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Montpellier, France

The University of Montpellier was a French university in Montpellier Hérault, in Languedoc-Roussillon region in south-east France. Its present-day university legacy has been renamed and is currently known as the University of Montpellier 1, Montpellier 2 University and Paul Valéry University, Montpellier III until 2015 when l'université de Montpellier was created a second time. Moreover, the prestigious and famous secondary high-school Lycée Joffre is also a direct heir from the outstanding Montpellier University system. Wikipedia.

Gravel D.,University of Quebec at Rimouski | Guichard F.,McGill University | Hochberg M.E.,Montpellier University
Ecology Letters | Year: 2011

The contribution of deterministic and stochastic processes to species coexistence is widely debated. With the introduction of powerful statistical techniques, we can now better characterise different sources of uncertainty when quantifying niche differentiation. The theoretical literature on the effect of stochasticity on coexistence, however, is often ignored by field ecologists because of its technical nature and difficulties in its application. In this review, we examine how different sources of variability in population dynamics contribute to coexistence. Unfortunately, few general rules emerge among the different models that have been studied to date. Nonetheless, we believe that a greater understanding is possible, based on the integration of coexistence and population extinction risk theories. There are two conditions for coexistence in the presence of environmental and demographic variability: (1) the average per capita growth rates of all coexisting species must be positive when at low densities, and (2) these growth rates must be strong enough to overcome negative random events potentially pushing densities to extinction. We propose that critical tests for species coexistence must account for niche differentiation arising from this variability and should be based explicitly on notions of stability and ecological drift. © 2011 Blackwell Publishing Ltd/CNRS.

Besnard E.,Functional Genomics Institute | Besnard E.,Gladstone | Babled A.,Functional Genomics Institute | Lapasset L.,Functional Genomics Institute | And 6 more authors.
Nature Structural and Molecular Biology | Year: 2012

DNA replication is highly regulated, ensuring faithful inheritance of genetic information through each cell cycle. In metazoans, this process is initiated at many thousands of DNA replication origins whose cell type-specific distribution and usage are poorly understood. We exhaustively mapped the genome-wide location of replication origins in human cells using deep sequencing of short nascent strands and identified ten times more origin positions than we expected; most of these positions were conserved in four different human cell lines. Furthermore, we identified a consensus G-quadruplex-forming DNA motif that can predict the position of DNA replication origins in human cells, accounting for their distribution, usage efficiency and timing. Finally, we discovered a cell type-specific reprogrammable signature of cell identity that was revealed by specific efficiencies of conserved origin positions and not by the selection of cell type-specific subsets of origins. © 2012 Nature America, Inc. All rights reserved.

Rousset F.,Montpellier University
Evolution | Year: 2015

A general version of inclusive fitness based on regression is rederived with minimal mathematics and directly from the verbal interpretation of its terms that motivated the original formulation of the inclusive fitness concept. This verbal interpretation is here extended to provide the two relationships required to determine the two coefficients -c and b. These coefficients retain their definition as expected effects on the fitness of an individual, respectively of a change in allelic state of this individual, and of correlated change in allelic state of social partners. The known least-squares formulation of the relationships determining b and c can be immediately deduced and shown to be equivalent to this new formulation. These results make clear that criticisms of the mathematical tools (in particular least-squares regression) previously used to derive this version of inclusive fitness are misdirected. © 2015, Society for the Study of Evolution.

Bouallegue F.B.,Montpellier University
Journal of Computer Assisted Tomography | Year: 2013

ABSTRACT: In this article, we propose a quantification methodology for estimating the statistical parameters of the activity inside regions of interest (ROIs). Macroquantification implies a rearrangement of the emission projection data into macroprojections and a redefinition of the system matrix based either on an image reconstruction involving iterative ROI-wise regularization or on an ROI uniformity assumption. The technique allows a very fast computation of the ROI activities and covariance matrix in the least squares sense using a low-dimensional model of the tomographic problem. The macroquantification approach is evaluated through Monte Carlo simulations using a numerical thorax phantom, without taking into account the measurement artifacts and assuming a perfect a priori ROI definition. Various tumor ROI configurations and count rates are considered to reflect clinical situations. The results show that our technique yields low-bias ROI estimations that turn out to be more accurate than classical estimates relying on pixel summation. Macroquantification also provides an approximation for the ROI variance that describes the effective variance obtained through the simulations fairly well. The technique is then validated using single photon emission computed tomography (SPECT) data from a physical phantom composed of cylinders filled with different Tc concentrations for the task of ROI comparison. Here again, the study shows excellent agreement between the measured and predicted values of the ROI variance resulting in efficient estimations of ROI ratios and highly accurate ROI comparisons. In its simplest formulation, macroquantification has a short computation time, making it an ideal technique for quantitative ROI assessment that is compatible with a wide range of routine clinical applications. © 2013 Lippincott Williams & Wilkins.

Dimeglio A.,Montpellier University | Canavese F.,Estaing University Hospital Center
Journal of Pediatric Orthopaedics Part B | Year: 2012

The French method, also called the functional physical therapy method, is a combination of physiotherapy, splinting and surgery à la carte. The French functional physical therapy method consists of daily manipulations of the newborn's clubfoot by a specialized physical therapist, stimulation of the muscles around the foot and temporary immobilization of the foot with elastic and nonelastic adhesive taping. Physiotherapy is optimized by early triceps surae lengthening. Sequences of plaster can also be used. If conservative treatment is no longer effective, surgery should be considered. Mini-invasive surgery is a complementary procedure to nonoperative treatment (surgery 'à la carte'). The French method reduces but does not eliminate the need for mini-invasive surgical procedures. Equinus is the most difficult deformity to treat; posterior release is sometimes necessary in a severe foot. Very severe feet (stiff-stiff; score, 16-20) are still a challenge. However, regular manipulations and splinting improve foot morphology and stiffness, and, ultimately, make surgery easier and less extensive. From the French method to the Ponseti method, the Hybrid method or the 'the third way', combining the advantages of both methods, is the future. The primary reason for relapses is the inability of families to maintain the correction initially achieved. The aim of this work is to provide an overview of the French functional physical therapy method and to help understand how it has evolved over time. © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Edee K.,CNRS Pascal Institute | Guizal B.,Montpellier University
Journal of the Optical Society of America A: Optics and Image Science, and Vision | Year: 2013

In this paper we present an extension of the modal method by Gegenbauer expansion (MMGE) [J. Opt. Soc. Am. A 28, 2006 (2011)], [Progress Electromagn. Res. 133, 17 (2013)] to the study of nonperiodic problems. The nonperiodicity is introduced through the perfectly matched layers (PMLs) concept, which can be introduced in an equivalent way either by a change of coordinates or by the use of a uniaxial anisotropic medium. These PMLs can generate strong irregularities of the electromagnetic fields that can significantly alter the convergence and stability of the numerical scheme. This is the case, e.g., for the famous Fourier modal method, especially when using complex stretching coordinates. In this work, it will be shown that the MMGE equipped with PMLs is a robust approach because of its natural immunity against spurious modes. © 2013 Optical Society of America.

Raffi F.,University of Nantes | Reynes J.,Montpellier University
Journal of Antimicrobial Chemotherapy | Year: 2014

Guidelines for the preferred choice of initial combination antiretroviral therapy in those living with HIV are provided by several national and international committees. Following the recent presentation of the 2013 French guidelines on antiretroviral therapy, there has been a debate regarding whether and/or how economics should influence guideline decisions and to what extent this should counterbalance valid scientific evidence.We discuss here the reasons for the unique nature of some of the proposals made by the French guidelines panel. Indeed, some recommendations are debatable. In the new French guidelines, economic considerations significantly influence and, in some instances, take precedence over the scientific evidence, leading to guidelines that are significantly different from those of other national and international committees ©The Author 2014. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved.

Two research subjects in geosciences which lately underwent significant progress are treated in this review. In the first part, we focus on one key ingredient for the numerical approximation of the Darcy flow problem, namely the discretization of diffusion terms on general polygonal/polyhedral meshes. We present different schemes and discuss in detail their fundamental numerical properties such as stability, consistency, and robustness. The second part of the paper is devoted to error control and adaptivity for model problems in geosciences. We present the available a posteriori estimates guaranteeing the maximal overall error and show how the different error components can be identified. These estimates are used to formulate adaptive stopping criteria for linear and nonlinear solvers, time step choice adjustment, and adaptive mesh refinement. Numerical experiments illustrate such entirely adaptive algorithms. © 2014 IFP Energies nouvelles.

Schultz R.A.,ConocoPhillips | Soliva R.,Montpellier University
International Journal of Fracture | Year: 2012

Propagation energies for five examples of deformation bands in porous sandstones from four field sites in Nevada, Utah, and France were calculated by using the J -integral approach. Pure compaction bands that accommodate primarily closing displacements from the Valley of Fire (Nevada) site have a closing-mode band propagation energy of JI = 5.5 ± 1.6kJ/m 2. Shear-enhanced compaction bands having subequal amounts of normal (closing) and shear strains across them from the same site have propagation energies of JI = 6.11 ± 1.8kJ/m 2 and JII = 1.52 ± 0.5kJ/m 2 for closing and shearing modes respectively. Closing- and shearing-mode band propagation energies for shear-enhanced compaction bands from the Buckskin Gulch (Utah) site, 5.63±1.7 and 1.91 ± 0.57 kJ/m 2 and the Uchaux (France) site, 11.0 ± 3.3 and 2.35 ± 0.7kJ/m 2 respectively are comparable to the values for similar structures from the Valley of Fire site. Cataclastic deformation bands at the Orange (France) site accommodate significantly larger values of shear offset than do shear-enhanced compaction bands, with a ratio of shear to closing offset that exceeds 7. The calculated closing- and shearing-mode propagation energies for these shear bands, 17.8±5.4 and 3.3 ± 1.0 kJ/m 2 respectively are comparable to those for pure or shear-enhanced compaction bands deformed at approximately the same depth of burial. Strain softening of cataclastic compactional shear bands implies unstable shearing, whereas stable and perhaps strain-hardening shearing may be inferred for shear-enhanced compaction bands. Displacement length scaling relations for shear-enhanced compaction bands of the form D ∝ √ L are consistent with the results and with suggestions of band thickening during growth obtained from bifurcation analyses and with field observations of shear zones in porous host rock. © Springer Science+Business Media B.V. 2012.

Desbrosses G.J.,Montpellier University | Stougaard J.,University of Aarhus
Cell Host and Microbe | Year: 2011

Legume plants have an exceptional capacity for association with microorganisms, ranging from largely nonspecific to very specific interactions. Legume-rhizobial symbiosis results in major developmental and metabolic changes for both the microorganism and host, while providing the plant with fixed nitrogen. A complex signal exchange leads to the selective rhizobial colonization of plant cells within nodules, new organs that develop on the roots of host plants. Although the nodulation mechanism is highly specific, it involves the same subset of plant phytohormones, namely auxin, cytokinin, and ethylene, which are required for root development. In addition, nodulation triggered by the rhizobia affects the development of the host root system, indicating that the microorganism can alter host developmental pathways. Nodulation by rhizobia is a prime example of how microorganisms and plants have coevolved and exemplifies how microbial colonization may affect plant developmental pathways. © 2011 Elsevier Inc.

Gullaud E.,European Center for Research and Advanced Training in Scientific Computation | Nicoud F.,Montpellier University
AIAA Journal | Year: 2012

This paper aims to show the influence of perforated plates on the acoustic modes in aeronautical gas turbine combustion chambers. The analytical model was implemented in a three-dimensional acoustic Helmholtz solver to account for the effect of perforated plates. First, an analytic test case is used to validate the coding in the acoustic solver. Then, a computation of the acoustic modes in an actual industrial chamber is conducted, taking into account the perforated liners. For both cases, a study of the influence of the bias flow speed is conducted. The acoustic energy budget is also used to evaluate the respective contributions of the perforated plates. In the case of the industrial chamber, some plates are proved to be more effective than the others, depending on the mode structure. Copyright © 2012 by the American Institute of Aeronautics and Astronautics, Inc.

Carles R.,Montpellier University
Archive for Rational Mechanics and Analysis | Year: 2012

We consider the Hartree equation with a smooth kernel and an external potential, in the semiclassical regime. We analyze the propagation of two initial wave packets and show different possible effects of the interaction, according to the size of the nonlinearity in terms of the semiclassical parameter. We show three different sorts of nonlinear phenomena. In each case, the structure of the wave as a sum of two coherent states is preserved. However, the envelope and the center (in phase space) of these two wave packets are affected by nonlinear interferences, which are described precisely. © 2012 Springer-Verlag.

Boulenger J.-P.,Montpellier University | Loft H.,Lundbeck | Florea I.,Lundbeck
Journal of Psychopharmacology | Year: 2012

The efficacy and tolerability of Lu AA21004 in the prevention of relapse of major depressive disorder (MDD) in patients in remission after acute treatment was evaluated. Patients (n=639) aged 18-75 years with a primary diagnosis of MDD with a current major depressive episode (MDE) ≥4 weeks' duration, at least one prior MDE and a MADRS total score ≥26 received 12-week, open-label Lu AA21004 at 5 or 10mg/day. Patients in remission (MADRS ≥10) at both weeks 10 and 12 were assigned to double-blind treatment with either placebo or Lu AA21004 (fixed dose from Week 8).Patients (n=396) were treated, after random assignment to placebo (n=192) or Lu AA21004 (n=204). The primary analysis of time to relapse (full-analysis set, Cox proportional hazard model) showed a statistically significant difference in favour of Lu AA21004 versus placebo with a hazard ratio of 2.01 (95% confidence interval: 1.26-3.21; p=0.0035). The proportion of patients who relapsed was 13% in the Lu AA21004 group (n=27) and 26% in the placebo group (n=50). The withdrawal rates due to adverse events were 8% (open-label), and 3% (placebo) and 8% (Lu AA21004) (double-blind). Thus, Lu AA21004 was effective in preventing relapse of MDD and was well tolerated as maintenance treatment. © The Author(s) 2012.

Vasileiou V.,Montpellier University
Astroparticle Physics | Year: 2013

The proper estimation of the background is a crucial component of data analyses in astrophysics, such as source detection, temporal studies, spectroscopy, and localization. For the case of the Large Area Telescope (LAT) on board the Fermi spacecraft, approaches to estimate the background for short (≠© 2013 Elsevier Inc. All rights reserved.

De Witt Hamer P.C.,VU University Amsterdam | Moritz-Gasser S.,Montpellier University Hospital Center | Gatignol P.,University of Paris Descartes | Duffau H.,Montpellier University Hospital Center | Duffau H.,Montpellier University
Human Brain Mapping | Year: 2011

Human brain pathways required for language processing are poorly known. A new white matter tract in humans, the middle longitudinal fascicle, has recently been anatomically determined by diffusion tensor imaging and suggested to be essential for language. Our aim is to determine the importance of the middle longitudinal fascicle for language processing. This study is based on 8 patients with glioma resection at least involving the superior temporal gyrus of the left dominant hemisphere. Language is systematically examined pre- and postoperatively at 3 months. Intraoperative electrostimulation is used to map cortical and subcortical structures as functional boundaries of the glioma resection, including those essential for language processing. The resections are extensive (on average 62 ml, ranging from 21 to 111 ml) and include a large part of the middle longitudinal fascicle in all patients. Intraoperatively, no interference with picture naming is observed by electrostimulation of the middle longitudinal fascicle, while in all patients the inferior fronto-occipital fascicle is identified by eliciting semantic paraphasia as functional boundary. Postoperatively, no new permanent language deficits are detected by systematic language examination. Therefore, we suggest that the middle longitudinal fascicle may participate but is not essential for language processing. © 2010 Wiley-Liss, Inc.

Feil R.,Montpellier University | Fraga M.F.,CSIC - National Center for Biotechnology | Fraga M.F.,University of Oviedo
Nature Reviews Genetics | Year: 2012

Epigenetic phenomena in animals and plants are mediated by DNA methylation and stable chromatin modifications. There has been considerable interest in whether environmental factors modulate the establishment and maintenance of epigenetic modifications, and could thereby influence gene expression and phenotype. Chemical pollutants, dietary components, temperature changes and other external stresses can indeed have long-lasting effects on development, metabolism and health, sometimes even in subsequent generations. Although the underlying mechanisms remain largely unknown, particularly in humans, mechanistic insights are emerging from experimental model systems. These have implications for structuring future research and understanding disease and development. © 2012 Macmillan Publishers Limited. All rights reserved.

Petit A.S.,Montpellier University | Harvey J.N.,University of Bristol
Physical Chemistry Chemical Physics | Year: 2012

The overall rate coefficient at standard temperature and pressure for the hydrogen abstraction reaction by the hydroxyl radical (HO) from common saturated volatile organic compounds (VOCs) is derived theoretically using electronic structure calculations and transition state theory (TST). The computational approach used is based on relatively efficient methods, and hence is applicable to a large number of compounds with only a modest use of computer resources. The key methods used are density functional theory (for the calculation of barrier heights) and simple transition state theory (TST), including a simple correction for tunnelling. All thermally relevant conformers of the reactant and the abstraction TS are included in the study. For all compounds in a test set of thirty-four, the calculated rate coefficient agrees with the experimental value to within better than an order of magnitude, and to within better than a factor of three for all but six cases, so that the accuracy is of predictive utility.

