Insects and incest: sib-mating tolerance in natural populations of a parasitoid wasp

International audienc

Histoire des forêts du versant nord des Pyrénées au cours des 30000 dernières années

Les recherches playnologiques réalisées dans le versant nord des Pyrénées ainsi que les données anthracologiques disponibles et les études de macrorestes végétaux permettent de décrire les étapes de la mise en place des principales essences forestières au cours des 30000 dernières années. Dans les Pyrénées centrales, avant 30000 BP, l'épicéa était bien développé. Les données anthracologiques permettent de penser qu'il a disparu des Pyrénées vers 18000-17000 BP. Entre 11000 BP et 10000 BP, l'ultime phase de dégradation climatique de la fin du dernier épisode glaciaire, le Dryas récent, a davantage affecté la couverture végétale des Pyrénées méditerranéennes que celle de la moitié nord occidentale. Au Postglaciaire, le sapin se développe précocement dans la partie orientale de la chaîne et beaucoup plus tard dans la partie occidentale. L'homme agit très tôt sur le milieu montagnard, dès 6200 BP dans les Pyrénées méditerranéennes. Son ection s'accentue particulièrement vers 4000 BP, au Moyen Age, puis au 16è-17è et 18 è siècles lors du développement des forges, déterminant d'importantes modifications phytogéographiques, notamment une extension du hêtre aux dépens du sapin

Radio-Oxidation Ageing of XLPE Containing Different Additives and Filler: Principal Component Analyses of Gases Emission and Consumption

International audienceIn the context of lifetime extension of Nuclear Power Plants (NPPs), electric cable ageing has to be checked to evaluate their performance during normal operation. These electric cables are complex materials, with a conductor and insulating shield in the metal and insulating layer and sheath in the polymer; the most sensitive layer is commonly considered to be the insulating layer. The ageing mechanism upon irradiation under oxidative conditions has been evaluated using gas mass spectrometry and the first conclusions have been drawn. Nonetheless, the data obtained are very numerous and complex; thus, the objective of this new article regards these experimental results using mathematical tools. It allowed confirmation of all the results obtained on these materials, but using chemometrics, i.e., statistical/mathematical analyses, of the results. Using these powerful mathematical tools gives strength to the analyses realised and to the conclusions obtained

Near-Infrared Spectroscopy Analysis of Heavy Fuel Oils Using a New Diffusing Support

International audienc

Development of near infrared sensors: Detection of influential factors by the AComDim method

International audienceThe development of near infrared (NIR) sensors has to go through different steps of testing. Once a prototype is ready to be used, it is necessary to evaluate and optimize the experimental conditions and the data collection, in terms of accuracy, repeatability, reproducibility and speed. This paper studies the effects of controllable experimental factors on the quality of the spectral response, to determine the influence of each instrumental parameter and to improve the predictions obtained from the collected data. The AComDim method, based on the multi-block analysis of ANOVA matrices, was used here to evaluate the impact of experimental factors on the responses from the different sensors tested

Influence of Gamma Irradiation on Electric Cables Models: Study of Additive Effects by Mid-Infrared Spectroscopy

International audienceCables, especially their insulation and jacket materials made of polymers, are vulnerable toageing degradation during normal operation. However, they must remain functional for the entirelife of a nuclear power plant, or even in the event of an accident for cables with a safety requirement.This study focuses on models of crosslinked polyethylene (XLPE)-based insulation of cables anddeals with the structure modification and the behavior of XLPE for nuclear applications due to theeffect of additives. Various additives are added to the polymer formulation to evaluate their impacton ageing. The samples are irradiated at room temperature by several gamma doses, up to 374 kGy,with two dose rates (40 Gy/h and 300 Gy/h) and compared with a non-irradiated sample used asreference. To understand the impact of gamma irradiation on the materials, the principal componentanalysis (PCA) method is applied on spectra recorded through attenuated total reflectance–Fouriertransform infrared (ATR-FTIR) spectroscopy. The results highlight the effects of ageing depending onthe dose rate and on the formulation of the materials, with the identification of different degradationproducts. A curve resolution study compares the effects of different additives on polymer oxidationand shows that the low dose rate leads to a higher degradation than the high dose rate

