Excited States of Proton-bound DNA/RNA Base Homo-dimers: Pyrimidines

We are presenting the electronic photo fragment spectra of the protonated pyrimidine DNA bases homo-dimers. Only the thymine dimer exhibits a well structured vibrational progression, while protonated monomer shows broad vibrational bands. This shows that proton bonding can block some non radiative processes present in the monomer.Comment: We acknowledge the use of the computing facility cluster GMPCS of the LUMAT federation (FR LUMAT 2764

Segmentation d’Images Texturées Couleur à l’aide de modèles paramétriques pour approche la distribution des erreurs de prédiction linéaires

We propose novel a priori parametric models to approximate the distribution of the two dimensional multichannel linear prediction error in order to improve the performance of color texture segmentation algorithms. Two dimensional linear prediction models are used to characterize the spatial structures in color images. The multivariate linear prediction error of these texture models is approximated with Wishart distribution and multivariate Gaussian mixture models. A novel color texture segmentation framework based on these models and a spatial regularization model of initial class label fields is presented. For the proposed method and with different color spaces, experimental results show better performances in terms of percentage segmentation error, in comparison with the use of a multivariate Gaussian law

Segmentation d’Images Texturées Couleur à l’aide de modèles paramétriques pour approche la distribution des erreurs de prédiction linéaires

International audienceWe propose novel a priori parametric models to approximate the distribution of the two dimensional multichannel linear prediction error in order to improve the performance of color texture segmentation algorithms. Two dimensional linear prediction models are used to characterize the spatial structures in color images. The multivariate linear prediction error of these texture models is approximated with Wishart distribution and multivariate Gaussian mixture models. A novel color texture segmentation framework based on these models and a spatial regularization model of initial class label fields is presented. For the proposed method and with different color spaces, experimental results show better performances in terms of percentage segmentation error, in comparison with the use of a multivariate Gaussian law

A model based framework for land cover classification in high resolution satellite images

International audienc

Set-up and deployment of a high-interaction honeypot: experiment and lessons learned

International audienceThis paper presents the lessons learned from an empirical analysis of attackers behaviours based on the deployment on the Internet of a high-interaction honeypot for more than one year. We focus in particular on the attacks performed via the SSH service and the activities performed by the attackers once they gain access to the system and try to progress in their intrusion. The first part of the paper describes: i) the global architecture of the honeypot and the mechanisms used to capture the implementation details so that we can observe attackers behaviours and ii) the details of the experiment itself (duration, data captured, overview of the attackers activity). The second part presents the results of the observation of the attackers. It includes: i) the description of the global attack process, constituted of two main steps, dictionary attacks and intrusions and ii) the detailed analysis of these two main steps

Development of Ultraviolet-Ultraviolet Hole-Burning Spectroscopy for Cold Gas-Phase Ions

International audienceA new ultraviolet-ultraviolet hole-burning (UV-UV HB) spectroscopic scheme has been developed for cold gas-phase ions in a quadrupole ion trap (QIT) connected with a time-of-flight (TOF) mass spectrometer. In this method, a pump UV laser generates a population hole for the ions trapped in the cold QIT, and a second UV laser (probe) monitors the population hole for the ions extracted to the field-free region of the TOF mass spectrometer. Here, the neutral fragments generated by the UV dissociation of the ions with the second laser are detected. This UV-UV HB spectroscopy was applied to protonated dibenzylamine and to protonated uracil. Protonated uracil exhibits two strong electronic transitions; one has a band origin at 31760 cm-1 and the other at 39000 cm-1. From the UV-UV HB measurement and quantum chemical calculations, the lower-energy transition is assigned to the enol-keto tautomer and the higher-energy one to the enol-enol tautomer

Interstellar and interplanetary solids in the laboratory

International audienceThe composition of the interstellar matter is driven by environmental parameters (e.g. elemental abundance, density, reactant nature, radiations, temperature, time scales) and results also from external interstellar medium physico-chemical conditions. Astrochemists must rely on remote observations to monitor and analyze the com­position of interstellar solids. These observations give essentially access to the molecular functionality of the solids, rarely elemental composition constraints and isotopic fractionation only in the gas phase. Astrochemists bring additional information from the study of analogues produced in the laboratory, placed in simulated space environments. Planetologists and cosmochemists can have access and spectroscopically examine collected extra-terrestrial material directly in the laboratory. Observations of the diffuse interstellar medium (DISM) and molecular clouds (MC) set constraints on the composition of organic solids and large molecules, that! can then be compared with collected extraterrestrial materials analyses, to shed light on their possible links

Interstellar and interplanetary solids in the laboratory

International audienceThe composition of the interstellar matter is driven by environmental parameters (e.g. elemental abundance, density, reactant nature, radiations, temperature, time scales) and results also from external interstellar medium physico-chemical conditions. Astrochemists must rely on remote observations to monitor and analyze the com­position of interstellar solids. These observations give essentially access to the molecular functionality of the solids, rarely elemental composition constraints and isotopic fractionation only in the gas phase. Astrochemists bring additional information from the study of analogues produced in the laboratory, placed in simulated space environments. Planetologists and cosmochemists can have access and spectroscopically examine collected extra-terrestrial material directly in the laboratory. Observations of the diffuse interstellar medium (DISM) and molecular clouds (MC) set constraints on the composition of organic solids and large molecules, that! can then be compared with collected extraterrestrial materials analyses, to shed light on their possible links

Interstellar and interplanetary solids in the laboratory

International audienceThe composition of the interstellar matter is driven by environmental parameters (e.g. elemental abundance, density, reactant nature, radiations, temperature, time scales) and results also from external interstellar medium physico-chemical conditions. Astrochemists must rely on remote observations to monitor and analyze the com­position of interstellar solids. These observations give essentially access to the molecular functionality of the solids, rarely elemental composition constraints and isotopic fractionation only in the gas phase. Astrochemists bring additional information from the study of analogues produced in the laboratory, placed in simulated space environments. Planetologists and cosmochemists can have access and spectroscopically examine collected extra-terrestrial material directly in the laboratory. Observations of the diffuse interstellar medium (DISM) and molecular clouds (MC) set constraints on the composition of organic solids and large molecules, that! can then be compared with collected extraterrestrial materials analyses, to shed light on their possible links