Gleyse J.,Montpellier University
Scandinavian Journal of Medicine and Science in Sports | Year: 2013

The long history of the conception of physical exercise in France may be viewed as a function of a series of changes in understanding the body. Scientific concepts were used to present the body in official texts by authors specializing in the subject, or to describe them, as did Michel Foucault, as epistemic changes. A departure occurred during the 19th century that is clearly demonstrated in the writings of Gustave Adolphe Hirn. This breakthrough concerned the idea of considering the organism as an energy-generating machine. This metaphor was employed in describing the body during physical exercise from the 17th to the 19th centuries, when the body was thought of as mechanical. Such metaphors were used by the most relevant figures writing at the end of the 19th century in the rationale that is examined in this paper. It shows how Hirn, Marey, Lagrange, Demenij, Hebert, and Tissié saw the body and how they employed machine metaphors when referring to it. These machine metaphors are analyzed from the time of their scientific and technological origins up to their current use in physical and sports education. This analysis will contribute to the understanding of how a scientific metaphor comes to be in common use and may lead to particular exercise practices. © 2012 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Mertes P.M.,Nancy University Hospital Center | Demoly P.,Montpellier University | Malinovsky J.M.,Nancy University Hospital Center
Current Opinion in Allergy and Clinical Immunology | Year: 2012

PURPOSE OF REVIEW: Immediate hypersensitivity reactions are an important cause for mortality and morbidity in anesthesia. The present review considers reports covering epidemiology, diagnosis, and treatment of these reactions. RECENT FINDINGS: Immediate hypersensitivity reactions are largely under-reported, adult women being at significantly higher risk than men. The role of sex hormones associated with increased risk in adult women has been demonstrated. Neuromuscular blocking agents (NMBAs) remain the most frequently incriminated drugs. Reactions involving antibiotics, dyes, or nonsteroidal anti-inflammatory agents are reported with increasing frequency, in parallel with changing trends in clinical practice. A recent hypothesis concerning a link between pholcodine exposure and allergic reactions to NMBAs is under investigation. Detailed guidelines concerning skin testing have been provided. The use of several inotropes or vasopressor such as vasopressin is proposed in case of reactions refractory to epinephrine and volume expansion. The use of cyclodextrin to mitigate severe allergic reactions to rocuronium, by specific drug encapsulation, has been proposed. SUMMARY: Hypersensitivity reactions remain a major cause of concern in the perioperative setting. Although largely under-reported, their incidence is higher than previously reported. NMBAs remain the most frequently incriminated drug, followed by latex and antibiotics. The number of reactions involving new allergens like vital dyes or nonsteroidal anti-inflammatory drugs is rapidly increasing. The mechanism of sensitization to NMBAs could be influenced by as yet unidentified environmental factors. The possible role of pholcodine is under investigation. Several guidelines concerning the diagnosis and management of immediate hypersensitivity reactions in anesthesia are now available. © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins.

A series of 2277 Leishmania strains from Old World visceral leishmaniasis foci, isolated between 1973 and 2008, were studied by isoenzyme analysis. The strains were obtained from humans, domestic and wild carnivores, rodents and phlebotomine sandflies, and came from 36 countries. In all, 60 different zymodemes were identified and clustered by a phenetic analysis into 3 different groups corresponding to the typically visceralizing species L. donovani (20 zymodemes, 169 strains), L. archibaldi (3 zymodemes, 46 strains) and L. infantum (37 zymodemes, 2,062 strains). The taxonomic position of these isoenzymatic groups is discussed in view of contradictory results obtained from recent molecular studies.

Lissenberg C.J.,University of Cardiff | MacLeod C.J.,University of Cardiff | Howard K.A.,University of Cardiff | Godard M.,Montpellier University
Earth and Planetary Science Letters | Year: 2013

Mid-ocean ridge basalt (MORB) is the most abundant magma on Earth, and provides a geochemical window into the mantle. Deriving mantle composition and melting processes from the erupted lavas requires correction to be made for their evolution as they pass through and generate the oceanic crust. This is typically done by assuming that modification of melts in crustal magma chambers occurs exclusively by fractional crystallisation. However, extensive mineral major- and trace element data from a full section of fast-spread lower crustal rocks exposed in Hess Deep (equatorial Pacific Ocean) demonstrate that their evolution is instead controlled by reactive porous flow. These reactions lead to a strong enrichment in, and fractionation of, incompatible trace elements in the melt (as recorded by clinopyroxene compositions), leading to melt compositions far outside of the compositional realm of MORB both in terms of trace element abundances and ratios. The reactive signature increases in strength up section, peaking in varitextured gabbros interpreted to represent the fossilised axial melt lens, indicating that reactive porous flow occurred on the scale of the entire lower crust. The enrichment of the melt is coupled with a strong trace element depletion of plagioclase, olivine, and, to a lesser extent, clinopyroxene cores, suggesting that these phases represent the residues of the reactions from which trace elements have been removed. The dominant role of reactive porous flow, and the resulting deviations from fractional crystallisation predictions, suggest that the lower oceanic crust plays a much more complex and significant role in modifying the compositions of MORB than previously expected, with consequent implications for models of mantle processes. © 2012 Elsevier B.V.

Rezen T.,University of Ljubljana | Rozman D.,University of Ljubljana | Pascussi J.-M.,Montpellier University | Monostory K.,Hungarian Academy of Sciences
Biochimica et Biophysica Acta - Proteins and Proteomics | Year: 2011

Cholesterol biosynthetic and metabolic pathways contain several branching points towards physiologically active molecules, such as coenzyme Q, vitamin D, glucocorticoid and steroid hormones, oxysterols, or bile acids. Sophisticated regulatory mechanisms are involved in maintenance of the homeostasis of not only cholesterol but also other cholesterogenic molecules. In addition to endogenous cues, cholesterol homeostasis needs to accommodate also to exogenous cues that are imported into the body, such as chemicals and medications. Steroid and nuclear receptors together with sterol regulatory element-binding protein (SREBP) mediate the fine tuning of biosynthetic and metabolic routes as well as transports of cholesterol and its derivatives. Similarly, drug/xenobiotic metabolism is the subject to the feedback regulation of cytochrome P450 enzymes and transporters. The regulatory mechanisms that maintain the homeostasis of cholesterogenic molecules and are involved in drug metabolism share similarities. Cholesterol and cholesterogenic compounds (bile acids, glucocorticoids, vitamin D, etc.) regulate the xenosensor signaling in drug-mediated induction of the major drug-metabolizing cytochrome P450 enzymes. The key cellular receptors, pregnane X receptor (PXR), constitutive androstane receptor (CAR), vitamin D receptor (VDR), and glucocorticoid receptor (GR) provide a functional cross-talk between the pathways maintaining cholesterol homeostasis and controlling the expression of drug-metabolizing enzymes. These receptors serve as metabolic sensors, resulting in a coordinate regulation of cholesterogenic compounds metabolism and of the defense against xenobiotic and endobiotic toxicity. Herein we present a comprehensive review of functional interactions between cholesterol homeostasis and drug metabolism involving the main nuclear and steroid receptors. © 2010 Elsevier B.V. All rights reserved.

Piron F.,Montpellier University
Comptes Rendus Physique | Year: 2016

Gamma-Ray Bursts (GRBs) are extra-galactic and extremely energetic transient emissions of gamma rays, which are thought to be associated with the death of massive stars or the merger of compact objects in binary systems. Their huge luminosities involve the presence of a newborn stellar-mass black hole emitting a relativistic collimated outflow, which accelerates particles and produces non-thermal emissions from the radio domain to the highest energies. In this article, I review recent progresses in the understanding of GRB jet physics above 100 MeV, based on Fermi observations of bright GRBs. I discuss the physical implications of these observations and their impact on GRB modeling, and I present some prospects for GRB observation at very high energies in the near future. © 2016 Académie des sciences.

Charlier D.,Montpellier University
Energy Policy | Year: 2015

The residential sector offers considerable potential for reducing energy use and greenhouse gas (GHG) emissions, particularly through energy-efficient renovations. The objective of this study is twofold. First, I aim to provide initial empirical evidence of the extent to which split incentives between landlords and tenants may lead to underinvestment. Second, I investigate the influence of tax credits and energy burdens on energy efficiency expenditures. Given the complexity of studying the decision to invest in energy-saving renovations, I use a bivariate Tobit model to compare decisions about energy-efficient works and repair works, even when the renovation expenditures seem quite similar. The analysis shows that tenants are doubly penalized: they have high energy expenditures due to energy-inefficient building characteristics, and because they are poorer than homeowners, they are unable to invest in energy-saving systems. The results also confirm that tax credits are ineffective in the split incentives context. In terms of public policy, the government should focus on low-income tenants, and mandatory measures such as minimum standards seem appropriate. Financial support from a third-party financer also might be a solution. © 2015 Elsevier Ltd.

Jimenez-Moreno G.,University of Granada | Fauquette S.,Montpellier University | Suc J.-P.,University Claude Bernard Lyon 1
Review of Palaeobotany and Palynology | Year: 2010

Pollen analysis of Miocene and Pliocene sediments from the Iberian Peninsula shows a progressive reduction in plant diversity through time caused by the disappearance of thermophilous and high-water requirement plants. In addition, an increase in warm-temperate (mesothermic), seasonal-adapted "Mediterranean" taxa, high-elevation conifers and herbs (mainly Artemisia) occurred during the Middle and Late Miocene and Pliocene. This has mainly been interpreted as a response of the vegetation to global and regional processes, including climate cooling related to the development of the East Antarctic Ice Sheet and then the onset of the Arctic Ice Sheet, uplift of regional mountains related to the Alpine uplift and the progressive movement of Eurasia towards northern latitudes as a result of the northwards subduction of Africa. The development of steppe-like vegetation in southern Iberia is ancient and probably started during the Oligocene. The onset of a contrasted seasonality in temperature during the Mid-Pliocene superimposed on the pre-existing seasonality in precipitation, the annual length of which increased southward. The Mediterranean climatic rhythm (summer drought) began about 3.4. Ma and caused the individualization of modern Mediterranean ecosystems. Quaternary-type Mediterranean climatic fluctuations started at 2.6. Ma (Gelasian) resulting in repeated steppe vs. forest alternations. A latitudinal climatic gradient between the southern and the northern parts of the Iberian Peninsula existed since the Middle Miocene. © 2009 Elsevier B.V.

Dutheil J.Y.,Montpellier University
Briefings in Bioinformatics | Year: 2012

Positions in a molecule that share a common constraint do not evolve independently, and therefore leave a signature in the patterns of homologous sequences. Exhibiting such positions with a coevolution pattern from a sequence alignment has great potential for predicting functional and structural properties of molecules through comparative analysis. This task is complicated by the existence of additional correlation sources, leading to false predictions. The nature of the data is a major source of noise correlation: sequences are taken from individuals with different degrees of relatedness, and who therefore are intrinsically correlated. This has led to several method developments in different fields that are potentially confusing for non-expert users interested in these methodologies. It also explains why coevolution detection methods are largely unemployed despite the importance of the biological questions they address. In this article, I focus on the role of shared ancestry for understanding molecular coevolution patterns. I review and classify existing coevolution detection methods according to their ability to handle shared ancestry. Using a ribosomal RNA benchmark data set, for which detailed knowledge of the structure and coevolution patterns is available, I demonstrate and explain why taking the underlying evolutionary history of sequences into account is the only way to extract the full coevolution signal in the data. I also evaluate, using rigorous statistical procedures, the best approaches to do so, and discuss several important biological aspects to consider when performing coevolution analyses. © The Author 2011. Published by Oxford University Press.

Dimeglio A.,Montpellier University | Canavese F.,Center Hospitalier University Estaing
European Spine Journal | Year: 2012

Purpose This article aims to provide an overview of how spinal deformities can alter normal spine and thoracic cage growth. Methods Some of the data presented in this article are gathered from studies performed in 1980 and 1990, and their applicability to populations of different ethnicity, geography or developmental stage has not yet been elucidated. In the present article, older concepts have been integrated with newer scientific data available to give the reader the basis for a better understanding of both normal and abnormal spine and thoracic cage growth. Results A thorough analysis of different parameters, such as weight, standing and sitting height, body mass index, thoracic perimeter, arm span, T1-S1 spinal segment length, and respiratory function, help the surgeon to choose the best treatment modality. Respiratory problems can develop after a precocious vertebral arthrodesis or as a consequence of pre-existing severe vertebral deformities and can vary in patterns and timing, according to the existing degree of deformity. The varying extent of an experimental arthrodesis also affects differently both growth and thoracopulmonary function. Conclusions Growth is a succession of acceleration and deceleration phases and a perfect knowledge of normal growth parameters is mandatory to understand the pathologic modifications induced on a growing spine by an early onset spinal deformity. The challenges associated with the growing spine for the surgeon include preservation of the thoracic spine, thoracic cage, and lung growth without reducing spinal motion. © 2011 Springer-Verlag.

Chrysochoos A.,Montpellier University
Quantitative InfraRed Thermography Journal | Year: 2012

The characterization of material behavior under various loading conditions involves two closely related aspects, namely mechanical and thermal, that can be grouped into one general thermomechanical framework. The goal of this paper is to briefly review specific applications of infrared techniques, over a range of loading conditions, such as quasi-static and polycyclic, for various types of material. Some experimental and theoretical issues are discussed to highlight the additional knowledge that can be gained through the application of these techniques to the mechanical characterization of materials. © 2012 Taylor and Francis.

Baroux C.,University of Zurich | Autran D.,Montpellier University
Plant Journal | Year: 2015

Sexual reproduction in flowering plants offers a number of remarkable aspects to developmental biologists. First, the spore mother cells - precursors of the plant reproductive lineage - are specified late in development, as opposed to precocious germline isolation during embryogenesis in most animals. Second, unlike in most animals where meiosis directly produces gametes, plant meiosis entails the differentiation of a multicellular, haploid gametophyte, within which gametic as well as non-gametic accessory cells are formed. These observations raise the question of the factors inducing and modus operandi of cell fate transitions that originate in floral tissues and gametophytes, respectively. Cell fate transitions in the reproductive lineage imply cellular reprogramming operating at the physiological, cytological and transcriptome level, but also at the chromatin level. A number of observations point to large-scale chromatin reorganization events associated with cellular differentiation of the female spore mother cells and of the female gametes. These include a reorganization of the heterochromatin compartment, the genome-wide alteration of the histone modification landscape, and the remodeling of nucleosome composition. The dynamic expression of DNA methyltransferases and actors of small RNA pathways also suggest additional, global epigenetic alterations that remain to be characterized. Are these events a cause or a consequence of cellular differentiation, and how do they contribute to cell fate transition? Does chromatin dynamics induce competence for immediate cellular functions (meiosis, fertilization), or does it also contribute long-term effects in cellular identity and developmental competence of the reproductive lineage? This review attempts to review these fascinating questions. Significance Statement The establishment of the female reproductive lineage in flowering plants involves several cell fate transitions associated with large-scale chromatin dynamics underlying cellular reprogramming. The next challenge is to understand how chromatin dynamics functionally contributes to cell fate transition. © 2015 The Authors.

Giorgi P.,Montpellier University
IEEE Transactions on Computers | Year: 2012

In a recent paper, Lima, Panario, and Wang have provided a new method to multiply polynomials expressed in Chebyshev basis which reduces the total number of multiplication for small degree polynomials. Although their method uses Karatsuba's multiplication, a quadratic number of operations are still needed. In this paper, we extend their result by providing a complete reduction to polynomial multiplication in monomial basis, which therefore offers many subquadratic methods. Our reduction scheme does not rely on basis conversions and we demonstrate that it is efficient in practice. Finally, we show a linear time equivalence between the polynomial multiplication problem under monomial basis and under Chebyshev basis. © 1968-2012 IEEE.

Whitfield A.K.,South African Institute For Aquatic Biodiversity | Panfili J.,IRD Montpellier | Durand J.-D.,Montpellier University
Reviews in Fish Biology and Fisheries | Year: 2012

This study reviews published information on Mugil cephalus from around the world, with recent genetic studies indicating that the flathead mullet may indeed be a species complex. Disciplines that are covered range from the taxonomy, genetics and systematics, through a variety of biological and ecological attributes, to biomarker and fisheries studies. The eurytopic nature of M. cephalus is emphasized, with the migratory life history covering a succession of very different aquatic environments (e. g. rivers, estuaries, coastal lakes/lagoons, marine littoral, open ocean), each of which is occupied for varying lengths of time, depending on the population characteristics within a region and the life-history stage of the species. Interpretation of these movements over time has been greatly enhanced by the use of otolith micro-chemistry which has enabled scientists to map out the different habitats occupied by individual fish at the different life stages. The range of physico-chemical attributes within these environments necessitates a wide tolerance to differing conditions, especially with regard to salinity, turbidity, dissolved oxygen and temperature, all of which are discussed in this review. The importance of M. cephalus to the ecological functioning of coastal systems is emphasized, as well as the pivotal role that this species fulfills in fisheries in some parts of the world. The parasites range from internal trematode and cestode infestations, to external branchyuran and copepod parasites, which use M. cephalus as either an intermediate or final host. The value of the flathead mullet as a biomarker for the monitoring of the health of coastal habitats is discussed, as well as its potential as an indicator or sentinel species for certain ecosystems. © 2012 Springer Science+Business Media B.V.

Renaud S.,University Claude Bernard Lyon 1 | Auffray J.-C.,Montpellier University
Journal of Zoological Systematics and Evolutionary Research | Year: 2010

Morphometric methods allow the quantification of directions of phenotypic changes and their statistical comparison in a morphometric space. We applied this approach to investigate several candidate factors to explain changes in mandible shape occurring in house mice (Mus musculus domesticus, Mammalia, Rodentia) in Corsica and a nearby islet. The role of niche widening and of the concomitant change in diet was evaluated by comparing the micro-evolutionary insular change to the macro-evolutionary difference between omnivorous and herbivorous rodents. Phenotypic plasticity, which may contribute to rapid insular evolution, was assessed by breeding laboratory mice on hard versus soft food. The related change in mandible shape was compared with differences between continental and insular populations. The role of allometry was evaluated by assessing shape change related to size within the continental population and comparing this direction of change with differences on islands. Finally, evolution may be facilitated along the direction of the greatest phenotypic variance. This hypothesis was tested by computing in wild populations vectors corresponding to this direction and by comparing these vectors with those corresponding to estimates of shape changes related to plasticity, micro- and macro-evolutionary processes. In Corsica, the congruence in directions of macro- and micro-evolutionary phenotypic vectors (Corsican/continental mice versus omnivorous/herbivorous rodents) supports the hypothesis of adaptation in mandible shape evolution. By contrast, on the islet, phenotypic divergence follows directions of plastic response to food consistency as well as within-population allometry. Thus, results suggest differences in the relative importance of processes which may influence rodent mandibular shape depending on the size of the islands they colonized. Faster evolution and plasticity may be more evident in small and often ephemeral populations living on small islands, whereas micro-evolutionary processes may have enough time and genetic variability to progressively 'align' with macro-evolutionary trends in large populations from big islands. © 2009 Blackwell Verlag GmbH.

