Zirconium oxidation under high energy heavy ion irradiation

This paper concerns the study of zirconium oxidation under irradiation with high energetic Xe ions. The irradiations were performed on the IRRSUD beam line at GANIL (Caen). The oxygen partial pressure was fixed at 10$^{-3}$ Pa and two temperature conditions were used, either 480$\circ$C reached by Joule effect heating or 280$\circ$C due to Xe energy deposition. Zirconia was fully characterized by Rutherford Backscattering Spectrometry, Transmission Electron Microscopy and Grazing Angle X-ray Diffraction. Apparent diffusion coefficients of oxygen in ZrO2 were determined from these experiments by using a model which takes into account a surface exchange between oxygen gas and the ZrO2 surface. These results are compared with thermal oxidation data

Functional Mapping of Dynamic Traits with Robust t-Distribution

Functional mapping has been a powerful tool in mapping quantitative trait loci (QTL) underlying dynamic traits of agricultural or biomedical interest. In functional mapping, multivariate normality is often assumed for the underlying data distribution, partially due to the ease of parameter estimation. The normality assumption however could be easily violated in real applications due to various reasons such as heavy tails or extreme observations. Departure from normality has negative effect on testing power and inference for QTL identification. In this work, we relax the normality assumption and propose a robust multivariate -distribution mapping framework for QTL identification in functional mapping. Simulation studies show increased mapping power and precision with the distribution than that of a normal distribution. The utility of the method is demonstrated through a real data analysis

The EADGENE Microarray Data Analysis Workshop (Open Access publication)

Microarray analyses have become an important tool in animal genomics. While their use is becoming widespread, there is still a lot of ongoing research regarding the analysis of microarray data. In the context of a European Network of Excellence, 31 researchers representing 14 research groups from 10 countries performed and discussed the statistical analyses of real and simulated 2-colour microarray data that were distributed among participants. The real data consisted of 48 microarrays from a disease challenge experiment in dairy cattle, while the simulated data consisted of 10 microarrays from a direct comparison of two treatments (dye-balanced). While there was broader agreement with regards to methods of microarray normalisation and significance testing, there were major differences with regards to quality control. The quality control approaches varied from none, through using statistical weights, to omitting a large number of spots or omitting entire slides. Surprisingly, these very different approaches gave quite similar results when applied to the simulated data, although not all participating groups analysed both real and simulated data. The workshop was very successful in facilitating interaction between scientists with a diverse background but a common interest in microarray analyses

Analysis of the real EADGENE data set: Comparison of methods and guidelines for data normalisation and selection of differentially expressed genes (Open Access publication)

A large variety of methods has been proposed in the literature for microarray data analysis. The aim of this paper was to present techniques used by the EADGENE (European Animal Disease Genomics Network of Excellence) WP1.4 participants for data quality control, normalisation and statistical methods for the detection of differentially expressed genes in order to provide some more general data analysis guidelines. All the workshop participants were given a real data set obtained in an EADGENE funded microarray study looking at the gene expression changes following artificial infection with two different mastitis causing bacteria: Escherichia coli and Staphylococcus aureus. It was reassuring to see that most of the teams found the same main biological results. In fact, most of the differentially expressed genes were found for infection by E. coli between uninfected and 24 h challenged udder quarters. Very little transcriptional variation was observed for the bacteria S. aureus. Lists of differentially expressed genes found by the different research teams were, however, quite dependent on the method used, especially concerning the data quality control step. These analyses also emphasised a biological problem of cross-talk between infected and uninfected quarters which will have to be dealt with for further microarray studies

Towards Hybrid LES-RANS-Coupling for Complex Flows with Separation

The paper is concerned with a new hybrid LES–RANS approach, which splits up the simulation into a near–wall RANS part and an outer LES part, both modes relying on a one–equation model for the turbulent kinetic energy. This model has been tested on the standard plane channel flow test case as well as on the flow over a periodic arrangement of hills. Encouraging results were achieved. In an additional study based on the detached–eddy simulation (DES) concept attempts have been made to improve the accuracy of the simulation by using adaptive local grid refinement. For this purpose, a criterion based on the residual of the budget of the mean momentum equations has been studied

Microbial and chemical markers: runoff transfer in pig and cow manure-amended soils

1 p.Fecal pollution affects environmental waters through spreading of animal manure and runoff of agricultural soils. However, the indicator bacteria (E. coli and enterococci) do not identify the source of the contamination and the development of fecal source tracking tools is crucial for water management and remediation. The aim of our study was to evaluate the transfer of chemical and microbial fecal markers during a runoff simulation on an agricultural plot previously spread with bovine or pig manure. Four types of markers have been analysed: 15 fecal sterols and stanols quantified by gas chromatography-mass spectrometry, chemical fingerprint obtained by 3D-fluorescence excitation-matrix spectroscopy, F-specific RNA specific bacteriophages (FRNAPH) and bacterial markers belonging to the Bacteroidales (Rum-2bac and Pig-2-Bac) and to the species Lactobacillus amylovorus. The results show that animal FRNAPH genogroups, sitostanol/coprostanol and cholestanol/cholesterol steroids ratios and tryptophan/ fulvic-like fluorescence differentiated pig and bovine fecal contamination. Sitostanol/coprostanol > 1 and cholestanol / cholesterol 1 are characteristic of pig manure amended plot. L-amylovorus and Pig2-bac were only present in runoff water collected on pig manure amended plot whereas Rum2-bac was only detected in runoff water collected on bovine manure amended plot. Combined analyses of chemical and microbial markers provide relevant information on the determination of fecal contamination during runoff on agricultural soils. The next step is to test the applicability of these markers in watercourses submitted to nonpoint source fecal pollution

Control of iron activity in soil solutions in hydromorphic soils by equilibrium with the "fougerite" green rust mineral

National audienc

Fe control in soil solutions in hydromorphic soils by equilibrium with the "fougerite" green rust mineral

National audienc

Use of fluorescence to trace DOM sources in a headwater agricultural catchment

International audienc