A FTIR/chemometrics approach to characterize the gamma radiation effects on iodine/epoxy-paint interactions in Nuclear Power Plants

International audienceThe effects of radiation on polymeric materials are a topic of concern in a wide range of industries including the sterilization, and the nuclear power industry. While much work has concentrated on systems like polyolefins that are radiation sterilized, some work has been done on epoxy systems. The epoxy system studied is an epoxy/amine paint which is representative of the paint that covers the inner surfaces of the French nuclear reactor containment buildings. In case of a severe accident on a Nuclear Power Plant, fission products can be released from the nuclear fuel to the reactor containment building. Among them, volatile iodine (I 2) can be produced and can interact with the epoxy-paint. This paint is also subjected to gamma radiation damages (due to the high dose in the containment coming from radio-nuclides released from the fuel). So the epoxy-paint studied was exposed to gamma radiation under air atmosphere after being loaded with I 2 or not. The aim of this study is to characterize by FTIR spectroscopy the iodine-paint interactions, then to identify the radiation damages on the epoxy-paint, and to check their effects on these iodine-paint interactions. This work shows the potential of multi-block analysis method (ANOVA-PCA and COMDIM = AComDim) for such a study as it allows to identify the nature of iodine/epoxy-paint interactions and to characterize the gamma radiation damages on the epoxy-paint. AComDim method conduces to the extraction of Common Components to different tables and highlights factors of influence and their interactions

Simulated aging of lubricant oils by chemometric treatment of infrared spectra: Potential antioxidant properties of sulfur structures

International audienceLubricant oils are complex mixtures of base oils and additives. The evolution of their performance over time strongly depends on its resistance to thermal oxidation. Sulfur compounds revealed interesting antioxidant properties. This study presents a method to evaluate the lubricant oil oxidation. Two samples, a synthetic and a paraffinic base oils, were tested pure and supplemented with seven different sulfur compounds. An aging cell adapted to a Fourier Transform InfraRed (FT-IR) spectrometer allows the continuous and direct analysis of the oxidative aging of base oils. Two approaches were applied to study the oxidation/anti-oxidation phenomena. The first one leads to define a new oxidative spectroscopic index based on a reduced spectral range where the modifications have been noticed (from 3050 to 2750 cm À 1). The second method is based on chemometric treatments of whole spectra (from 4000 to 400 cm À 1) to extract underlying information. A SIMPLe-to-use Interactive Self Modeling Analysis (SIMPLISMA) method has been used to identify more precisely the chemical species produced or degraded during the thermal treatment and to follow their evolution. Pure spectra of different species present in oil were obtained without prior information of their existence. The interest of this tool is to supply relative quantitative information reflecting evolution of the relative abundance of the different products over thermal aging. Results obtained by these two ways have been compared to estimate their concordance

Effect of acclimatization on earthworm's (Eisenia andrei) potential on olive mille wastewaters detoxification

Proceedings of Euro-Mediterranean Conference for Environmental Integration (EMCEI-1), Tunisia 2017International audienceA laboratory vermicomposting (two months duration) was conducted to evaluate the effect of earthworm acclimatization (epigeic—Eisenia andrei) on decomposition and detoxification of olive mill wastewaters. The Earthworm growth rate and phenols reduction were superior in the mixture with acclimated earthworms (21.83 ± 0.01 mg worm−1 day−1 and 72% respectively), than mixture with unacclimated earthworms (4.67 ± 0.01 mg worm−1 day−1 and 41% respectively). The data reveal that acclimatization of earthworms is a promising alternative for OMWW detoxification and vermicomposting (using E. andrei) is a suitable technology for olive by-products conversion into value-added materials