Richardson Y.,International Institute for Water and Environmental Engineering | Blin J.,International Institute for Water and Environmental Engineering | Blin J.,CIRAD - Agricultural Research for Development | Julbe A.,Montpellier University
Progress in Energy and Combustion Science | Year: 2012

Application of the process intensification concept to biomass gasification is relatively recent, but is arousing growing interest by providing true opportunities for developing cost-effective high quality syngas, particularly for small to medium-scale installations, adapted to the economic context of most regions in the world. In this highly swarming context towards process intensification, this article provides an overview of the different strategies which are reported in the literature to perform syngas or H 2 purification and conditioning into the gasifier. A promising avenue towards process intensification consists in integrating several functionalities into suitable fluidized bed gasifiers, such as catalytic tar cracking/reforming, CO 2 elimination, H 2 separation and the elimination of particles and other contaminants. The development of new catalytic integrated gasification concepts is also proposed to achieve high conversion performances while pursuing significant process intensification. This strategy is illustrated by relevant examples such as the design of short contact time partial oxidation catalytic reactors, the implementation of specific reaction media such as supercritical water or molten metal, or the realisation of a close contact between solid catalysts and lignocellulosic biomass. Most of these different technologies are not mature yet and research effort has to be performed for optimizing each of these approaches, calling for a multidisciplinary and multi-scale approach integrating catalysis, chemistry, reaction and process engineering. The design of new advanced gasification reactor concept still has to be pursued in order to achieve the challenging one-step production of a high quality syngas from biomass gasification. The implementation of such innovative biomass gasification breakthrough concepts could be one of the most promising ways of process intensification resulting in a significant cut down of the production costs of synthesis gas and H 2 derived from biomass. Graphical abstract: Application of the process intensification concept to biomass gasification is a promising way to cut down the production costs of synthesis gas and H 2 derived from biomass and requires a multidisciplinary and multi-scale approach integrating catalysis, chemistry, reaction and process engineering. © 2012 Elsevier Ltd. All rights reserved.

Bucher E.,University of Basel | Reinders J.,DuPont Pioneer | Mirouze M.,Montpellier University
Current Opinion in Plant Biology | Year: 2012

The mobility of genetic elements called transposable elements (TEs) was discovered half a century ago by Barbara McClintock. Although she had recognized them as chromosomal controlling elements, for much of the consequent time TEs were primarily considered as parasites of the host genome. However the recent explosion of discoveries in the fields of genomics and epigenetics have unambiguously shown the importance of TEs in genome function and evolution. Bursts of endogenous TEs have been reported in plants with epigenetic misregulation, revealing the molecular mechanisms underlying their control. We review here the different steps in TE invasion of the host genome involving epigenetic control and environmental stress responses. As TEs propagate in plant genomes and attract epigenetic marks, their neo-insertions can lead to the formation of new, heritable epigenetic variants (epialleles) of genes in their vicinity and impact on host gene regulatory networks. The epigenetic interplay between TE and genes thus plays a crucial role in the TE-host co-evolution. © 2012 Elsevier Ltd.

Fender M.L.,North Carolina State University | Lechenault F.,North Carolina State University | Lechenault F.,Montpellier University | Daniels K.E.,North Carolina State University
Physical Review Letters | Year: 2010

We investigate the origins of the widely observed "en passant" crack pattern, which forms through interactions between two approaching cracks. A rectangular elastic plate is notched on each long side and then subjected to quasistatic uniaxial strain from the short side. The two cracks propagate along approximately straight paths until they pass each other, after which they curve and release a lenticular fragment. We find that, for materials with diverse mechanical properties, the shape of this fragment has an aspect ratio of 21, with the length scale set by the initial crack offset s and the time scale set by the ratio of s to the pulling velocity. The cracks have a universal square root shape, which we understand by using a simple geometric model of the crack-crack interaction. © 2010 The American Physical Society.

Le Corre D.,Plant and Food Research Ltd. | Angellier-Coussy H.,Montpellier University
Reactive and Functional Polymers | Year: 2014

The increasing scientific and industrial interest for starch nanoparticles (SNP) has led to the development of numerous methods for preparing sub-micron starch fillers for nanocomposites applications. Starch nanocrystals (SNC), which constitute the focus of this review, are one type of SNP with crystalline property and platelet like morphology. SNC can be extracted from various starch botanical sources, allowing to obtain a large range of amylose content, shape, viscosity in suspension, surface reactivity and thermal resistance. To date, the most common method for extracting SNC remains the mild acid hydrolysis of the amorphous parts of native granular starch. So far, alternative methods render much lower yield. Since first publications on SNC, the principal aim is to use them as reinforcement in polymer matrices. Thanks to the reactive nature of starch, SNC surface can be modified by grafting or cross-linking which renders them more readily dispersible in the polymer matrix. The present review focus on the reinforcing effect and mechanisms of SNC, as well as on their impact of barrier properties of polymers. © 2014 Elsevier B.V. All rights reserved.

Ducros A.,Montpellier University | Wolff V.,University of Strasbourg
Headache | Year: 2016

During the last 10 years, reversible cerebral vasoconstriction syndrome (RCVS) has emerged as the most frequent cause of thunderclap headache (TCH) in patients without aneurysmal subarachnoid hemorrhage, and as the most frequent cause of recurrent TCHs. The typical TCHs of RCVS are multiple, recurring over a few days to weeks, excruciating, short-lived, and brought up by exertion, sexual activities, emotion, Valsalva maneuvers, or bathing, among other triggers. All these triggers induce sympathetic activation. In a minority of cases with RCVS, TCH heralds stroke and rarely death. Early diagnosis of RCVS in patients who present with isolated headache enables proper management and might reduce the risk of eventual stroke. This review describes the characteristics, triggers, diagnosis, and management of TCH in RCVS. One aim is to underline that the TCH pattern of RCVS is so typical that it enables, according to the 2013 revision of the International Classification of Headache Disorders, the diagnosis of "probable RCVS" in patients with such a headache pattern, normal cerebral angiography, and no other cause. Another objective is to discuss the role of physical and emotional stress in RCVS and in other related conditions involving similar triggers. © 2016 American Headache Society.

Picard N.,CIRAD - Agricultural Research for Development | Favier C.,Montpellier University
American Naturalist | Year: 2011

The relationship between species abundance, the variance of the number of individuals, and species occupancy is a fundamental ecological characteristic of a community. Moreover, this relationship varies across scales, and any model for the variance-occupancy-abundance (VOA) relationship has to address its scale dependency in a consistent way. In this study, point-process theory was used to define a multiscale model that jointly predicts the VOA relationship across scales in a consistent way. This provides a tool to jointly analyze data sets collected at different scales and to give insights into the biological processes underlying the VOA relationship. This model can also account for different types of individual spatial pattern (clustered, random, or regular). Three stand-mapping data sets of tree species in tropical rain forests were used to assess the relevance of this model. When compared with four existing models, the model based on point-process theory provided the best fit to the data and was the most often ranked as the model with the best predictive performance. © 2011 by The University of Chicago.

Lebon G.,Montpellier University | Warne T.,University of Cambridge | Tate C.G.,University of Cambridge
Current Opinion in Structural Biology | Year: 2012

G protein-coupled receptors (GPCRs) play a major role in intercellular communication by binding small diffusible ligands (agonists) at the extracellular surface. Agonist-binding induces a conformational change in the receptor, which results in the binding and activation of heterotrimeric G proteins within the cell. Ten agonist-bound structures of non-rhodopsin GPCRs published last year defined for the first time the molecular details of receptor activated states and how inverse agonists, partial agonists and full agonists bind to produce different effects on the receptor. In addition, the structure of the β2-adrenoceptor coupled to a heterotrimeric G protein showed how the opening of a cleft in the cytoplasmic face of the receptor as a consequence of agonist binding results in G protein coupling and activation of the G protein. © 2012.

Kajava A.V.,Montpellier University
Journal of Structural Biology | Year: 2012

The bioinformatics analysis of proteins containing tandem repeats requires special computer programs and databases, since the conventional approaches predominantly developed for globular domains have limited success. Here, I survey bioinformatics tools which have been developed recently for identification and proteome-wide analysis of protein repeats. The last few years have also been marked by an emergence of new 3D structures of these proteins. Appraisal of the known structures and their classification uncovers a straightforward relationship between their architecture and the length of the repetitive units. This relationship and the repetitive character of structural folds suggest rules for better prediction of the 3D structures of such proteins. Furthermore, bioinformatics approaches combined with low resolution structural data, from biophysical techniques, especially, the recently emerged cryo-electron microscopy, lead to reliable prediction of the protein repeat structures and their mode of binding with partners within molecular complexes. This hybrid approach can actively be used for structural and functional annotations of proteomes. © 2011 Elsevier Inc.

Alexandrov S.,Montpellier University | Persson D.,ETH Zurich | Pioline B.,University Pierre and Marie Curie
Journal of High Energy Physics | Year: 2011

We investigate quantum corrections to the hypermultiplet moduli space M in Calabi-Yau compactifications of type II string theories, with particular emphasis on instanton effects from Euclidean NS5-branes. Based on the consistency of D-and NS5-instanton corrections, we determine the topology of the hypermultiplet moduli space at fixed string coupling, as previewed in [1]. On the type IIB side, we compute corrections from (p, k)-fivebrane instantons to the metric on M (specifically, the correction to the complex contact structure on its twistor space Z) by applying S-duality to the D-instanton sum. For fixed fivebrane charge k, the corrections can be written as a non-Gaussian theta series, whose summand for k = 1 reduces to the topological A-model amplitude. By mirror symmetry, instanton corrections induced from the chiral type IIA NS5-brane are similarly governed by the wave function of the topological B-model. In the course of this investigation we clarify charge quantization for coherent sheaves and find hitherto unnoticed corrections to the Heisenberg, monodromy and S-duality actions on M, as well as to the mirror map for Ramond-Ramond fields and D-brane charges. © SISSA 2011.

Andreev S.V.,Montpellier University
Physical Review Letters | Year: 2013

We explain the experimentally observed instability of cold exciton gases and the formation of a macroscopically ordered exciton state in terms of a thermodynamic model accounting for the phase fluctuations of the condensate. We show that the temperature dependence of the exciton energy exhibits fundamental scaling behavior with the signature of the second order phase transition. © 2013 American Physical Society.

Zamponi G.W.,University of Calgary | Lory P.,Montpellier University | Perez-Reyes E.,University of Virginia
Pflugers Archiv European Journal of Physiology | Year: 2010

It is well established that idiopathic generalized epilepsies (IGEs) show a polygenic origin and may arise from dysfunction of various types of voltage-and ligandgated ion channels. There is an increasing body of literature implicating both high-and low-voltage-activated (HVA and LVA) calcium channels and their ancillary subunits in IGEs. Cav2.1 (P/Q-type) calcium channels control synaptic transmission at presynaptic nerve terminals, and mutations in the gene encoding the Cav2.1 α1 subunit (CACNA1A) have been linked to absence seizures in both humans and rodents. Similarly, mutations and loss of function mutations in ancillary HVA calcium channel subunits known to coassemble with Cav2.1 result in IGE phenotypes in mice. It is important to note that in all these mouse models with mutations in HVA subunits, there is a compensatory increase in thalamic LVA currents which likely leads to the seizure phenotype. In fact, gain-of-function mutations have been identified in Cav3.2 (an LVA or T-type calcium channel encoded by the CACNA1H gene) in patients with congenital forms of IGEs, consistent with increased excitability of neurons as a result of enhanced T-type channel function. In this paper, we provide a broad overview of the roles of voltage-gated calcium channels, their mutations, and how they might contribute to the river that terminates in epilepsy. © Springer-Verlag 2009.

Royer C.,Montpellier University | Winter R.,TU Dortmund
Current Opinion in Colloid and Interface Science | Year: 2011

Pressure effects on proteins stem from volumetric differences between their conformational states. These differences implicate rigid structure-based solvent excluded void volumes, although hydration and thermal expansivity differences between states may also play a role. Defining quantitatively the contributions of hydration and solvent excluded voids to protein volumetric properties and thermal expansivities remains a major challenge. Experimental information concerning thermal expansivity can be gained from pressure perturbation calorimetric studies (PPC). We review here recent results from PPC that suggest that while hydration plays a significant role in the volumetric properties of unfolded states of proteins, the volumetric properties of folded states are defined by structural and energetic properties of the folded chain. © 2011 Elsevier Ltd.

Zhu Q.-L.,Japan National Institute of Advanced Industrial Science and Technology | Zhong D.-C.,Japan National Institute of Advanced Industrial Science and Technology | Demirci U.B.,Montpellier University | Xu Q.,Japan National Institute of Advanced Industrial Science and Technology
ACS Catalysis | Year: 2014

A sodium-hydroxide-assisted reduction approach has been developed to control the synthesis of ultrafine surfactant-free bimetallic NiPt nanoparticles (NPs) supported on nanoporous carbon, Maxsorb MSC-30. For the first time, this catalyst exerts exceedingly high catalytic activity for 100% selective conversion of hydrazine borane (HB) to hydrogen at room temperature. This remarkably facile and effective reduction approach provides a powerful entry into ultrafine alloy NPs to make full use of noble metals and achieve enhanced performance, where the compositions of the alloy can be widely adjusted and tailored. Moreover, the catalytic results open up new avenues in the effective application of HB as a promising hydrogen storage material. (Chemical Equation Presented). © 2014 American Chemical Society.

Mainprice D.,Montpellier University | Hielscher R.,TU Chemnitz | Schaeben H.,TU Bergakademie Freiberg
Geological Society Special Publication | Year: 2011

This paper presents the background for the calculation of physical properties of an aggregate from constituent crystal properties and the texture of the aggregate in a coherent manner. Emphasis is placed on the important tensor properties of 2nd and 4th rank with applications in rock deformation, structural geology, geodynamics and geophysics. We cover texture information that comes from pole figure diffraction and single orientation measurements (electron backscattered diffraction or EBSD, electron channelling pattern, Laue pattern, optical microscope universal-stage). In particular, we provide explicit formulae for the calculation of the averaged tensor from individual orientations or from an orientation distribution function (ODF). For the latter we consider numerical integration and an approach based on the expansion into spherical harmonics. This paper also serves as a reference paper for the mathematical tensor capabilities of the texture analysis software MTEX, which is a comprehensive, freely available MatLab toolbox that covers a wide range of problems in quantitative texture analysis, for example, ODF modelling, pole figure to ODF inversion, EBSD data analysis and grain detection. MTEX offers a programming interface which allows the processing of involved research problems as well as highly customizable visualization capabilities; MTEX is therefore ideal for presentations, publications and teaching demonstrations. © The Geological Society of London 2011.

Heuret A.,Third University of Rome | Lallemand S.,Montpellier University | Funiciello F.,Third University of Rome | Piromallo C.,I.N.G.V. | Faccenna C.,Third University of Rome
Geochemistry, Geophysics, Geosystems | Year: 2011

Based on global earthquake catalogs, the hypocenters, nodal planes, and seismic moments of worldwide subduction plate interface earthquakes were extracted for the period between 1900 and 2007. Assuming that the seismogenic zone coincides with the distribution of 5.5 ≤ M < 7 earthquakes, the subduction interface seismogenic zones were mapped for 80% of the trench systems and characterized with geometrical and mechanical parameters. Using this database, correlations were isolated between significant parameters to identify cause-effect relationships. Empirical laws obtained in previous studies were revisited in light of this more complete, accurate, and uniform description of the subduction interface seismogenic zone. The seismogenic zone was usually found to end in a fore-arc mantle, rather than at a Moho depth. The subduction velocity was the first-order controlling parameter for variations in the physical characteristics of plate interfaces, determining both the geometry and mechanical behavior. As such, the fast subduction zones and cold slabs were associated with large and steep plate interfaces, which, in turn, had large seismic rates. The subduction velocity could not account for the potential earthquake magnitude diversity that was observed along the trenches. Events with Mw ≥ 8.5 preferentially occurred in the vicinity of slab edges, where the upper plate was continental and the back-arc strain was neutral. This observation was interpreted in terms of compressive normal stresses along the plate interface. Large lateral ruptures should be promoted in neutral subduction zones due to moderate compressive stresses along the plate interface that allow the rupture to propagate laterally. Copyright © 2011 by the American Geophysical Union.

Bellanger J.M.,Montpellier University
Journal of cell science | Year: 2012

Doublecortin-domain containing (DCDC) genes play key roles in the normal and pathological development of the human brain cortex. The origin of the cellular specialisation and the functional redundancy of these microtubule (MT)-associated proteins (MAPs), especially those of Doublecortin (DCX) and Doublecortin-like kinase (DCLKs) genes, is still unclear. The DCX domain has the ability to control MT architecture and bundling. However, the physiological significance of such properties is not fully understood. To address these issues, we sought post-mitotic roles for zyg-8, the sole representative of the DCX-DCLK subfamily of genes in C. elegans. Previously, zyg-8 has been shown to control anaphase-spindle positioning in one-cell stage embryos, but functions of the gene later in development have not been investigated. Here we show that wild-type zyg-8 is required beyond early embryonic divisions for proper development, spontaneous locomotion and touch sensitivity of adult worms. Consistently, we find zyg-8 expression in the six touch receptor neurons (TRNs), as well as in a subset of other neuronal and non-neuronal cells. In TRNs and motoneurons, zyg-8 controls cell body shape/polarity and process outgrowth and morphology. Ultrastructural analysis of mutant animals reveals that zyg-8 promotes structural integrity, length and number of individual MTs, as well as their bundled organisation in TRNs, with no impact on MT architecture.

Debrie J.,University Paris Est Creteil | Lavaud-Letilleul V.,Montpellier University | Parola F.,Parthenope University of Naples
Journal of Transport Geography | Year: 2013

The evolution of public-private relationships has driven many economic sectors to undergo de-centralisation and de-regulation. Throughout these transformations, an appreciation of governance is key to understanding the process. In recent years, seaports have undergone dramatic changes in governance as reported in academic and policy literature. The World Bank, for example, outlined a well-known taxonomy of major governance models. However, this literature does not capture of the specificities of local environments, or " embed" the changes in specific institutional and economic contexts. This paper analyses embeddedness in ports and their associated governance structures. We analyse and discuss (i) the complexity and the heterogeneity of the institutional framework, (ii) the multi-layered decisional chain, (iii) the geo-economic dimension, and (iv) the socio-cultural environment of reformed ports. The paper takes a dynamic view of port reform trajectories. We illustrate the theoretical discussion with a comparison of ports in France and Italy. We show the effects of local forces in shaping national port reform schemes, and we examine the relationship between global trends and embeddedness. © 2012 Elsevier Ltd.

Grimanelli D.,Montpellier University
Current Opinion in Plant Biology | Year: 2012

Apomictic plants reproduce asexually through seeds by avoiding both meiosis and fertilization. While apomixis is genetically controlled, individual loci contributing to its expression have yet to be identified. Here, we review recent results indicating that RNA-dependent DNA methylation pathways acting during female reproduction are essential for proper reproductive development in plants, and may represent key regulators of the differentiation between apomictic and sexual reproduction. © 2011 Elsevier Ltd.

