Hernandez-Raquet G.,French National Institute for Agricultural Research |
Hernandez-Raquet G.,University and oacute |
Durand E.,French National Institute for Agricultural Research |
Braun F.,French National Institute for Agricultural Research |
And 2 more authors.
Environmental Microbiology Reports | Year: 2013
Microbial diversity is generally considered as having no effect on the major processes of the ecosystem such as respiration or nutrient assimilation. However, information about the impact of diversity on minor functions such as xenobiotic degradation is scant. We studied the role of diversity on the capacity of an activated-sludge microbial community to eliminate phenanthrene, a polycyclic aromatic hydrocarbon. We also assessed the impact of diversity erosion on the ability of activated sludge to oxidize a wide range of organic compounds. The diversity of activated sludge was artificially modified by dilution to extinction followed by regrowth stage which led to communities with similar biomass but displaying a diversity gradient. The capacity of activated-sludge community to degrade phenanthrene was greatly modified: at high levels of diversity, the community was able to mineralize phenanthrene whereas at medium levels it first of all partially lost its ability to mineralize this pollutant and at the lowest diversity, the activated sludge completely lost its capacity to transform phenanthrene. Diversity depletion also reduced the metabolic diversity and biomass productivity of sewage-activated sludge. This study demonstrates that diversity erosion can greatly affect major ecosystem services such as pollutant removal. © 2013 John Wiley & Sons Ltd and Society for Applied Microbiology.
Mazat J.-P.,University and oacute |
Beauvoit B.,French National Institute for Agricultural Research
Advances in Botanical Research | Year: 2013
There are several theoretical approaches to metabolism. Some of them give a greater place to the structure of the metabolic network symbolized by its stoichiometry matrix. The constraints in a metabolic network are very strong so that a lot of information can be derived from the stoichiometry matrix without any knowledge of the kinetic parameters of its steps, such that the elementary flux modes and even in some cases, the values of fluxes by the flux balance analysis method. However, a deeper understanding of metabolic network necessitates the values of the kinetic parameters. It is particularly the case for a fine determination of the fluxes taking into account the metabolic regulations and of the determination of the flux and metabolites control coefficients. A short presentation of softwares and tools that can be used in the study of metabolic networks is presented at the end of this chapter. © 2013 Elsevier Ltd.
Korrida A.,University and oacute |
Gutierrez J.P.,Complutense University of Madrid |
Aggrey S.E.,University of Georgia |
Amin-Alami A.,University and oacute
Zoo Biology | Year: 2013
A Moroccan Houbara Bustard pedigree was analyzed to evaluate the genetic variability in captive breeding population using genealogical approaches. The whole Houbara breeding flock (WP) for the period 1993-2004 was made up of 531 birds comprising 346 females and 185 males. The reference population (RP) comprised 198 individuals ready for reproduction from 2000 to 2004 cohorts. The corresponding percentage of known ancestors was estimated as 98.23% for the parent generation, 41.19% for the grandparent generation and 7.00% for the great grandparents generation. The average generation interval for Houbara was computed as 4.64 years. Genetic variability loss per generation was ascertained using the effective population size (Ne), the founder genome equivalent (fge), the effective number of ancestors and founders (fa) and (fe), respectively, for the RP and across each cohort. The results showed no bottleneck events in the breed but some loss of genetic variability just after the initiation of the conservation program. However, the annual effective population size based on the realized increase in inbreeding (ΔF-) was estimated to be 207 for the RP and 1,000 for the WP. With regard to conservation breeding schemes, the genealogical evidence presented here is very useful as it revealed the positive effect of migration on Houbara breeding. The mating strategies will assist in the future control and management of the genetic variability of this population. © 2012 Wiley Periodicals, Inc.
