A unique Valanginian paleoenvironment at an iron ore deposit near Zengővárkony (Mecsek Mts, South Hungary), and a possible genetic model

Abstract The spatially restricted Early Valanginian iron ore (limonite) and manganese deposit at Zengõvárkony (Mecsek Mts, southern Hungary) contains a rich, strongly limonitized, remarkably large-sized (specimens are 30–70% larger than those at their type localities) brachiopod-dominated (mainly Lacunosella and Nucleata) megafauna and a diverse crustacean microfauna, which indicates a shallow, nutrient-rich environment possibly linked to an uplifted block, and/or a hydrothermal vent

XPS study of pulsed laser deposited CNx films

International audienceThe C 1s and N 1s core levels of carbon nitrides are composed of several contributions whose assignment is controversial due to the lack of appropriate reference materials and the great variety of configurations of carbon and nitrogen. From the comparison of nitrogen-containing polymeric compounds and solid carbon references an assignment of the individual lines of the C 1s and N 1s core levels is given. Nitrogen-containing polymeric compounds are used as reference materials as they provide a more adequate account of the screening of the ionized states in the photoemission process than molecular references. This screening effect is even more pronounced in case of aromatic or cyanogen-type bonds where delocalized π electrons strongly affect the screening of the core hole. In the second part of the paper these assignments are used to interpret the changes of the chemical environment in pulsed laser deposited carbon nitride films as a result of systematic changes in laser fluence, nitrogen pressure, and target-to-substrate distance. The effect of subsequent annealing and sputtering by argon ions is also discussed. The chemical structure of the films is dominated by nitrile, N(pyramidal)-C(trigonal) and nitrogen in sp2 hybridization (with the electron doublet out of plane) inserted into carbon graphitic network at high laser fluence, and nitrile and pyridinic sp2-hybridized configurations at low laser fluence, in good line with the fact that sp3 and sp2 hybridization states around carbon and nitrile configuration with nitrogen, are preferred

PAC models in stochastic multi-objective multi-armed bandits

Many real-world applications, such as stock markets, energy consumption time series, and scheduling in noisy environments, are characterised by stochastic feedback. In this paper, the evolutionary multi-objective (EMO) techniques, like elitist selection strategies, and the probably approximatively correct (PAC) model are used to analyse the multi-armed bandits (MAB) paradigm that identifies the Pareto front from a finite set of arms with stochastic reward vectors. Each arm is associated with a confidence ball centred in the sampling's mean vector that decreases towards its true vector when the number of samples increases. The Pareto lower upper confidence bound algorithm samples the alternatives for which their confidence ball overlaps with the confidence regions of the Pareto optimal arms. Pareto racing deletes the arms classified with certainty as either suboptimal or Pareto optimal arms. The sample complexity estimates the number of samples required for an accurate approximation of the Pareto front using two different statistics, i.e. empirically determined means or quantiles. The analysed PAC models are empirically compared on realistic datasets with two and three objectives