Glemin S.,Montpellier University
Genetics | Year: 2011

Heterosis is a widespread phenomenon corresponding to the increase in fitness following crosses between individuals from different populations or lines relative to their parents. Its genetic basis has been a topic of controversy since the early 20th century. The masking of recessive deleterious mutations in hybrids likely explains a substantial part of heterosis. The dynamics and consequences of these mutations have thus been studied in depth. Recently, it was suggested that GC-biased gene conversion (gBGC) might strongly affect the fate of deleterious mutations and may have significant fitness consequences. gBGC is a recombination-associated process mimicking selection in favor of G and C alleles, which can interfere with selection, for instance by increasing the frequency of GC deleterious mutations. I investigated how gBGC could affect the amount and genetic structure of heterosis through an analysis of the interaction between gBGC and selection in subdivided populations. To do so, I analyzed the infinite island model both by numerical computations and by analytical approximations. I showed that gBGC might have little impact on the total amount of heterosis but could greatly affect its genetic basis. Copyright © 2011 by the Genetics Society of America.

Ferre S.,U.S. National Institutes of Health | Casado V.,University of Barcelona | Casado V.,Research Center Biomedica en Red sobre Enfermedades Neurodegenerativas | Devi L.A.,Mount Sinai School of Medicine | And 9 more authors.
Pharmacological Reviews | Year: 2014

Most evidence indicates that, as for family C G protein-coupled receptors (GPCRs), family A GPCRs form homo- and heteromers. Homodimers seem to be a predominant species, with potential dynamic formation of higher-order oligomers, particularly tetramers. Although monomeric GPCRs can activate G proteins, the pentameric structure constituted by one GPCR homodimer and one heterotrimeric G protein may provide a main functional unit, and oligomeric entities can be viewed as multiples of dimers. It still needs to be resolved if GPCR heteromers are preferentially heterodimers or if they are mostly constituted by heteromers of homodimers. Allosteric mechanisms determine a multiplicity of possible unique pharmacological properties of GPCR homomers and heteromers. Some general mechanisms seemto apply, particularly at the level of ligand-binding properties. In the frame of the dimer-cooperativity model, the two-state dimer model provides the most practical method to analyze ligand-GPCR interactions when considering receptor homomers. In addition to ligand-binding properties, unique properties for each GPCR oligomer emerge in relation to different intrinsic efficacy of ligands for different signaling pathways (functional selectivity). This gives a rationale for the use of GPCR oligomers, and particularly heteromers, as novel targets for drug development. Herein, we review the functional and pharmacological properties of GPCR oligomers and provide some guidelines for the application of discrete direct screening and highthroughput screening approaches to the discovery of receptor-heteromer selective compounds.

Gilleland E.,U.S. National Center for Atmospheric Research | Ribatet M.,Montpellier University | Stephenson A.G.,CSIRO
Extremes | Year: 2013

Extreme value methodology is being increasingly used by practitioners from a wide range of fields. The importance of accurately modeling extreme events has intensified, particularly in environmental science where such events can be seen as a barometer for climate change. These analyses require tools that must be simple to use, but must also implement complex statistical models and produce resulting inferences. This document presents a review of the software that is currently available to scientists for the statistical modeling of extreme events. We discuss all software known to the authors, both proprietary and open source, targeting different data types and application areas. It is our intention that this article will simplify the process of understanding the available software, and will help promote the methodology to an expansive set of scientific disciplines. © 2012 The Author(s).

Peeters M.,Montpellier University
Expert review of anti-infective therapy | Year: 2013

HIV-1 in humans resulted from at least four cross-species transmissions of simian immunodeficiency viruses (SIVs) from chimpanzees and gorillas in West Central Africa, while HIV-2 viruses resulted from at least eight independent transmissions of SIVs infecting sooty mangabeys in West Africa only, where one of these transmissions (HIV-1 group M) is responsible for the global epidemic. HIV-1 M is subdivided into nine subtypes and a wide diversity of circulating recombinant forms (CRFs) and unique recombinant forms. The heterogenic HIV-1 M subtype/CRF distribution is the result of founder effects. The genetic diversity of HIV-1 continues to increase overtime due to demographic factors such as travel and migration and frequent co/superinfections. In addition, the expanded access to antiretrovirals leads to an increasing number of drug-resistant strains, especially in resource limited countries.

Safar M.E.,University of Paris Descartes | Nilsson P.M.,Lund University | Blacher J.,University of Paris Descartes | Mimran A.,Montpellier University
Current Hypertension Reports | Year: 2012

Whereas larger arteries participate in the dampening of blood pressure (BP) oscillations resulting from intermittent ventricular ejection, smaller arteries steadily deliver an adequate supply of blood from the heart to the peripheral organs. Numerous active mechanisms are involved in this process. Cyclic stress acts differently from steady stress, inducing stronger and stiffer material of the vessel wall than under static conditions. Cyclic strain participates in the phenotypic plasticity of smooth muscle cells, initiates transduction mechanisms and induces the transcriptional profile of mechanically induced genes. Finally, the autoregulatory mechanism protecting the brain, heart and kidney from cardiovascular (CV) damage differ markedly according to their localization. Whereas the heart is dependent on pulsatile forces, owing to the diastolic perfusion of coronary arteries, the brain and the kidney are rather influenced by steady mechanical forces. For the kidney, the transmission of pulsatile pressure may greatly contribute to glomerular sclerosis in the elderly. © Springer Science+Business Media, LLC 2012.

Duffau H.,Montpellier University | Duffau H.,French Institute of Health and Medical Research | Mandonnet E.,Hopital Lariboisiere
Acta Neurochirurgica | Year: 2013

Diffuse low-grade glioma (DLGG) is a growing pre-cancerous tumor, often diagnosed in patients with no or only mild deficit. Maximal and early surgical resection is currently the first therapeutic option, in order to delay the malignant transformation and thus increase the overall survival. Preserving the quality of life (QoL) is nonetheless another priority. Here, our purpose is to weight the value of the extent of resection versus the neurological worsening that could be voluntarily generated by a radical resection; that is, to study the "onco-functional balance" at the individual level. To this end, we will examine DLGG involving the supplementary motor area and DLGG involving visual pathways. We will consider the benefit-risk ratio of different strategies of resection, according to the brain structures actually invaded and their plastic potential. The aim is to increase both the quantity of life and the time with a normal QoL, on the basis of strong interactions between the tumor course, brain reorganization and multistage surgical approach adapted to each patient over time. To this end, beyond the conceptual and technical issues, the most important point remains the honest and unique relationship between the surgical oncologist and the patient, based on clear and complete information about the behavior of DLGG versus the expected medical and social consequences of a resection over years. In other words, in the era of "evidence-based medicine", it is crucial to not forget "individual-based medicine" by offering tailored resections adapted to each patient. © 2013 Springer-Verlag Wien.

Weitz J.S.,Georgia Institute of Technology | Poisot T.,University of Quebec at Rimouski | Poisot T.,Quebec Center for Biodiversity science | Meyer J.R.,Michigan State University | And 5 more authors.
Trends in Microbiology | Year: 2013

Phage and their bacterial hosts are the most abundant and genetically diverse group of organisms on the planet. Given their dominance, it is no wonder that many recent studies have found that phage-bacteria interactions strongly influence global biogeochemical cycles, incidence of human diseases, productivity of industrial microbial commodities, and patterns of microbial genome diversity. Unfortunately, given the extreme diversity and complexity of microbial communities, traditional analyses fail to characterize interaction patterns and underlying processes. Here, we review emerging systems approaches that combine empirical data with rigorous theoretical analysis to study phage-bacterial interactions as networks rather than as coupled interactions in isolation. © 2012 Elsevier Ltd.

Lehmann L.,University of Lausanne | Rousset F.,Montpellier University
Biology and Philosophy | Year: 2014

Individual-as-maximizing agent analogies result in a simple understanding of the functioning of the biological world. Identifying the conditions under which individuals can be regarded as fitness maximizing agents is thus of considerable interest to biologists. Here, we compare different concepts of fitness maximization, and discuss within a single framework the relationship between Hamilton's (J Theor Biol 7:1-16, 1964) model of social interactions, Grafen's (J Evol Biol 20:1243-1254, 2007a) formal Darwinism project, and the idea of evolutionary stable strategies. We distinguish cases where phenotypic effects are additive separable or not, the latter not being covered by Grafen's analysis. In both cases it is possible to define a maximand, in the form of an objective function φ{symbol}(z), whose argument is the phenotype of an individual and whose derivative is proportional to Hamilton's inclusive fitness effect. However, this maximand can be identified with the expression for fecundity or fitness only in the case of additive separable phenotypic effects, making individual-as-maximizing agent analogies unattractive (although formally correct) under general situations of social interactions. We also feel that there is an inconsistency in Grafen's characterization of the solution of his maximization program by use of inclusive fitness arguments. His results are in conflict with those on evolutionary stable strategies obtained by applying inclusive fitness theory, and can be repaired only by changing the definition of the problem. © 2014 Springer Science+Business Media Dordrecht.

Poli J.,French National Center for Scientific Research | Tsaponina O.,Umea University | Crabbe L.,French National Center for Scientific Research | Crabbe L.,Salk Institute for Biological Studies | And 5 more authors.
EMBO Journal | Year: 2012

Intracellular deoxyribonucleoside triphosphate (dNTP) pools must be tightly regulated to preserve genome integrity. Indeed, alterations in dNTP pools are associated with increased mutagenesis, genomic instability and tumourigenesis. However, the mechanisms by which altered or imbalanced dNTP pools affect DNA synthesis remain poorly understood. Here, we show that changes in intracellular dNTP levels affect replication dynamics in budding yeast in different ways. Upregulation of the activity of ribonucleotide reductase (RNR) increases elongation, indicating that dNTP pools are limiting for normal DNA replication. In contrast, inhibition of RNR activity with hydroxyurea (HU) induces a sharp transition to a slow-replication mode within minutes after S-phase entry. Upregulation of RNR activity delays this transition and modulates both fork speed and origin usage under replication stress. Interestingly, we also observed that chromosomal instability (CIN) mutants have increased dNTP pools and show enhanced DNA synthesis in the presence of HU. Since upregulation of RNR promotes fork progression in the presence of DNA lesions, we propose that CIN mutants adapt to chronic replication stress by upregulating dNTP pools. © 2012 European Molecular Biology Organization | All Rights Reserved.

Burks A.W.,University of North Carolina at Chapel Hill | Calderon M.A.,Imperial College London | Casale T.,Creighton University | Cox L.,Nova Southeastern University | And 4 more authors.
Journal of Allergy and Clinical Immunology | Year: 2013

Allergy immunotherapy (AIT) is an effective treatment for allergic asthma and rhinitis, as well as venom-induced anaphylaxis. In addition to reducing symptoms, AIT can change the course of allergic disease and induce allergen-specific immune tolerance. In current clinical practice immunotherapy is delivered either subcutaneously or sublingually; some allergens, such as grass pollen, can be delivered through either route, whereas others, such as venoms, are only delivered subcutaneously. Both subcutaneous and sublingual immunotherapy appear to have a duration of efficacy of up to 12 years, and both can prevent the development of asthma and new allergen sensitivities. In spite of the advances with AIT, safer and more effective AIT strategies are needed, especially for patients with asthma, atopic dermatitis, or food allergy. Novel approaches to improve AIT include use of adjuvants or recombinant allergens and alternate routes of administration. As part of the PRACTALL initiatives, the European Academy of Allergy and Clinical Immunology and the American Academy of Allergy, Asthma & Immunology nominated an expert team to develop a comprehensive consensus report on the mechanisms of AIT and its use in clinical practice, as well as unmet needs and ongoing developments in AIT. This resulting report is endorsed by both academies. © 2012 American Academy of Allergy, Asthma & Immunology.

Bierne N.,Montpellier University | Bierne N.,French National Center for Scientific Research
Evolution | Year: 2010

Loci with higher levels of population differentiation than the neutral expectation are traditionally interpreted as evidence of ongoing selection that varies in space. This article emphasizes an alternative explanation that has been largely overlooked to date: in species subdivided into large subpopulations, enhanced differentiation can also be the signature left by the fixation of an unconditionally favorable mutation on its chromosomal neighborhood. This is because the hitchhiking effect is expected to diminish as the favorable mutation spreads from the deme in which it originated to other demes. To discriminate among the two alternative scenarios one needs to investigate how genetic structure varies along the chromosomal region of the locus. Local hitchhiking is shown to generate a single sharp peak of differentiation centered on the adaptive polymorphism and the standard signature of a selective sweep only in those subpopulations in which the allele is favored. Global hitchhiking produces two domes of differentiation on either side of the fixed advantageous mutation and signatures of a selective sweep in every subpopulation, albeit of different magnitude. Investigating population differentiation around a locus that strongly differentiates two otherwise genetically similar populations of the marine mussel Mytilus edulis, plausible evidence for the global hitchhiking hypothesis has been obtained. Global hitchhiking is a neglected phenomenon that might prove to be important in species with large population sizes such as many marine invertebrates. © 2010 The Author(s). Evolution © 2010 The Society for the Study of Evolution.

Ajili M.,CNRS Condensed Matter Physics Laboratory | Castagne M.,Montpellier University | Turki N.K.,CNRS Condensed Matter Physics Laboratory
Superlattices and Microstructures | Year: 2013

Tin doped zinc oxide (ZnO:Sn) thin films were deposited onto Pyrex glass substrates by chemical spray pyrolysis technique starting from zinc acetate (CH3CO2)2Znṡ2H2O and tin chloride SnCl2. The effect of Sn doping on structural, optical and electrical properties was investigated. The atomic percentages of dopant in ZnO-based solution were y = [Sn4+]/[Zn2+] = 0%, 0.2%, 0.6% and 1%. It was found that all the thin films have a preferential c-axis orientation. With increase of Sn doping, the peak position of the (0 0 2) plane was shifted to the high 2θ values. ZnO:Sn demonstrated obviously improved surface roughness, reduced average crystallite size, enhanced Hall mobility and reduced resistivity. Among all of the tin doped zinc oxide in this study, films doped with 0.6 at.% Sn concentration exhibited the best properties, namely a Hall mobility of 9.22 cm2 V-1 s-1, an RMS roughness of 37.15 nm and a resistivity of 8.32 × 10-2 cm.

Martin G.,Montpellier University | Martin G.,IRD Montpellier | Gandon S.,CNRS Center of Evolutionary and Functional Ecology
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2010

The lethal mutagenesis hypothesis states that within-host populations of pathogens can be driven to extinction when the load of deleterious mutations is artificially increased with a mutagen, and becomes too high for the population to be maintained. Although chemical mutagens have been shown to lead to important reductions in viral titres for a wide variety of RNA viruses, the theoretical underpinnings of this process are still not clearly established. A few recent models sought to describe lethal mutagenesis but they often relied on restrictive assumptions. We extend this earlier work in two novel directions. First, we derive the dynamics of the genetic load in a multivariate Gaussian fitness landscape akin to classical quantitative genetics models. This fitness landscape yields a continuous distribution of mutation effects on fitness, ranging from deleterious to beneficial (i.e. compensatory) mutations. We also include an additional class of lethal mutations. Second, we couple this evolutionary model with an epidemiological model accounting for the within-host dynamics of the pathogen. We derive the epidemiological and evolutionary equilibrium of the system. At this equilibrium, the density of the pathogen is expected to decrease linearly with the genomic mutation rate U. We also provide a simple expression for the critical mutation rate leading to extinction. Stochastic simulations show that these predictions are accurate for a broad range of parameter values. As they depend on a small set of measurable epidemiological and evolutionary parameters, we used available information on several viruses to make quantitative and testable predictions on critical mutation rates. In the light of this model, we discuss the feasibility of lethal mutagenesis as an efficient therapeutic strategy. © 2010 The Royal Society.

Fellous S.,Cornell University | Fellous S.,Montpellier University | Lazzaro B.P.,Cornell University
Molecular Ecology | Year: 2011

Almost all studies of the immune system of animals with metamorphosis have focused on either larval or on adult immunity, implicitly assuming that these traits are either perfectly correlated or evolutionarily independent. In this study, we use 80 crosses among 21 Drosophila melanogaster lines to investigate the degree and constancy of genetic correlation in immune system activity between larvae and adults. The constitutive transcription of Diptericin, a gene encoding a defensive antimicrobial peptide, was controlled by the same genetic factors in larvae and adults, with variation in expression determined exclusively by nonadditive genetic effects. This contrasted with another peptide-encoding gene, Drosomycin, in which larval transcription was highly variable and determined by additive effects but adult transcription genetically invariant. We found no evidence for a fitness cost to the transcription of these genes in our study. The shared genetic control of larval and adult Diptericin transcription stands in contrast to predictions of the adaptive decoupling hypothesis, which states that distinct life-stages should permit the independent evolution of larval and adult phenotypes. Importantly, genetic correlations between larval and adult immunities imply that parasite pressure on one life-stage can drive the evolution of immunity (and resistance) in the other life-stage. © 2011 Blackwell Publishing Ltd.

Kazan M.,University of Technology of Troyes | Bruyant A.,University of Technology of Troyes | Royer P.,University of Technology of Troyes | Masri P.,Montpellier University
Surface Science Reports | Year: 2010

This review is intended to provide a critical and up-to-date survey of the analytical approximation methods that are encountered in interface thermal conductance. Because of the importance of the III-nitride materials for novel technological applications, these methods are applied to the thermal conductance of the interfaces between the III-nitride thin films and their commonly used substrates. The phonon behavior and the probability that a phonon transmits from the III-nitride film to the substrate are described first within the context of two limiting models for the interface thermal conductance. The acoustic mismatch model, which assumes that all the phonons incident to the interface are specularly transmitted or specularly reflected, and the diffuse mismatch model, which assumes that all the phonons incident to the interface are diffusively transmitted or diffusively reflected. We show that these two limiting models give very different results for the thermal conductance of the interface between the III-nitride films and their substrates. Next, a statistical model which describes the reflection of plane waves from rough surface is employed to discriminate between the specularly transmitted phonons and the diffusively transmitted phonons. This model predicts that a reflected plane wave leads to a plane wave in the direction of specular reflection and to a contribution with a finite angular spread about that direction depending on the tangential correlation of the surface asperities. Based upon this result, a new model for the interface thermal conductance, that interpolates between the acoustic mismatch model and the diffuse mismatch model and takes into account, instead the Debye approximation, the detailed phonon spectra of the materials in contact, is developed and applied to the interfaces GaN/Si, GaN/SiC, AlN/Si, AlN/SiC, InN/Si, and InN/SiC. In addition to the phonon wavevector, or alternatively, the phonon energy and the angles of incidence, the probability of the specular transmission and the probability of the diffuse transmissions are taken to depend on the interface roughness and the tangential correlation of the interface asperities. Generally speaking, for the case of interface with zero tangential correlation the interface thermal conductance increases with increasing the interface roughness, whereas for an interface with infinite tangential correlation the interface thermal conductance depends on the mismatch between the phonon densities of states of the materials in contact. © 2010 Elsevier B.V. All rights reserved.