Fourati M.,University and oacute |
Roig V.,University and oacute |
Raynal L.,French Institute of Petroleum
Chemical Engineering Science | Year: 2013
In order to optimize the design of gas-liquid packed columns used in distillation or in absorption processes, it is of high importance to be able to predict liquid dispersion. Indeed, dispersion phenomena will impact the choice and design of liquid distributing devices and the height of the packed beds. For this, one mainly relies on industrial feedback and on some experimental results obtained at laboratory scale which cannot be directly extrapolated since their geometric characteristics are at least one order of magnitude less than industrial columns in terms of columns diameter and height. To fill this gap CFD simulation tools should be more used since they can apply to any scale. However the latter option requires adequate modeling in particular for dispersion forces which are little studied due to the lack of data for validation. The present paper aims at developing, from original dispersion experimental measurements, closure laws that can be implemented in CFD codes. Liquid spreading from a source point has been investigated for Mellapak 250.X packing via gamma-ray tomography measurements. Closure laws are discussed from a simple 1D model which enables to go further within the Eulerian two-fluid framework with original user-defined functions and associated models that take into account liquid dispersion in the packed bed. The latter is modeled as a porous medium with appropriate closure laws. The comparison between experiments and CFD results shows that the present approach is adequate and should be further developed in order to be more precise and adapted to more packings. © 2013 Elsevier Ltd.
Detriche S.,University and oacute |
Breheret J.-G.,University and oacute |
Karrat L.,University Sidi Mohammed Ben Abdellah |
Hinschberger F.,University and oacute |
Macaire J.-J.,University and oacute
Sedimentology | Year: 2013
The Lake Afourgagh sediment record and facies successions provide an outstanding example of environmentally controlled carbonate sedimentation. Afourgagh is a small, shallow permanent lake located in the Middle-Atlas Mountains in Morocco in a karstic context. It is fed by ground waters that are relatively enriched in Mg resulting from the leaching of the Jurassic dolomitic bedrock of the catchment. This eutrophic lake is episodically restricted and characterized by alkaline waters with a fluctuating high Mg/Ca ratio. The maximum extension of the Holocene shoreline coincides with evidence of a lake stabilization level corresponding to the outflow of the lake through a wadi. Lakeshore terrace sediments deposited on an alluvial fan siltstone during the past ca 2500 cal yr bp comprise four main facies: a littoral crust, palaeosols, palustrine silts and charophyte tufas, which reflect different environments from the shoreline toward the deeper water. In the more distal parts, the charophyte tufas display a well-expressed lamination punctuated by the development of microstromatolites on algae thalli. The mineralogical composition of the carbonates is linked to the facies. While the charophyte tufas are characterized by a relatively high content in aragonite, in addition to low-Mg calcite, the littoral crust is mainly composed of magnesite. This pattern is related to the evolving chemistry of water due to the influence of charophyte proliferation during dry summers. Calcium-carbonate precipitation on algae thalli (both bioinduced and microbially mediated) progressively induces an increase in the Mg/Ca ratio of the lake water, while the capillary evaporation of shallow ground waters causes precipitation of a magnesite precursor on the shoreline, producing magnesite during early diagenesis. This effect is characteristic of two episodes: part of the Roman Warm Period and the beginning of the Dark Age Cold Period. The carbonate mineralogy of the different depositional sequences at Afourgagh indicates lake-level and water-chemistry fluctuations under a climatic influence. Therefore, among other regional records, the Lake Afourgagh sedimentary record provides useful evidence for reconstructing these environmental changes. © 2013 The Authors. Journal compilation © 2013 International Association of Sedimentologists.
Sharif T.,University and oacute |
Stambouli M.,University and oacute |
Burrus B.,University and oacute |
Emhemmed F.,University and oacute |
And 5 more authors.
Journal of Functional Foods | Year: 2013
A diet rich in plant-derived products is expected to have anticancer chemopreventive effects by acting on the appearance and growth of cancer stem cells (CSCs). Thus the effects of Aronia melanocarpa juice (AMJ) on the mouse embryonal carcinoma (EC) stem cell line P19 were investigated. AMJ inhibited cell proliferation, induced cell cycle arrest in S phase and triggered apoptosis. A pronounced upregulation of tumour suppressors p53 and p73 was observed in association with caspase-3 activation and a downregulation of the anti-apoptotic protein UHRF1 and the stemness factor Oct-4. Overall the results strongly suggest that AMJ is functionally able to counteract the carcinogenesis process by targeting CSCs. Interestingly AMJ selectively kills undifferentiated EC cells, without significant effects on normal restricted pluripotent cells (i.e. NIH/3T3 fibroblasts) or even differentiated EC cells. This argues that a differentiation therapy might normalize the pathological phenotype of a CSC which becomes insensitive to further plant-derived pharmacological treatment. © 2013 Elsevier Ltd.
