audienceLa modélisation hydrodynamique est peu utilisée afin de simuler le fonctionnement des milieux humides à l’échelle des plaines alluviales et nécessite souvent de nombreuses données d’entrée souvent difficiles à acquérir. On présente ici un outil de simulation, Accept’Hydro, qui est alimenté par quatre données d’entrée : le modèle numérique d’élévation (IGN), les données piézométriques (banque ADES), l’historique des débits rivières (banque HYDRO), et le réseau hydrographie (BD Carthage). Après l’étape de création automatique du maillage non-uniforme, adapté au domaine étudié, le logiciel génère en sortie les hauteurs d’eau et les vitesses d’écoulement dans la rivière et dans la nappe souterraine, au pas de temps journalier. Les données simulées, sur une période de temps minimal de 10 ans, sont traitées afin de cartographier les milieux humides potentiels en bordure de cours d’eau. De plus, cet outil permet d’intégrer des hypothèses sur l’évolution des débits afin de prendre en compte les modifications dues au change ment climatique, et d’en simuler les impacts sur le fonctionnement hydrologique. On présente ici les résultats d’Accept’Hydro sur la plaine alluviale de la Garonne et ses milieux humides pour la période 2004-2013, dans le département du Tarn-et-Garonne. Dans ce secteur, les simulations prévoient une diminution de la superficie des milieux humides pour l’horizon 2030, en partant d’hypothèses de diminution des débits saisonniers

Comparaison des spectres de basse énergie de 65Cu et 51V

The low energy spectra of Cu65 and V51 are compared with various nuclear models. The spectrum of Cu65 is described by a coupling between the odd proton and the even core, that of V51 by a configuration of the 3 protons outside the closed shells.Les spectres de basse énergie de 65Cu et 51V sont comparés avec divers modèles nucléaires. Le spectre de 65Cu est décrit par un couplage entre le proton impair et le cœur pair, celui de 51V, par une configuration des 3 protons en dehors des couches fermées

Experimental evidences for a finite number of bosons in nuclei at low spin

Experimental data on the /b B/(E2)s between levels with low spin (/b I/<or=11/2) in even-even and odd-/b A/ nuclei are examined, in the framework of algebraic nuclear models, searching for evidences of a finite number of bosons. Positive indications are obtained when comparing even-even and odd-/b A/ nuclei associated in a supermultiplet by a supersymmetry.Anglai

Le Centre de Recherches du Cyclotron de l'U.C.L. à Louvain-la-Neuve : une approche multidisciplinaire de la Recherche fondamentale et de la Recherche appliquée

Vervier Jean. Le Centre de Recherches du Cyclotron de l'U.C.L. à Louvain-la-Neuve : une approche multidisciplinaire de la Recherche fondamentale et de la Recherche appliquée. In: Bulletin de la Classe des sciences, tome 7, n°1-6, 1996. pp. 195-221

Dynamical supersymmetry in /sup 196/Pt and /sup 197/Au

The excitation energies, reduced E2 transition probabilities and spectroscopic factors in the (/sup 3/He,d) reaction for the levels with positive parity in/sup 197/Au up to about 1 MeV, together with the corresponding data for /sup 197/Pt, are shown to be in overall agreement with the prediction of a dynamical supersymmetry scheme recently proposed for nuclei in this mass region.Anglai

Status of the EURISOL project

ELFRISOL is a preliminary design study of the European next-generation isotope separation on line (ISOL) radioactive nuclear beam (RNB) facility, which should extend and amplify, beyond 2010, the exciting work presently carried out with the first-generation ISOL/RNB facilities in Europe and all around the world. The present paper presents a status report, as to 1 May 2002, on the various tasks identified within the project. (C) 2003 Elsevier Science B.V. All rights reserved