Mouillot D.,Montpellier University | Villeger S.,CNRS Biological Evolution and Diversity Laboratory | Scherer-Lorenzen M.,Albert Ludwigs University of Freiburg | Mason N.W.H.,Landcare Research
PLoS ONE | Year: 2011

The accelerating rate of change in biodiversity patterns, mediated by ever increasing human pressures and global warming, demands a better understanding of the relationship between the structure of biological communities and ecosystem functioning (BEF). Recent investigations suggest that the functional structure of communities, i.e. the composition and diversity of functional traits, is the main driver of ecological processes. However, the predictive power of BEF research is still low, the integration of all components of functional community structure as predictors is still lacking, and the multifunctionality of ecosystems (i.e. rates of multiple processes) must be considered. Here, using a multiple-processes framework from grassland biodiversity experiments, we show that functional identity of species and functional divergence among species, rather than species diversity per se, together promote the level of ecosystem multifunctionality with a predictive power of 80%. Our results suggest that primary productivity and decomposition rates, two key ecosystem processes upon which the global carbon cycle depends, are primarily sustained by specialist species, i.e. those that hold specialized combinations of traits and perform particular functions. Contrary to studies focusing on single ecosystem functions and considering species richness as the sole measure of biodiversity, we found a linear and non-saturating effect of the functional structure of communities on ecosystem multifunctionality. Thus, sustaining multiple ecological processes would require focusing on trait dominance and on the degree of community specialization, even in species-rich assemblages. © 2011 Mouillot et al.

Olivi-Tran N.,Montpellier University
Advanced Studies in Theoretical Physics | Year: 2010

It has been shown in two previous articles by Olivi-Tran and Gauthier [1] and by Olivi-Tran [2] that our three dimensional universe may be embedded in a four-dimensional space. The radius of curvature of our universe is related to this fourth dimension and to time. Here we show with these assumptions, that a possible candidate for the Higgs scalar field has a potential which is a four dimensional box with two temporal boundaries 0 and T. This scalar field gives a mass to massless particles. This mass is quantized by Planck's constant and is proportional to the duration (i.e. to T) of an interaction which could have create the particle with mass from a massless particle.

Quere I.,Montpellier University
Journal of vascular surgery | Year: 2012

A current debate concerning suspected superficial vein thrombosis (SVT) focuses on the need of performing a compression ultrasound (CUS) exploration for confirming the diagnosis of SVT. This study was conducted to determine the clinical relevance and optimal CUS exploration in patients with symptomatic SVT. We analyzed the characteristics of SVT and concomitant deep vein thrombosis (DVT) in patients included in the Prospective Observational Superficial Thrombophlebitis (POST) multicenter, observational prospective study. All patients underwent complete bilateral lower limb CUS, exploring both the superficial and deep venous systems. A total of 844 patients with clinical symptoms of SVT were recruited, of which 99 isolated SVTs (21.4%) had saphenofemoral/popliteal junction involvement, and 198 (23.5%) had a concomitant DVT, with 41.8% of them proximal DVTs. In 83 patients (41.9%), DVT and SVT were not contiguous. Five of 639 patients (1%) had an isolated contralateral DVT (ie, not bilateral). Age ≥ 75 years (odds ratio [OR], 2.3; 95% confidence interval [CI], 1.6-3.4), inpatient status (OR, 5.4; 95% CI, 3.4-8.7), a personal history of DVT or pulmonary embolism (OR, 1.8; 95% CI, 1.2-2.8), and SVT on nonvaricose veins (OR, 3.3; 95% CI, 2.1-5.0) were significantly and independently associated with an increased risk of concomitant DVT. Half of the patients exhibited none of these risk factors, and the prevalence of concomitant DVT dropped to 11%. In patients with symptomatic SVT, a CUS exploration screening the whole venous system of the affected limb is useful because it provides information that has important consequences for the management of these patients. Copyright © 2012 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

Vitale Brovarone A.,CNRS Institute of Mineralogy, Materials Physics and Cosmochemistry | Alard O.,Montpellier University | Beyssac O.,CNRS Institute of Mineralogy, Materials Physics and Cosmochemistry | Martin L.,University of Western Australia | Picatto M.,University of Turin
Journal of Metamorphic Geology | Year: 2014

Although lawsonite-bearing rocks are rare in exhumed high-pressure (HP) terranes, they are considered to exert a primary role in subduction dynamics. Recent observations in natural settings have shown that fluid-rock interaction at HP conditions, including metasomatism, may lead to unusually high lawsonite amounts even in rocks that originally contained little or no lawsonite. This process may therefore bear important implications for element recycling in subduction zones. A detailed characterization of the geochemical fingerprints associated with lawsonite metasomatism is presented in this contribution. The studied rocks belong to the HP terranes of Alpine Corsica (France), which is the largest documented exposure for lawsonite metasomatism. Metasomatic lawsonite displays complex compositional zoning, including high trace element, Cr and Ti content. The trace element content is much higher compared with the average of non-metasomatic lawsonite, and is in line with the re-incorporation of large amounts of trace elements (e.g. REE, Sr, Pb, Th) in the rock during metasomatism, as shown by mass transfer calculations. Our data suggest that serpentinites represented the main fluid source for the metasomatism, with concurrent contribution of other, possibly Ca-rich lithologies, such as mafic or meta-sedimentary rocks. We propose that the breakdown of metasomatic lawsonite may contribute to the genesis of magmas and their characteristic geochemical signatures. © 2014 John Wiley & Sons Ltd.

Padron-Navarta J.A.,Australian National University | Padron-Navarta J.A.,Montpellier University | Hermann J.,Australian National University | O'Neill H.S.C.,Australian National University
Earth and Planetary Science Letters | Year: 2014

Synthetic hydroxylated titanium-bearing and undoped MgO-buffered forsterite crystals were heated at atmospheric pressure in air at temperatures from 800 to 1200°C to determine hydrogen diffusion as a function of the type of point-defect mechanism by which the hydroxyl is incorporated. OH-stretching bands, measured by infrared spectroscopy, were assigned to the four substitution mechanisms: Ti-clinohumite point defects, silicon and magnesium vacancies, and point defects associated with trivalent cations. In the experiments at 800 to 1000°C, hydrous defects related to trivalent cations and Mg-vacancies disappear first in the Ti-doped forsterite, followed by the hydrous defects related to Ti and a fraction of the hydrated Si-vacancies. Measured bulk diffusion coefficients for hydrogen exchange related to the latter process are one order of magnitude slower than previously reported and with higher activation energy (296 ± 14kJmol -1). After the elimination of the defects related to Ti, the hydroxyl concentration related to Si-vacancies remained constant for the duration of the experiments. This observation is in agreement with the very slow diffusivity of hydrogen in Si-vacancies measured in the undoped MgO-buffered dehydroxylation experiments at higher temperatures (from 1000 to 1200°C), which were ~3 orders of magnitude slower than previously reported at 1000°C, and with an activation energy of 461 ± 11kJmol -1. Hydrogen diffusion in forsterite is far more complex than previously assumed. This complexity can be used to gain more information on the timescales of the processes causing olivine to lose its structural "water", but quantitative modeling will require not only the knowledge of the intrinsic diffusivities of the different hydrous defects but also their relative proportions and the possible reactions between them. © 2014 Elsevier B.V.

Hugnot J.P.,French Institute of Health and Medical Research | Hugnot J.P.,Montpellier University | Franzen R.,University of Liege
Frontiers in Bioscience | Year: 2011

In the brain, specific signalling pathways localized in highly organized regions called niches, allow the persistence of a pool of stem and progenitor cells that generate new neurons and glial cells in adulthood. Much less is known on the spinal cord central canal niche where a sustained adult neurogenesis is not observed. Here we review our current knowledge of this caudal niche in normal and pathological situations. Far from being a simple layer of homogenous cells, this region is composed of several cell types localized at specific locations, expressing characteristic markers and with different morphologies and functions. We further report on a screen of online geneexpression databases to better define this spinal cord niche. Several genes were found to be preferentially expressed within or around the central canal region (Bmp6, CXCR4, Gdf10, Fzd3, Mdk, Nrtn, Rbp1, Shh, Sox4, Wnt7a) some of which by specific cellular subtypes. In depth characterization of the spinal cord niche constitutes a framework to make the most out of this endogenous cell pool in spinal cord disorders.

Plantard G.,CNRS PROMES | Janin T.,CNRS PROMES | Janin T.,Societe Resolution Espace Entreprises Mediterranee | Goetz V.,CNRS PROMES | Brosillon S.,Montpellier University
Applied Catalysis B: Environmental | Year: 2012

In the field of advanced oxidization processes based on solar radiation, heterogeneous solar catalysis involves exciting a photocatalyst with UV rays and one of the major problem encountered is optimizing the use of the sunlight. Catalysts in suspension develop the best ability to degrade polluting molecules. In this study, two TiO 2 catalysts in suspension which develop the best ability to degrade polluting molecules, with a granulometric ratio of 1000, have been investigated. All the experiments were performed under natural sunlight in a photoreactor consisting of three identical but independent reactors. A simple kinetic model of degradation is purposed for the media each in its optimal configuration, considering the irradiation, the catalyst and pollutant concentrations. First of all, we show that the kinetics of degradation decline as a function of the quantity of photons used and that the two catalysts (with a granulometric ratio of 1000), achieved similar performances when they were used in their optimal configurations. Secondly, the logarithm of the concentration of pyrimethanil decreased linearly as a function of the combination QUVCTiO2m. This indicates the direct dependence of the quantity degraded on the quantity of UV energy effectively available for the photocatalytic reaction. © 2011 Elsevier B.V.

Demoly P.,Montpellier University | Hagedoorn P.,University of Groningen | De Boer A.H.,University of Groningen | Frijlink H.W.,University of Groningen
Respiratory Medicine | Year: 2014

Background Although understanding of the scientific basis of aerosol therapy with dry powder inhalers (DPIs) has increased, some misconceptions still persist. These include the beliefs that high resistance inhalers are unsuitable for some patients, that extra fine (<1.0 μm) particles improve peripheral lung deposition and that inhalers with flow rate-independent fine particle fractions (FPFs) produce a more consistent delivered dose to the lungs. Objectives This article aims to clarify the complex inter-relationships between inhaler design and resistance, inspiratory flow rate (IFR), FPF, lung deposition and clinical outcomes, as a better understanding may result in a better choice of DPI for individual patients. Methods The various factors that determine the delivery of drug particles into the lungs are reviewed. These include aerodynamic particle size distribution, the inspiratory manoeuvre, airway geometry and the three basic principles that determine the site and extent of deposition: inertial impaction, sedimentation and diffusion. DPIs are classed as either dependent or independent of inspiratory flow rate and vary in their internal resistance to inspiration. The effects of these characteristics on drug deposition in the airways are described using data from studies directly comparing currently available inhaler devices. Results Clinical experience shows that most patients can use a high resistance DPI effectively, even during exacerbations. Particles in the aerodynamic size range from 1.5-5 μm are shown to be optimal, as particles <1.0 μm are very likely to be exhaled again while those >5 μm may impact on the oropharynx. For DPIs with a constant FPF at all flow rates, less of the delivered dose reaches the central and peripheral lung when the flow rate increases, risking under-dosing of the required medication. In contrast, flow rate-dependent inhalers increase their FPF output at higher flow rates, which compensates for the greater impaction on the upper airways as flow rate increases. Conclusions The technical characteristics of different inhalers and the delivery and deposition of the fine particle dose to the lungs may be important additional considerations to help the physician to select the most appropriate device for the individual patient to optimise their treatment. © 2014 Published by Elsevier Ltd.

Lanfear R.,Australian National University | Welch J.J.,Montpellier University | Bromham L.,Australian National University
Trends in Ecology and Evolution | Year: 2010

Evidence is accumulating that rates of molecular evolution vary substantially between species, and that this rate variation is partly determined by species characteristics. A better understanding of how and why rates of molecular evolution vary provides a window on evolutionary processes, and might facilitate improvements in DNA sequence analysis. Measuring rates of molecular evolution and identifying the correlates of rate variation present a unique set of challenges. We describe and compare recent methodological advances that have been proposed to deal with these challenges. We provide a guide to the theoretical basis and practical application of the methods, outline the types of data on which they can be used, and indicate the types of questions they can be used to ask. © 2010 Elsevier Ltd.

Georgess D.,CNRS Lyon Institute of Functional Genomics | Machuca-Gayet I.,CNRS Lyon Institute of Functional Genomics | Blangy A.,Montpellier University | Jurdic P.,CNRS Lyon Institute of Functional Genomics
Cell Adhesion and Migration | Year: 2014

Osteoclasts are the cells responsible for physiological bone resorption. A specific organization of their most prominent cytoskeletal structures, podosomes, is crucial for the degradation of mineralized bone matrix. Each podosome is constituted of an F-actin-enriched central core surrounded by a loose F-actin network, called the podosome cloud. In addition to intrinsic actin dynamics, podosomes are defined by their adhesion to the extracellular matrix, mainly via core-linking CD44 and cloud-linking integrins. These properties allow podosomes to collectively evolve into different patterns implicated in migration and bone resorption. Indeed, to resorb bone, osteoclasts polarize, actively secrete protons, and proteases into the resorption pit where these molecules are confined by a podosome-containing sealing zone. Here, we review recent advancements on podosome structure and regulatory pathways in osteoclasts. We also discuss the distinct functions of different podosome patterns during the lifespan of a single osteoclast. © 2014 Landes Bioscience.

We use a triangular representation of the plunges of P, B, and T axes to compare the different ways tectonic regime is inferred from earthquake focal mechanisms in recent works. We argue that P, B, and T axes provide a reasonable estimate of principal stress directions when faulting is close to Andersonian conditions, and that this can be estimated from the location on a triangular diagram. We analyze the geometrical relationship between the plunges of P, B, and T axes on one hand, and the rake of slip and dip of nodal planes on the other hand. We show that the rake and dip level curves correspond to trajectories of the vertical direction along great and small circles with respect to the frame of the P, B, and T axes. This shows that dip-slip faulting is compatible with vertical P or T axes, but does not require it, and instead requires horizontal B axes. It also shows that strike-slip faulting does not require vertical B axes, but P and T axes with equal plunges. This also reveals that focal mechanisms where P, B, and T axes all have moderate plunge correspond to two very different types of nodal planes: a steeply dipping one with oblique slip and a moderately dipping one with strike-slip. Seismically active and moderately dipping strike-slip faults are to be found among these events. © 2009 Elsevier B.V. All rights reserved.

Demouchy S.,Montpellier University
Earth and Planetary Science Letters | Year: 2010

Nominally anhydrous minerals (NAMs) of Earth's mantle can contain hydrogen as atomic impurity in their crystal structures. This hydrogen substantially modifies many physical properties of Earth's mantle rocks. Also, the Earth's deep interior is made of rocks where minerals are separated by nanometer-scale interfaces call grain boundaries and interphase boundaries. These grain boundaries should carefully be considered as a potential hydrogen reservoir as well. I report here an experimental investigation of hydrogen diffusion through grain boundaries in olivine polycrystalline aggregates. Hot-press and diffusion experiments were performed using a gas-medium high-pressure vessel at a confining pressure of 300MPa, over a temperature range of 1000-1200°C. The diffusion assembly consisted of a dense polycrystalline cylinder of natural olivine from San Carlos (Arizona) mixed with olivine singles crystals of millimeter size. This mixture was couple with a talc cylinder. Ni capsule were used to buffer the oxygen fugacity at Ni-NiO level. Experiment durations varied from 3min to 4h. The presence of hydrogen in the sample was quantified using Fourier transform infrared spectroscopy. The calculation of the diffusion coefficients was based on the estimation of the length of polycrystalline solid affected by the diffusion of hydrogen. The absence or presence of hydrogen was recorded by the large olivines behaving here as "hydrogen sensor", which are implanted in the aggregate. The results indicate that effective hydrogen diffusivity which includes grain boundaries effect in olivine aggregate is barely one order of magnitude faster than hydrogen diffusion in an olivine single crystal with a diffusivity ~8.5×10-10m2s-1 at 1000°C and only twice faster ~2.1×10-9m2s-1 at 1200°C. Calculations of the diffusion data in relation to the Arrhenius Law, yield an activation energy of ~70±10kJmol-1. From these effective diffusivities and combined with published diffusion data for olivine single crystals, hydrogen diffusion in grain boundaries is extracted and yield diffusivities almost three order of magnitude faster (~5×10-6m2s-1 at 1200°C) than in an olivine single crystal at the equivalent high temperature. On geological scales and for coarse-grain rocks, hydrogen diffusivity in grain boundaries is not fast enough to compete with lattice diffusion. The relative large grain size of mantle rocks will ensure a very limited hydrogen transport by effective diffusion, and a good conservation of water-rich zones in the Earth's mantle. © 2010 Elsevier B.V.

Ellwanger U.,University Paris - Sud | Hugonie C.,Montpellier University
Advances in High Energy Physics | Year: 2012

We study the NMSSM with universal Susy breaking terms (besides the Higgs sector) at the GUT scale. Within this constrained parameter space, it is not difficult to find a Higgs boson with a mass of about 125 GeV and an enhanced cross-section in the diphoton channel. An additional lighter Higgs boson with reduced couplings and a mass ≲ 123 GeV is potentially observable at the LHC. The NMSSM-specific Yukawa couplings λ and κ are relatively large and tan β is small, such that λ, κ, and the top Yukawa coupling are of (1) at the GUT scale. The lightest stop can be as light as 105 GeV, and the fine-tuning is modest. WMAP constraints can be satisfied by a dominantly Higgsino-like LSP with substantial bino, wino, and singlino admixtures and a mass of 6090 GeV, which would potentially be detectable by XENON100. © 2012 Ulrich Ellwanger and Cyril Hugonie.