Domede N.,University and oacute |
Sellier A.,University and oacute |
Stablon T.,University and oacute
Engineering Structures | Year: 2013
The paper presents a structural analysis by means of an orthotropic damage model of a multi-span masonry railway bridge built in the early years of the 20th century. Its aim is to show how this type of model allows for the current bridge mechanical behaviour under service loads to be assessed and the ultimate load to be forecast. It includes a phase of research on archived documents, an in situ investigation phase, an experimental phase carried out on core samples in the laboratory, and a computation phase. Among the different calculation steps, a simulation of the bridge history is performed in order to consider the current cracked state induced by support settlement. In a following step, the traffic loads are applied to assess the mechanical behaviour of the bridge under service loads up to failure. The mechanical behaviour of masonry is described by means of an original 3D anisotropic damage model able to consider the opening and the progressive reclosing of localized cracks. The model uses homogenized parameters considering the weakness of the stone-mortar interface. It has the capability to use material pre-damage. The calculation determines the crack pattern induced in the bridge by support displacements and loads. The support displacement study consists of an inverse analysis aimed at determining the actual present state of the structure from the cracking pattern observed on the bridge. The methodology highlights the importance of considering the whole history of a masonry structure when assessing the current state. © 2013 Elsevier Ltd.
Richard T.,University and oacute |
Temsamani H.,University and oacute |
Cantos-Villar E.,Institute Investigacio and oacute |
Monti J.-P.,University and oacute
Advances in Botanical Research | Year: 2013
An overview of advancements and applications of liquid chromatography coupled to nuclear magnetic resonance (LC-NMR) is given and discussed for secondary metabolites in the plant kingdom: terpenoids, alkaloids and phenolic compounds. The different LC-NMR operating modes are presented in order to structure compound elucidation. On-flow and stop-flow modes are described, together with technical improvements such as LC-SPE-NMR and capLC-NMR. Synergetic combination of hyphenated techniques coupled to mass spectrometry and NMR is illustrated and discussed with an example. © 2013 Elsevier Ltd.
Semmar N.,French Institute of Health and Medical Research |
Semmar N.,University and oacute
Advances in Botanical Research | Year: 2013
The metabolism is a complex system interacting with several intrinsic and extrinsic factors of biological organisms, viz. genome expressions, physiological states, environmental conditions, etc. This multifactorial interaction means that the metabolism works as a reactive and flexible system providing reliable biochemical pictures on the effects of different governing factors. Metabolic flexibility and reliability are linked to conservation laws, constraining the metabolism to a close system linking input (resources) to output (products) signals: any entering signal will be decomposed into weighted parts through different metabolic pathways. This gives to metabolic trends different functional degrees highlighted by different relative levels of metabolites. Sharing the same unit resource, the different metabolic pathways are statistically constrained to be regulated within a simplex space characterized by a unit sum of its components. Output metabolic responses and their inside regulatory processes can be analyzed by using two simplex-based approaches: correspondence analysis (CA) and weighted metabolic profiles analysis (WMPA), respectively. These two approaches are based on two opposite (complementary) principles consisting of decomposition and combination of metabolic variability. In CA, metabolic datasets are decomposed into extreme trends representing elementary components of metabolic polymorphism called metabotypes. In WMPA, iterated combinations between different metabolic components help to extract functional information on their generator backbone system. © 2013 Elsevier Ltd.
Pekarek Doehler S.,University and oacute |
Horlacher A.-S.,University and oacute
Journal of Pragmatics | Year: 2013
This paper investigates syntactic pivot patterns in French talk-in-interaction. In our data, pivot patterns recurrently amalgamate what has classically been called 'left dislocation' and 'right dislocation', as in the following: ça je vais les prendre les feuilles 'thesei I will take themi the papersi'. Here, the pivotal element (je vais les prendre 'I will take them') consists of a clause; the pre- and the post-pivot are each composed of an NP (ça and les feuilles, respectively) that is co-indexed by means of a pronoun (les 'them') within the pivot-clause. The paper investigates the interactional work that speakers accomplish through the [NP-clause-NP] pivot pattern. Results show that this pattern is routinized to different degrees for different interactional purposes: while speakers employ sedimented formats for proffering assessments, they configure the pivot pattern ad hoc for managing reference formulation. In the latter case, the pattern is patched together on-line, incrementally, following an emergent trajectory by means of which speakers respond to interactional contingencies on a moment-to-moment basis. We conclude that pivot patterns can be understood as processual products, adapted in the very course of their production to the contingencies of talk-in-interaction. As such, they are part of an emerging grammar for all practical proposes. © 2013.