Martiniere A.,Oxford Brookes University | Gayral P.,Montpellier University | Hawes C.,Oxford Brookes University | Runions J.,Oxford Brookes University
Plant Journal | Year: 2011

Actin microfilament (MF) organization and remodelling is critical to cell function. The formin family of actin binding proteins are involved in nucleating MFs in Arabidopsis thaliana. They all contain formin homology domains in the intracellular, C-terminal half of the protein that interacts with MFs. Formins in class I are usually targeted to the plasma membrane and this is true of Formin1 (AtFH1) of A. thaliana. In this study, we have investigated the extracellular domain of AtFH1 and we demonstrate that AtFH1 forms a bridge from the actin cytoskeleton, across the plasma membrane and is anchored within the cell wall. AtFH1 has a large, extracellular domain that is maintained by purifying selection and that contains four conserved regions, one of which is responsible for immobilising the protein. Protein anchoring within the cell wall is reduced in constructs that express truncations of the extracellular domain and in experiments in protoplasts without primary cell walls. The 18 amino acid proline-rich extracellular domain that is responsible for AtFH1 anchoring has homology with cell-wall extensins. We also have shown that anchoring of AtFH1 in the cell wall promotes actin bundling within the cell and that overexpression of AtFH1 has an inhibitory effect on organelle actin-dependant dynamics. Thus, the AtFH1 bridge provides stable anchor points for the actin cytoskeleton and is probably a crucial component of the signalling response and actin-remodelling mechanisms. © 2011 Blackwell Publishing Ltd.

Girard O.,Research and Education Center | Micallef J.-P.,Montpellier University | Millet G.P.,University of Lausanne
European Journal of Applied Physiology | Year: 2011

This study investigated fatigue-induced changes in spring-mass model characteristics during repeated running sprints. Sixteen active subjects performed 12 × 40 m sprints interspersed with 30 s of passive recovery. Vertical and anterior-posterior ground reaction forces were measured at 5-10 m and 30-35 m and used to determine spring-mass model characteristics. Contact (P < 0.001), flight (P < 0.05) and swing times (P < 0.001) together with braking, push-off and total stride durations (P < 0.001) lengthened across repetitions. Stride frequency (P < 0.001) and push-off forces (P < 0.05) decreased with fatigue, whereas stride length (P = 0.06), braking (P = 0.08) and peak vertical forces (P = 0.17) changes approached significance. Center of mass vertical displacement (P < 0.001) but not leg compression (P > 0.05) increased with time. As a result, vertical stiffness decreased (P < 0.001) from the first to the last repetition, whereas leg stiffness changes across sprint trials were not significant (P > 0.05). Changes in vertical stiffness were correlated (r > 0.7; P < 0.001) with changes in stride frequency. When compared to 5-10 m, most of ground reaction force-related parameters were higher (P < 0.05) at 30-35 m, whereas contact time, stride frequency, vertical and leg stiffness were lower (P < 0.05). Vertical stiffness deteriorates when 40 m run-based sprints are repeated, which alters impact parameters. Maintaining faster stride frequencies through retaining higher vertical stiffness is a prerequisite to improve performance during repeated sprinting. © 2010 Springer-Verlag.

Baselga A.,University of Santiago de Compostela | Leprieur F.,Montpellier University
Methods in Ecology and Evolution | Year: 2015

Two alternative frameworks have been proposed to partition compositional dissimilarity into replacement and nestedness-resultant component or into replacement and richness-difference components. These are, respectively, the BAS (Baselga 2010, Global Ecology and Biogeography, 19, 134-143) and POD (Podani & Schmera . Oikos, 120, 1625-1638) frameworks. We conduct a systematic comparison of parallel components in alternative approaches. We test whether the replacement components derived from the BAS and POD frameworks are independent of richness difference. We also evaluate whether previously reported tests of monotonicity between indices and ecological processes are informative to assess the performance of indices. Finally, we illustrate the consequences of differences between the BAS and POD frameworks using the North American freshwater fish fauna as an empirical example. In the BAS framework, the nestedness-resultant component (βjne or βsne) accounts only for richness differences derived from nested patterns while, in the POD framework, richness-difference dissimilarity (βrich or βrich.s) accounts for all kind of richness differences. Likewise, the replacement components of both alternative methods account for different concepts. Only the replacement component of the BAS framework (βjtu or βsim) is independent of richness difference, while the parallel component in the POD framework (β-3 or β-3.s) is not (i.e. it is mathematically constrained by richness difference). Therefore, only the BAS framework allows separating (i) the variation in species composition derived from species replacement which is independent of richness difference (i.e. not mathematically constrained by it) and (ii) the variation in species composition derived from nested patterns. © 2015 British Ecological Society.

The elderly population in France has continued to increase. Aging and chronic diseases render this population vulnerable. Falls are a risk factor of becoming dependent because of their potentially severe consequences; the cost of care of the consequences is high. Hence, it is important to effectively prevent them. In this paper we will attempt to determine current practices and opinions in the Hautes-Pyrenees that is a department (Midi-Pyrenees region) in southwestern France, in order to analyze compliance with respect to the new recommendations of the Group for Research and Information on Osteoporosis (GRIO). The rules and procedures are based on the recommendations of the GRIO 2011. This evaluation examines the program through a survey of the general practitioners involved in its implementation in the Hautes-Pyrenees. Fifty-nine percent of GPs reported having more than 15% of patients aged over 65. They prescribe a systematic determination of vitamin D in 61% of cases and therapeutic in only 39% of cases. When there is an indication, it is one of the following situations: insufficient sun exposure (25%), repeated falls (22%), established osteoporosis (29%) or in the case of inducing osteoporosis treatment (24%). Supplementation is more often with vitamin D3 (50%) than vitamin D2 (14%), and it is the pattern of spaced doses that is most often applied. It is clear from this survey that in 61% of cases the dosages of vitamin D required by GPs in the Hautes-Pyrenees are not in accordance with the recommendations of the national health authorities. © 2014 Elsevier Masson SAS.

The site of Romain-la-Roche is a reference for the biochronology of Quaternary caballine equids. Its remains are described and compared with those of main types of the Western Europe large horses from Middle and beginning Late Pleistocene. An assignment to Equus achenheimensis is supported by dental and skeletal biometric features. This horse, who is assumed in other sites from the late Middle Pleistocene, could characterise the MNQ24 zone.

Blanchet S.,Ecole Polytechnique Federale de Lausanne | Lavalle J.,Montpellier University
Journal of Cosmology and Astroparticle Physics | Year: 2012

We make a detailed analysis of the indirect diffuse gamma-ray signals from dark matter annihilation in the Galaxy. We include the prompt emission, as well as the emission from inverse Compton scattering whenever the annihilation products contain light leptons. We consider both the contribution from the smooth dark matter halo and that from substructures. The main parameters for the latter are the mass function index and the minimal subhalo mass. We use recent results from N-body simulations to set the most reasonable range of parameters, and find that the signal can be boosted by a factor ranging from 2 to 15 towards the Galactic poles, slightly more towards the Galactic anticenter, with an important dependence on the subhalo mass index. This uncertainty is however much less than that of the extragalactic signal studied in the literature. We derive upper bounds on the dark matter annihilation cross section using the isotropic gamma-ray emission measured by Fermi-LAT, for two directions in the sky, the Galactic anticenter and the Galactic pole(s). The former represents the lowest irreducible signal from dark matter annihilation, and the latter is robust as the astrophysical background, dominated by the hadronic contribution, is rather well established in that direction. Finally, we show how the knowledge of the minimal subhalo mass, which formally depends on the dark matter particle interactions with normal matter, can be used to derive the mass function index. © 2012 IOP Publishing Ltd and Sissa Medialab srl.

Thery-Parisot I.,French National Center for Scientific Research | Chabal L.,Montpellier University | Chrzavzez J.,French National Center for Scientific Research
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2010

A discussion on the representativeness of charcoal from archaeological contexts and their potential for palaeoecological reconstruction is presented. The charcoal deposits studied are the result of human activities and natural processes, difficult to separate on the basis of their effects only. This is why "taphonomy" should not be limited to the study of charcoal, after the extinction of fire. As a result our questioning has been widened to include the entire succession of processes, from past vegetation to the anthracological diagram. We propose a review of the taphonomic processes affecting anthracological assemblages in archaeological contexts, from wood gathering to the analysis of charcoal results. Human practices appear clearly as the first filter determining or conditioning the assemblage. The combustion process can induce a double filter by limiting the taxonomic information and by falsifying the initial quantity of burned wood. Post-depositional agents represent a third level of filters between the vegetation and the anthracological assemblage. Finally, sampling and quantification methods can also induce a distortion of the assemblage. The aim of this paper is to present the state of the discipline today, the problems already solved, and the questions that remain to be studied. © 2009 Elsevier B.V. All rights reserved.

Lorand J.-P.,French Natural History Museum | Alard O.,Montpellier University | Luguet A.,University of Bonn
Earth and Planetary Science Letters | Year: 2010

Highly siderophile elements (Platinum-group elements, Au and Re) are currently assumed to reside inside base metal sulfides (BMS) in the convecting upper mantle. However, fertile lherzolites sampled by Pyrenean orogenic peridotite massifs are unexpectedly rich in 0.5-3 μm large micronuggets of platinum-group minerals (PGM). Among those, sulfides from the laurite-erlichmanite series (Ru, Os(Ir)S(As) 2), Pt-Ir-Os alloys and Pt-Pd-Te-Bi phases (moncheite-merenskyite) are predominant. Not only the BMS phases but also the PGM micronuggets must be taken into account in calculation of the PGE budget of orogenic fertile lherzolites. Laurite is a good candidate for equilibrating the whole-rock budget of Os, Ir and Ru while accounting for supra-chondritic Ru/Ir N. Textural relationships between PGMs and BMS highlight heterogeneous mixing between refractory PGMs (laurite/Pt-Ir-Os alloys) inherited from ancient refractory lithospheric mantle and late-magmatic metasomatic sulfides precipitated from tholeiitic melts. "Low-temperature" PGMs, especially Pt-Pd bismuthotellurides should be added to the list of mineral indicators of lithosphere refertilization process. Now disseminated within fertile lherzolites, "lithospheric" PGMs likely account for local preservation of ancient Os model ages (up to 2 Ga) detected in BMS by in-situ isotopic analyses. These PGMs also question the reliability of orogenic lherzolites for estimating the PGE signature of the Primitive Silicate Earth. © 2009 Elsevier B.V. All rights reserved.

Alabarse F.G.,Charles Gerhardt Institute | Haines J.,Charles Gerhardt Institute | Cambon O.,Charles Gerhardt Institute | Levelut C.,Montpellier University | And 4 more authors.
Physical Review Letters | Year: 2012

Freezing of water in hydrophilic nanopores (D=1.2nm) is probed at the microscopic scale using x-ray diffraction, Raman spectroscopy, and molecular simulation. A freezing scenario, which has not been observed previously, is reported; while the pore surface induces orientational order of water in contact with it, water does not crystallize at temperatures as low as 173K. Crystallization at the surface is suppressed as the number of hydrogen bonds formed is insufficient (even when including hydrogen bonds with the surface), while crystallization in the pore center is hindered as the curvature prevents the formation of a network of tetrahedrally coordinated molecules. This sheds light on the concept of an ubiquitous unfreezable water layer by showing that the latter has a rigid (i.e., glassy) liquidlike structure, but can exhibit orientational order. © 2012 American Physical Society.

Caracas R.,French National Center for Scientific Research | Mainprice D.,Montpellier University | Thomas C.,University of Munster
Geophysical Research Letters | Year: 2010

We determine the elasticity of FeSiO3 perovskite for various spin configurations using density-functional theory calculations. The elastic moduli and the bulk seismic wave velocities are weakly affected by the spin transition. However we show that the intrinsic differences in seismic anisotropy between the high-spin and low-spin phases of Fe-bearing perovskite coupled with lattice preferred orientation that can develop due and during the convection may lead to distinct seismic signatures between the top and the bottom of the lower mantle. These signatures should be detectable in observations and they need to be taken into account in tomographic studies of the Earth's lower mantle. © 2010 by the American Geophysical Union.

Venables J.P.,Montpellier University
Nature communications | Year: 2013

Reprogramming somatic cells into induced pluripotent stem cells (iPSCs) has provided huge insight into the pathways, mechanisms and transcription factors that control differentiation. Here we use high-throughput RT-PCR technology to take a snapshot of splicing changes in the full spectrum of high- and low-expressed genes during induction of fibroblasts, from several donors, into iPSCs and their subsequent redifferentiation. We uncover a programme of concerted alternative splicing changes involved in late mesoderm differentiation and controlled by key splicing regulators MBNL1 and RBFOX2. These critical splicing adjustments arise early in vertebrate evolution and remain fixed in at least 10 genes (including PLOD2, CLSTN1, ATP2A1, PALM, ITGA6, KIF13A, FMNL3, PPIP5K1, MARK2 and FNIP1), implying that vertebrates require alternative splicing to fully implement the instructions of transcriptional control networks.

Bantignies F.,French National Center for Scientific Research | Roure V.,French National Center for Scientific Research | Comet I.,French National Center for Scientific Research | Leblanc B.,French National Center for Scientific Research | And 5 more authors.
Cell | Year: 2011

In Drosophila melanogaster, Hox genes are organized in an anterior and a posterior cluster, called Antennapedia complex and bithorax complex, located on the same chromosome arm and separated by 10 Mb of DNA. Both clusters are repressed by Polycomb group (PcG) proteins. Here, we show that genes of the two Hox complexes can interact within nuclear PcG bodies in tissues where they are corepressed. This colocalization increases during development and depends on PcG proteins. Hox gene contacts are conserved in the distantly related Drosophila virilis species and they are part of a large gene interaction network that includes other PcG target genes. Importantly, mutations on one of the loci weaken silencing of genes in the other locus, resulting in the exacerbation of homeotic phenotypes in sensitized genetic backgrounds. Thus, the three-dimensional organization of Polycomb target genes in the cell nucleus stabilizes the maintenance of epigenetic gene silencing. © 2011 Elsevier Inc.

Xu W.,French National Institute for Agricultural Research | Xu W.,French National Center for Scientific Research | Dubos C.,Montpellier University | Lepiniec L.,French National Institute for Agricultural Research | Lepiniec L.,French National Center for Scientific Research
Trends in Plant Science | Year: 2015

Flavonoids are widely known for the colors they confer to plant tissues, their contribution to plant fitness and health benefits, and impact on food quality. As convenient biological markers, flavonoids have been instrumental in major genetic and epigenetic discoveries. We review recent advances in the characterization of the underlying regulatory mechanisms of flavonoid biosynthesis, with a special focus on the MBW (MYB-bHLH-WDR) protein complexes. These proteins are well conserved in higher plants. They participate in different types of controls ranging from fine-tuned transcriptional regulation by environmental factors to the initiation of the flavonoid biosynthesis pathway by positive regulatory feedback. The MBW protein complexes provide interesting models for investigating developmentally or environmentally controlled transcriptional regulatory networks. © 2014 Elsevier Ltd.

Lagabrielle Y.,CNRS Geosciences Laboratory of Rennes | Vitale Brovarone A.,CNRS Institute of Mineralogy, Materials Physics and Cosmochemistry | Ildefonse B.,Montpellier University
Earth-Science Reviews | Year: 2015

Tethyan ophiolites show an apparent poorly organized association of ultramafic and mafic rocks. By contrast to the complete mantle-crustal sections of Semail-type ophiolite sheets, Tethyan ophiolites are characterized by a smaller amount of mafic rocks (gabbros and basalts), by the absence of any sheeted dyke complex and by the frequent occurrence of oceanic sediments stratigraphically overlying mantle-derived peridotites and associated gabbroic intrusions. Therefore, they are considered as typical remnants of oceanic lithosphere formed in slow-spreading environment or in ocean-continent transition at distal passive margins. In the very first models of formation of the Tethyan ophiolites, in the years 1980, the geodynamical processes leading to mantle unroofing were poorly understood due to the paucity of data and concepts available at that time from the present-day oceans. In particular, at that time, little work had focused on the distribution, origin and significance of mafic rocks with respect to the dominant surrounding ultramafics. Here, we reconsider the geology of some typical metaophiolites from the Western Alps and Corsica, and we show how results from the past decade obtained in the current oceans ask for reassessing the significance of the Tethyan ophiolites in general. Revisited examples include a set of representative metaophiolites from the blueschists units of the Western Alps (Queyras region) and from Alpine Corsica (Golo Valley). Field relationships between the ophiolitic basement and the metasedimentary/metavolcanic oceanic cover are described, outlining a typical character of the Tethyan ophiolite lithological associations. Jurassic marbles and polymictic ophiolite metabreccias are unconformably overlying the mantle-gabbo basement, in a way strictly similar to what is observed in the non-metamorphic Appennine ophiolites or Chenaillet massif. This confirms that very early tectonic juxtaposition of ultramafic and mafic rocks occurred in the oceanic domain before subduction. This juxtaposition resulted from tectonic activity that is now assigned to the development of detachment faults and to the formation of Oceanic Core Complexes (OCCs) at the axis of slow spreading ridges. This fundamental Plate Tectonics process is responsible for the exhumation and for the axial denudation of mantle rocks and gabbros at diverging plate boundaries. In addition, field relationships between the discontinuous basaltic formations and the ultramafic-mafic basement indicate that this tectonic stage is followed or not by a volcanic stage. We discuss this issue in the light of available field constraints. © 2014 Elsevier B.V.

Bakalowicz M.,Montpellier University
Environmental Earth Sciences | Year: 2015

Karst landforms were first described and studied in Mediterranean regions, where these common landforms display their main hydrological characteristics. For this reason, Mediterranean karst is often considered to be the common reference. However, when we examine the general settings of Mediterranean karst and their groundwater resources more carefully, it becomes obvious that carbonate formations around the Mediterranean have been subject to various and complex conditions of development and functioning. This paper is an attempt to characterize the various types of carbonate karst aquifers present in the Mediterranean region according to the geological events that led to the development of different karst conditions. In terms of geological conditions, three major events caused the development of specific karst drainage structures that produced the various characteristics of Mediterranean carbonate aquifers: the Messinian Salinity Crisis (MSC) at the end of the Miocene, which caused rivers to incise deep valleys to reach the remaining sea, 1500–2500 m below the present sea level;cold periods during the Quaternary that caused weathering of the epikarst, even its destruction, which led to the development of a thick scree cover above an elevation of 1200–1500 m; andpost-Miocene tectonics that generated extensional horst and graben structures, favored hydrothermalism and deep CO2 flux, and caused continental sediments to fill in large basins in compressional environments.The main consequence of these complex geological conditions is the existence of large aquifers with successive karst structures developed at different depths and large storage capacities. When karstification occurred along the coasts, it may have caused carbonate aquifers to become connected to the sea, sometimes at great depths. Although it may be possible to provide an overall estimate of resources relatively easily from climatic and geological data, a groundwater storage assessment requires detailed knowledge of aquifer functioning and local geological evolution. Because of the complexity of karst development in Mediterranean regions, it is unrealistic to expect to manage them in a sustainable way without a thorough assessment of these karst aquifers. © 2015, Springer-Verlag Berlin Heidelberg.

Sadhukhan S.,Jogesh Chandra Choudhury College | Gouze P.,Montpellier University | Dutta T.,St Xaviers College
Journal of Hydrology | Year: 2012

Numerical programs for simulating flow and reactive transport in porous media is essential for predicting reservoir properties related to CO 2 sequestration performance, subsurface storage and risk assessment. In this paper we solve the Navier Stokes' equation using finite difference method, on a simulated porous rock structure, to study the velocity distribution of fluid flowing through it under a constant pressure gradient. A reactive solute carried through the fluid is allowed to interact with the minerals in the rock. This chemical reaction dissolves the mineral which changes the rock structure thus affecting its flow properties. These changes of flow properties are studied with variation in reactive solute concentration and pressure field. The different mechanisms of dissolution responsible for the variation of flow properties for the different parameters is predicted. Before the onset of homogeneous dissolution, variation in porosity follows a power-law behaviour with change in permeability when the latter is scaled by the concentration of the reactive species. The simulation results are compared with available experimental data and found to give a reasonable match. © 2012 Elsevier B.V.

Rousset F.,Montpellier University | Rousset F.,Institute Of Biologie Computationnelle | Ferdy J.-B.,CNRS Biological Evolution and Diversity Laboratory
Ecography | Year: 2014

Spatial autocorrelation is a well-recognized concern for observational data in general, and more specifically for spatial data in ecology. Generalized linear mixed models (GLMMs) with spatially autocorrelated random effects are a potential general framework for handling these spatial correlations. However, as the result of statistical and practical issues, such GLMMs have been fitted through the undocumented use of procedures based on penalized quasi-likelihood approximations (PQL), and under restrictive models of spatial correlation. Alternatively, they are often neglected in favor of simpler but more questionable approaches. In this work we aim to provide practical and validated means of inference under spatial GLMMs, that overcome these limitations. For this purpose, a new software is developed to fit spatial GLMMs. We use it to assess the performance of likelihood ratio tests for fixed effects under spatial autocorrelation, based on Laplace or PQL approximations of the likelihood. Expectedly, the Laplace approximation performs generally slightly better, although a variant of PQL was better in the binary case. We show that a previous implementation of PQL methods in the R language, glmmPQL, is not appropriate for such applications. Finally, we illustrate the efficiency of a bootstrap procedure for correcting the small sample bias of the tests, which applies also to non-spatial models. © 2014 The Authors.

De Laverny P.,University of Nice Sophia Antipolis | Recio-Blanco A.,University of Nice Sophia Antipolis | Worley C.C.,University of Nice Sophia Antipolis | Plez B.,Montpellier University
Astronomy and Astrophysics | Year: 2012

Context.Large grids of synthetic spectra covering a wide range of stellar parameters are essential tools for different stellar and (extra-) Galactic physical applications. They can be used for the automatic parametrisation of stellar spectra such as that performed by the AMBRE project whose main goal is to determine the stellar atmospheric parameters of a few hundred thousands of archived spectra of four ESO spectrographs. Aims. To fulfil the needs of AMBRE and similar future projects, we computed a grid of synthetic spectra over the whole optical domain for cool to very cool stars of any luminosity (from dwarfs to supergiants) with metallicities varying from 10-5 to 10 times the solar metallicity, and considering large variations in the chemical composition of the a-elements. Methods. In these spectrum computations, we used new generation MARCS model atmospheres and the Turbospectrum code for radiative transfer. We also took into account atomic and molecular linelists that were as complete as possible and adopted, in the spectral synthesis, the same physical assumptions and input data as in the MARCS models. This allowed us to present a grid in which there is a high consistency between the atmosphere models and the synthetic spectra. Results.We present a new grid of 16 783 high resolution spectra over the wavelength range 3000 Å to 12 000 Å computed at a spectral resolution higher than 150 000. Normalised and absolute flux versions are available over a wide range of stellar atmospheric parameters for stars of FGKM spectral types. The parameters covered are 2500 K ≤ T eff = 8000 K,-0.5 ≤ log(g) ≤ 5.5 dex, and-5.0 ≤ [M/H] ≤ +1.0 dex. Moreover, for each combination of these stellar parameters, five different values of the enrichment in a-elements were considered (0.0, ± 0.2 dex and ± 0.4 dex around the standard values). This library is thus relevant to any stellar type and luminosity class, present in old and intermediate-age stellar populations with chemical composition varying from extremely metal-poor to metal-rich. This grid is made publicly available through the POLLUX database (about 50% of the spectra have been included in this database) and in FITS format upon request to the authors. © 2012 ESO.

Van Marle A.J.,Catholic University of Leuven | Meliani Z.,University of Paris Descartes | Marcowith A.,Montpellier University
Astronomy and Astrophysics | Year: 2012

Context. Numerical models of the wind-blown bubble of massive stars usually only account for the wind of a single star. However, since massive stars are usually formed in clusters, it would be more realistic to follow the evolution of a bubble created by several stars. Aims. We develop a two-dimensional (2D) model of the circumstellar bubble created by two massive stars, a 40 M star and a 25 M star, and follow its evolution. The stars are separated by approximately 16 pc and surrounded by a cold medium with a density of 20 particles per cm 3. Methods. We use the MPI-AMRVAC hydrodynamics code to solve the conservation equations of hydrodynamics on a 2D cylindrical grid using time-dependent models for the wind parameters of the two stars. At the end of the stellar evolution (4.5 and 7.0 million years for the 40 and 25 M stars, respectively), we simulate the supernova explosion of each star. Results. Each star initially creates its own bubble. However, as the bubbles expand they merge, creating a combined, aspherical bubble. The combined bubble evolves over time, influenced by the stellar winds and supernova explosions. Conclusions. The evolution of a wind-blown bubble created by two stars deviates from that of the bubbles around single stars. In particular, once one of the stars has exploded, the bubble is too large for the wind of the remaining star to maintain and the outer shell starts to disintegrate. The lack of thermal pressure inside the bubble also changes the behavior of circumstellar features close to the remaining star. The supernovae are contained inside the bubble, which reflects part of the energy back into the circumstellar medium. © ESO, 2012.

Bremaud I.,Montpellier University
Journal of the Acoustical Society of America | Year: 2012

The acoustical properties of wood for instruments have mostly been studied on a few archetypal woods in Western musical instruments. The objective of this paper is to extend knowledge on the diversity in wood properties and uses in instruments from different geo-cultural areas. A wide set of data has been collected on vibrational properties of 452 species, through experiments and literature survey. Property distributions within broad categories confirm the known characteristics of softwoods, but also evidence specificities of tropical hardwoods compared to temperate-zone species. A relational database has been created to link wood properties and uses in musical instruments of the world. Two case studies on acoustically important functions in different geo-cultural areas show contrasted trends: (i) species used for xylophone bars and slit-drums in different continents all share a very low internal friction, (ii) on the contrary, the only characteristic common to soundboards' woods is a lower than average density, whereas their acoustical properties differ widely between them and with the Western standard in wood choice. All these materials being nevertheless adapted to their context, cultural specificities in the structure, playing mode and sonority preferences should also be taken into account. © 2012 Acoustical Society of America.

Coey C.A.,University of Cincinnati | Varlet M.,University of Cincinnati | Varlet M.,Montpellier University | Richardson M.J.,University of Cincinnati
Frontiers in Human Neuroscience | Year: 2012

Traditional theories of cognitive science have typically accounted for the organization of human behavior by detailing requisite computational/representational functions and identifying neurological mechanisms that might perform these functions. Put simply, such approaches hold that neural activity causes behavior. This same general framework has been extended to accounts of human social behavior via concepts such as "common-coding" and "co-representation" and much recent neurological research has been devoted to brain structures that might execute these social-cognitive functions. Although these neural processes are unquestionably involved in the organization and control of human social interactions, there is good reason to question whether they should be accorded explanatory primacy. Alternatively, we propose that a full appreciation of the role of neural processes in social interactions requires appropriately situating them in their context of embodied-embedded constraints. To this end, we introduce concepts from dynamical systems theory and review research demonstrating that the organization of human behavior, including social behavior, can be accounted for in terms of self-organizing processes and lawful dynamics of animal-environment systems. Ultimately, we hope that these alternative concepts can complement the recent advances in cognitive neuroscience and thereby provide opportunities to develop a complete and coherent account of human social interaction. © 2012 Coey, Varlet and Richardson.

Zhilina E.,Russian Academy of Sciences | Esyunina D.,Russian Academy of Sciences | Brodolin K.,Montpellier University | Kulbachinskiy A.,Russian Academy of Sciences
Nucleic Acids Research | Year: 2012

A transcription initiation factor, the σ 70 subunit of Escherichia coli RNA polymerase (RNAP) induces transcription pausing through the binding to a promoter-like pause-inducing sequence in the DNA template during transcription elongation. Here, we investigated the mechanism of σ-dependent pausing using reconstituted transcription elongation complexes which allowed highly efficient and precisely controlled pause formation. We demonstrated that, following engagement of the σ subunit to the pause site, RNAP continues RNA synthesis leading to formation of stressed elongation complexes, in which the nascent RNA remains resistant to Gre-induced cleavage while the transcription bubble and RNAP footprint on the DNA template extend in downstream direction, likely accompanied by DNA scrunching. The stressed complexes can then either break σ-mediated contacts and continue elongation or isomerize to a backtracked conformation. Suppressing of the RNAP backtracking decreases pausing and increases productive elongation. On the contrary, core RNAP mutations that impair RNAP interactions with the downstream part of the DNA template stimulate pausing, presumably by destabilizing the stressed complexes. We propose that interplay between DNA scrunching and RNAP backtracking may have an essential role in transcription pausing and its regulation in various systems. © 2011 The Author(s).

Briant L.,Montpellier University | Despres P.,Institute Pasteur Paris | Choumet V.,Institute Pasteur Paris | Misse D.,IRD Montpellier
Virology | Year: 2014

Due to climate change and the propagation of competent arthropods worldwide, arboviruses have become pathogens of major medical importance. Early transmission to vertebrates is initiated by skin puncture and deposition of virus together with arthropod saliva in the epidermis and dermis. Saliva components have the capacity to modulate skin cell responses by enhancing and/or counteracting initial replication and establishment of systemic viral infection. Here, we review the nature of the cells targeted by arboviruses at the skin level and discuss the type of cellular responses elicited by these pathogens in light of the immunomodulatory properties of arthropod vector-derived salivary factors injected at the inoculation site. Understanding cutaneous arbovirus-host interactions may provide new clues for the design of future therapeutics. © 2014 .

Misra S.,ETH Zurich | Burg J.-P.,ETH Zurich | Mainprice D.,Montpellier University
Journal of Geophysical Research: Solid Earth | Year: 2011

Strain and strain rate partitioning in partially molten rocks are two of the important mechanisms that govern the process of coupling and/or decoupling of the partially molten lithosphere. Consequently, the proportion of partial melt and crystals and their network in partially molten rocks influence the degree of the partitioning along with the bulk rheology of the system. This study explores the possible role of finite strain and strain rate on the rate and volume of partial melting and crystallization in a metapelitic system undergoing deformation. Cylinders of synthetic quartz-muscovite aggregate (7:3 volume ratio) were deformed in torsion at 750C, 300 MPa and constant shear strain rate (γ = 3 × 10-4 s-1) for finite shear strains (γ) 1-15. The deformed samples were studied along the longitudinal tangential (LT) and axial (LA) sections to obtain the data along a range of strain rates for a given finite strain and vice versa. The results showed that deformation plays an important role on the kinetics of partial melting and crystallization. With increasing strain rate, amount and rate of crystallization comprise the volumetrically dominant process compared to partial melting at a given finite strain. In contrast, when the strain rate is constant, partial melting is the dominant process over crystallization up to moderate strain (γ < 5). The dominant process reverses at higher strain, and the system shows more crystallization than partial melting. Application of the experimental data to geological systems implies that for metapelites a significant amount (∼20%) of partial melt can generate at high strain rate and moderate strain (γ ∼ 7), but at high strain (γ = 15) the system is melt depleted. Under such conditions, decoupling should take place in brittle-ductile mode. On the other hand, rocks undergoing deformation with low strain rates and strain (γ < 3) contain more than 25% partial melt, which can act as a major decoupling agent by localizing ductile shear zones. Copyright © 2011 by the American Geophysical Union.

Meynard C.N.,Montpellier SupAgro | Kaplan D.M.,Montpellier University
Ecography | Year: 2012

Species distribution models (SDMs) have been widely used in ecology, biogeography, and conservation. Although ecological theory predicts that species occupancy is dynamic, the outputs of SDMs are generally converted into a single occurrence map, and model performance is evaluated in terms of success to predict presences and absences. The aim of this study was to characterize the effects of a gradual response in species occupancy to environmental gradients into the performance of SDMs. First we outline guidelines for the appropriate simulation of artificial species that allows controlling for gradualism and prevalence in the occupancy patterns over an environmental gradient. Second, we derive theoretical expected values for success measures based on presence-absence predictions (AUC, Kappa, sensitivity and specificity). And finally we used artificial species to exemplify and test the effect of a gradual probabilistic occupancy response to environmental gradients on SDM performance. Our results show that when a species responds gradually to an environmental gradient, conventional measures of SDM predictive success based on presence-absence cannot be expected to attain currently accepted performance values considered as good, even for a model that recovers perfectly well the true probability of occurrence. A gradual response imposes a theoretical expected value for these measures of performance that can be calculated from the species properties. However, irrespective of the statistical modeling strategy used and of how gradual the species response is, one can recover the true probability of occurrence as a function of environmental variables provided that species and sample prevalence are similar. Therefore, model performance based on presence-absence should be judged against the theoretical expected value rather than to absolute values currently in use such as AUC > 0.8. Overall, we advocate for a wider use of the probability of occurrence and emphasize the need for further technical developments in this sense. © 2011 The Authors. Ecography © 2011 Nordic Society Oikos.

Kaniewski D.,Toulouse 1 University Capitole | Van Campo E.,Toulouse 1 University Capitole | Boiy T.,Catholic University of Leuven | Terral J.-F.,Montpellier University | And 2 more authors.
Biological Reviews | Year: 2012

Our knowledge of the origins of olive tree domestication in the Middle East and on the processes governing its extension and persistence in different vegetation types from prehistory through antiquity to modern times derives from diverse sources, spanning the biological sciences to the humanities. Nonetheless, it lacks a robust overview that may lead to floating interpretations. This is especially true in the Middle East, considered as the cradle of agriculture, and where the evolutionary history of this emblematic tree is intertwined with that of civilizations. Olive fruit, oil and wood have been, since Prehistoric times, characteristic products of the lands bordering the Mediterranean Sea. In the domestic economy of these countries, the olive tree gradually became a traditional tree crop since the first oil extraction, through the emergence of regional commerce that accompanied the rise and fall of early Near-Middle Eastern urbanism, until the development of modern trade, with an oil production estimated at circa 3000000 tons per year. The rising importance of the olive tree in human life has turned the tree into an endless source of fascination in the Aegean and Eastern Mediterranean, a symbol and a sacred tree, widely cited in the Bibles, the Koran, and in ancient literature. Here we argue that advances in radiocarbon chronology, palaeobotany, genetics, and archaeology-history have profoundly refined the history of olive trees in the Middle East. This review shows that the heartland of primary olive domestication must be enlarged to the Levant and not only focus on the Jordan Valley. The domestication of the olive tree is a long and ongoing process, linked to the early production of oil and the development of the olive trade. We also suggest that the olive tree became a particular icon, a sacred tree, during the Biblical period in the Levant. © 2012 The Author. Biological Reviews © 2012 Cambridge Philosophical Society.

Raevel V.,CNRS Center of Evolutionary and Functional Ecology | Violle C.,CNRS Center of Evolutionary and Functional Ecology | Munoz F.,Montpellier University
Oikos | Year: 2012

Successions are a central issue of ecological theory. They are governed by changes in community assembly processes that can be tracked by species' traits. While single-trait-based approaches have been mostly promoted to address community assembly, ecological strategies actually encompass tradeoffs between multiple traits that are relevant to succession theory. We analyzed plant ecological strategies along a 140-year-long succession primary succession of 52 vertical outcrop communities after roadwork. We performed a RLQ analysis to relate six functional traits, associated with resource acquisition, competition, colonization ability and phenology, to the age of the outcrops. We found the prominence of two main axes of specialization, one related to resource acquisition and the other to reproduction and regeneration. We further examined the community-level variation in ecological strategies to assess the abiotic and biotic drivers of community assembly. Using trait-based statistics of functional richness, regularity and divergence, we found that different processes drove the variation in ecological strategies along the axes of specialization. In late succession, functional convergence was detected for the traits related to resource acquisition as a signature of habitat filtering, while the coexistence of contrasted strategies was found for the traits related to reproduction and regeneration as a result of spatial micro-heterogeneity. We observed a lack of niche differentiation along the succession, revealing a weak importance of biotic interactions for the regulation of community assembly in the outcrops. Overall, we highlight a prominent role of habitat filtering and spatial micro-heterogeneity in driving the primary succession governed by water and nutrient limitation. © 2012 The Authors. Oikos © 2012 Nordic Society Oikos.

Carles R.,Montpellier University
Zeitschrift fur Angewandte Mathematik und Physik | Year: 2015

We review different properties related to the Cauchy problem for the (nonlinear) Schrödinger equation with a smooth potential. For energy-subcritical nonlinearities and at most quadratic potentials, we investigate the necessary decay in space in order for the Cauchy problem to be locally (and globally) well posed. The characterization of the minimal decay is different in the case of super-quadratic potentials. © 2015, Springer Basel.

Jaber S.,Montpellier University
Current Opinion in Anaesthesiology | Year: 2010

Purpose of review: The aims of this review are: to discuss the physiological rationale for noninvasive respiratory support (NRS) in the perioperative period; to give some practical recommendations to safely apply NRS; and to review available clinical data on preventive and curative NRS after cardiac, thoracic and abdominal surgery. Recent findings: The most important morbid postoperative pulmonary complication is atelectasis formation, which increases significantly the risk for pneumonia and hypoxic acute respiratory failure. NRS refers to techniques allowing respiratory support without the need for an invasive airway. Two types of NRS are commonly used: noninvasive continuous positive airway pressure (nCPAP) and noninvasive positive pressure ventilation (nPPV). NRS may be an important tool to prevent (prophylactic treatment) or to treat acute respiratory failure avoiding intubation (curative treatment). The aims of NRS are: to partially compensate for the affected respiratory function by reducing the work of breathing; to improve alveolar recruitment with better gas exchange (oxygenation and ventilation); to reduce left ventricular afterload, increasing cardiac output and improving hemodynamics. Evidence suggests that NRS has been proven to be an effective strategy to reduce intubation rates, nosocomial infections, ICU and hospital lengths of stay, morbidity and mortality in postoperative patients. However, before initiating NRS any surgical complications must be treated. Summary: The application of postoperative NRS by a trained and experienced ICU team, with careful patient selection, should optimize patient outcome. © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins.

D'Errico M.E.,Stanford University | Warren J.M.,Stanford University | Godard M.,Montpellier University
Geochimica et Cosmochimica Acta | Year: 2016

Ultraslow spreading at mid-ocean ridges limits melting due to on-axis conductive cooling, leading to the prediction that peridotites from these ridges are relatively fertile. To test this, we examined abyssal peridotites from the Gakkel Ridge, the slowest spreading ridge in the global ocean ridge system. Major and trace element concentrations in pyroxene and olivine minerals are reported for 14 dredged abyssal peridotite samples from the Sparsely Magmatic (SMZ) and Eastern Volcanic (EVZ) Zones. We observe large compositional variations among peridotites from the same dredge and among dredges in close proximity to each other. Modeling of lherzolite trace element compositions indicates varying degrees of non-modal fractional mantle melting, whereas most harzburgite samples require open-system melting involving interaction with a percolating melt. All peridotite chemistry suggests significant melting that would generate a thick crust, which is inconsistent with geophysical observations at Gakkel Ridge. The refractory harzburgites and thin overlying oceanic crust are best explained by low present-day melting of a previously melted heterogeneous mantle. Observed peridotite compositional variations and evidence for melt infiltration demonstrates that fertile mantle components are present and co-existing with infertile mantle components. Melt generated in the Gakkel mantle becomes trapped on short length-scales, which produces selective enrichments in very incompatible rare earth elements. Melt migration and extraction may be significantly controlled by the thick lithosphere induced by cooling at such slow spreading rates. We propose the heterogeneous mantle that exists beneath Gakkel Ridge is the consequence of ancient melting, combined with subsequent melt percolation and entrapment. © 2015 The Authors.

Sauliere-Nzeh A.N.,French Institute of Health and Medical Research | Sauliere-Nzeh A.N.,Institut Universitaire de France | Corbani M.,Montpellier University
Journal of Biological Chemistry | Year: 2010

Techniques for analyzing the membrane diffusion of molecules are the most promising methods for investigating the compartmentalization of G-protein-coupled receptors, particularly as relevant to receptor signaling processes. Here, we report fluorescence recovery after photobleaching (FRAP) measurements performed at variable spot radius for human mu opioid (hMOP) receptors on SH-SY5Y neuroblastoma cells in the presence of ligands. Although an antagonist did not affect the behavior of the receptors compared with the basal state, two different agonists, DAMGO and morphine, caused markedly different changes to receptor diffusion. Like receptors in the absence of ligand, receptors bound to morphine exhibited diffusion confined to joined semipermeable domains, but with smaller domain size and diffusion coefficient. This effect was inhibited by pertussis toxin, strongly suggesting that this dynamic behavior is associated with early steps of signaling. In the presence of DAMGO, half of the receptors displayed free long-range diffusion and the other half were confined to smaller isolated domains. Hypertonic sucrose buffer suppressed this effect, which we attribute to receptor entry into clathrin-coated pits. It is likely that the observation of distinct receptor dynamics in the presence of DAMGO and morphine involves the agonist-selective phosphorylation of the receptor. © 2010 by The American Society for Biochemistry and Molecular Biology, Inc.

Duputie A.,CNRS Center of Evolutionary and Functional Ecology | Duputie A.,University of Texas at Austin | Massol F.,University of Texas at Austin | Massol F.,IRSTEA | And 3 more authors.
Ecology Letters | Year: 2012

Species may be able to respond to changing environments by a combination of adaptation and migration. We study how adaptation affects range shifts when it involves multiple quantitative traits evolving in response to local selection pressures and gene flow. All traits develop clines shifting in space, some of which may be in a direction opposite to univariate predictions, and the species tracks its environmental optimum with a constant lag. We provide analytical expressions for the local density and average trait values. A species can sustain faster environmental shifts, develop a wider range and greater local adaptation when spatial environmental variation is low (generating low migration load) and multitrait adaptive potential is high. These conditions are favoured when nonlinear (stabilising) selection is weak in the phenotypic direction of the change in optimum, and genetic variation is high in the phenotypic direction of the selection gradient. © 2012 Blackwell Publishing Ltd/CNRS.

Helmlinger D.,Montpellier University
Transcription | Year: 2012

The SAGA complex is a conserved, multifunctional co-activator that controls the transcription of many inducible genes in response to environmental changes. Recent studies have provided new insights into the functions of one of its subunits, Tra1/TRRAP, and suggest that it controls SAGA activity in response to external stimuli. © 2012 Landes Bioscience.

Manel N.,New York University | Manel N.,Montpellier University | Hogstad B.,New York University | Hogstad B.,Howard Hughes Medical Institute | And 5 more authors.
Nature | Year: 2010

Dendritic cells serve a key function in host defence, linking innate detection of microbes to activation of pathogen-specific adaptive immune responses1,2. Whether there is cell-intrinsic recognition of human immunodeficiency virus (HIV) by host innate patternrecognition receptors and subsequent coupling to antiviral T-cell responses is not yet known3. Dendritic cells are largely resistant to infection with HIV-14, but facilitate infection of cocultured T-helper cells through a process of trans-enhancement5,6. Here we show that, when dendritic cell resistance to infection is circumvented7,8, HIV-1 induces dendritic cell maturation, an antiviral type I interferon response and activation of T cells. This innate response is dependent on the interaction of newly synthesized HIV-1 capsid with cellular cyclophilin A (CYPA) and the subsequent activation of the transcription factor IRF3. Because the peptidylprolyl isomerase CYPA also interacts with HIV-1 capsid to promote infectivity, our results indicate that capsid conformation has evolved under opposing selective pressures for infectivity versus furtiveness. Thus, a cell-intrinsic sensor for HIV-1 exists in dendritic cells and mediates an antiviral immune response, but it is not typically engaged owing to the absence of dendritic cell infection. The virulence of HIV-1 may be related to evasion of this response, the manipulation of which may be necessary to generate an effective HIV-1 vaccine. © 2010 Macmillan Publishers Limited. All rights reserved.

Nitze F.,Umea University | Abou-Hamad E.,Umea University | Abou-Hamad E.,Montpellier University | Wgberg T.,Umea University
Carbon | Year: 2011

Chemical vapour deposition (CVD) represents a cheap and versatile method to produce carbon nanostructures. Here we present how we by using a standard CVD setup together with Pd nano particles as a catalyst can produce helical fibers with very periodic pitch, helicity, and narrow diameter distribution. The C 60 supported Pd catalyst particles are produced by a wet chemistry process and applied to silicon substrates. By raising the growth temperature from 550 °C to 800 °C we can tune the growth products from helical carbon fibers to straight hollow carbon fibers and finally to carbon nanotubes at the highest temperatures. In the intermediate temperature region of 650 °C a mixture of all three components appears. At 550 °C the efficiency of the process is optimized by the amount of water during the growth. Different from most previous studies we can detect most of the catalyst particles embedded in the grown structures. In all fibers the catalyst particles are situated exactly in the middle of the fibers suggesting a two-directional growth. From the shape of the catalyst particles and by adopting a simple model we conclude that the fibers coil due to blocked carbon diffusion pathways on or through the catalyst particles. © 2010 Elsevier Ltd. All rights reserved.

Supuran C.T.,Universitadeglistudi Of Firenze | Winum J.-Y.,Montpellier University
Expert Opinion on Drug Discovery | Year: 2015

Introduction: Carbonic anhydrase (CA) IX is one of the proteins that are involved in cancerogenesis in hypoxic breast tumors. Indeed, it is present in high amounts in hypoxic tumor cells, where it plays a crucial role in metabolic reprogramming due to the scarcity of oxygen, triggered by the hypoxia inducible factor 1 transcription factor. In such tumors, CA IX is involved, along with other proteins, in tumor pH regulation and its survival in a harsh environment (including hypoxia and acidity). CA IX is also validated as an imaging and treatment target for hypoxic tumors and metastasis.Areas covered: In this review, the authors highlight the wealth of CA IX inhibitors currently in the literature. This includes the two most investigated classes of compounds being the sulfonamides and the coumarins, including their isosteres.Expert opinion: The most advanced CA IX inhibitors candidates, which demonstrate antimetastatic activity in breast cancer, are the sulfonamides, with one compound (SLC-0111) currently in Phase I clinical development. The fact that this first inhibitor has progressed could increase interest in the development of conceptually novel antitumor/antimetastic drugs belonging to the CA inhibitors class. © 2015 Informa UK, Ltd.

Lorand J.-P.,French Natural History Museum | Alard O.,Montpellier University
Mineralogy and Petrology | Year: 2011

Cobalt-bearing pyrite (0.5-2.0 wt.% Co) is abnormally abundant (up to 35 vol.% of the total volume of the sulfide phase) in some eastern Pyrenean peridotite massifs, compared to pieces of subcontinental mantle studied so far for sulfides. Pyrite occurs as vermicular intergrowths inside pentlandite and/or chalcopyrite or as coarser, blocky grains in the intergranular pores of host peridotites. Those different pyrites are characterized by different platinum-group element systematics (measured by laser ablation microprobe and ICP-MS). Vermicular pyrite intergrown with pentlandite displays Os-, Ir-, Ru- and Rh-enriched chondrite normalized PGE patterns of Monosulfide solid solution (Mss). In contrast, coarse-grained intergranular ("blocky") pyrites, are PGE-poor. Chalcophile trace elements (i. e. Zn, Pb, Ag, Au) that are not usually concentrated in mantle-derived sulfides were commonly detected. By contrast, selenium contents are generally low, yielding thus pyrite with high S/Se ratio (>10 5), consistent with a sedimentary sulfur source. Pyrite microtextures and chalcophile trace element contents support a process of assimilation of crustal sulfur from the metamorphosed sedimentary country rocks. These latter generated highly reactive CO 2-S fluids, which were injected into structural discontinuities of the lherzolitic bodies. Sulfur has reacted at T = 300-550°C with pre-existing, mantle-derived, metal-rich sulfide assemblages (pentlandite-chalcopyrite). Addition of crustal sulfur did produce Mss which, on cooling, exsolved the Os-rich pyrite in addition to pentlandite. The coarse-grained pyrite types have crystallized directly from S-rich fluids. © 2010 Springer-Verlag.

Djamour Y.,P.A. College | Vernant P.,Montpellier University | Nankali H.R.,National Cartographic Center | Tavakoli F.,National Cartographic Center
Earth and Planetary Science Letters | Year: 2011

A network of continuous GPS stations has been installed in NW Iran since 2005 to complement the survey GPS network already existing in the region. We present the 1999-2009 GPS-derived velocity field for this region based on the continuous and survey-mode observations. The results confirm a right lateral slip of 7 ± 1. mm/yr for the North Tabriz fault, in agreement with previous studies. This rate is consistent with earthquakes of magnitude 7-7.3 and recurrence times of 250-300. yr. The higher spatial coverage of the new network shows that deformation is localized in the vicinity of the Chalderan, south Gailatu-Siah Cheshmeh-Khoy fault and the North Tabriz fault. However the eastern end of the North Tabriz fault appears to cross Mount Bozgush rather than following its southern foothills. This new velocity field does not indicate the 8. mm/yr of NNE-SSW extension suggested earlier for the region, but rather shows lower extension of 1-2 ± 1. mm/yr across the eastern segment of the North Tabriz fault and the Talesh. To the west, the Chalderan and the western North Tabriz fault segment act like pure strike slip faults without significant extension or compression. The denser network in the Rudbar earthquake region (Ms 7.3, 1992) shows no significant motion across the fault, suggesting that the recurrence time of earthquakes like the Rudbar event must be very long. The lack of substantial compressive strain and the sharp azimuth change of the velocity vectors in the transition zone from Arabia to Lesser Caucasus motion imply that processes other than "extrusion", possibly related to old subduction or delamination, contribute to active deformation. © 2011 Elsevier B.V.

Kurtyka O.,Lancaster University | Mahenc P.,Montpellier University
Journal of Environmental Economics and Management | Year: 2011

We investigate second-best optimal taxation of the polluting variety of a product in a Bertrand duopoly with differentiated varieties. The analysis provides novel insight on a useful social function of environmental regulation. Besides internalizing the environmental externality, the taxation of the polluting variety improves the matching of consumers and product varieties, and so creates a socially desirable business switching between the differentiated varieties. © 2011 Elsevier Inc.

Huson D.H.,University of Tubingen | Scornavacca C.,University of Tubingen | Scornavacca C.,Montpellier University
Systematic Biology | Year: 2012

Dendroscope 3 is a new program for working with rooted phylogenetic trees and networks. It provides a number of methods for drawing and comparing rooted phylogenetic networks, and for computing them from rooted trees. The program can be used interactively or in command-line mode. The program is written in Java, use of the software is free, and installers for all 3 major operating systems can be downloaded from www.dendroscope.org. [Phylogenetic trees; phylogenetic networks; software.] © 2012 The Author(s).

Suc J.-P.,University Pierre and Marie Curie | Fauquette S.,Montpellier University
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2012

Northern Hemisphere vegetation is generally zoned as a consequence of latitudinal and altitudinal gradients. Temperature reconstruction from three successive pollen floral assemblages (of Tortonian, Messinian and Zanclean age) from the eastern Pyrenees has been used to estimate the altitudinal evolution of the uplifted Cerdanya Basin and its surrounding massifs. A new method has been developed for the uplifted basins, which completes that already applied to pollen floras from coastal marine deposits close to mountains. In contrast to previous hypotheses, it seems that the eastern Pyrenees occurred at a lower altitude in the Late Miocene before continuous uplift began 10. Ma ago. The rate of this uplift ranged between 0.06 and 0.12. mm/yr. © 2012 Elsevier B.V.

Habib M.,University Paris Diderot | Paul C.,Montpellier University
Computer Science Review | Year: 2010

Modular decomposition is a technique that applies to (but is not restricted to) graphs. The notion of a module naturally appears in the proofs of many graph theoretical theorems. Computing the modular decomposition tree is an important preprocessing step to solve a large number of combinatorial optimization problems. Since the first polynomial time algorithm in the early 1970's, the algorithmic of the modular decomposition has known an important development. This paper survey the ideas and techniques that arose from this line of research. © 2010.

Morin-Brureau M.,Montpellier University
Epilepsia | Year: 2012

We previously reported that blood-brain barrier (BBB) disruption was associated with a pathologic angiogenesis in patients with intractable temporal lobe epilepsy (TLE) and in vivo models. This was confirmed by the overexpression of vascular endothelial growth factor (VEGF) in neurons and astrocytes and of its receptor vascular endothelial growth factor-2 (VEGF-R2) (or flk1) in endothelial cells. Using an original in vitro model, we showed that seizures were sufficient to activate the VEGF/VEGF-R2 system, which promotes vascularization and tight junction disassembly. Such a BBB dysfunction was shown to contribute to epileptogenesis. Therefore, we postulate that drugs that target the specific VEGF-R2 pathways involved in permeability are able to repair the BBB, and, therefore, could reduce epileptogenicity. Wiley Periodicals, Inc. © 2012 International League Against Epilepsy.

Vasileiou V.,Montpellier University | Granot J.,Open University of Israel | Piran T.,Hebrew University of Jerusalem | Amelino-Camelia G.,University of Rome La Sapienza
Nature Physics | Year: 2015

Wheeler's 'spacetime-foam'picture of quantum gravity (QG) suggests spacetime fuzziness (fluctuations leading to non-deterministic effects) at distances comparable to the Planck length, L Pl â ‰ 1.62 × 10 â '33 cm, the inverse (in natural units) of the Planck energy, E Pl â ‰ 1.22 × 10 19 GeV. The resulting non-deterministic motion of photons on the Planck scale is expected to produce energy-dependent stochastic fluctuations in their speed. Such a stochastic deviation from the well-measured speed of light at low photon energies, c, should be contrasted with the possibility of an energy-dependent systematic, deterministic deviation. Such a systematic deviation, on which observations by the Fermi satellite set Planck-scale limits for linear energy dependence, is more easily searched for than stochastic deviations. Here, for the first time, we place Planck-scale limits on the more generic spacetime-foam prediction of energy-dependent fuzziness in the speed of photons. Using high-energy observations from the Fermi Large Area Telescope (LAT) of gamma-ray burst GRB090510, we test a model in which photon speeds are distributed normally around c with a standard deviation proportional to the photon energy. We constrain the model's characteristic energy scale beyond the Planck scale at >2.8E Pl (>1.6E Pl), at 95% (99%) confidence. Our results set a benchmark constraint to be reckoned with by any QG model that features spacetime quantization. © 2015 Macmillan Publishers Limited. All rights reserved.

Prantzos N.,CNRS Paris Institute of Astrophysics | Boehm C.,LAPP | Bykov A.M.,RAS Ioffe Physical - Technical Institute | Diehl R.,Max Planck Institute for Extraterrestrial Physics | And 8 more authors.
Reviews of Modern Physics | Year: 2011

The first γ-ray line originating from outside the Solar System that was ever detected is the 511 keV emission from positron annihilation in the Galaxy. Despite 30 years of intense theoretical and observational investigation, the main sources of positrons have not been identified up to now. Observations in the 1990s with OSSE/CGRO (Oriented Scintillation Spectrometer Experiment on GRO satellite/Compton Gamma Ray Observatory) showed that the emission is strongly concentrated toward the Galactic bulge. In the 2000s, the spectrometer SPI aboard the European Space Agency's (ESA) International Gamma Ray Astrophysics Laboratory (INTEGRAL) allowed scientists to measure that emission across the entire Galaxy, revealing that the bulge-to-disk luminosity ratio is larger than observed at any other wavelength. This mapping prompted a number of novel explanations, including rather "exotic" ones (e.g., dark matter annihilation). However, conventional astrophysical sources, such as type Ia supernovae, microquasars, or x-ray binaries, are still plausible candidates for a large fraction of the observed total 511 keV emission of the bulge. A closer study of the subject reveals new layers of complexity, since positrons may propagate far away from their production sites, making it difficult to infer the underlying source distribution from the observed map of 511 keV emission. However, in contrast to the rather well-understood propagation of high-energy (>GeV) particles of Galactic cosmic rays, understanding the propagation of low-energy (∼MeV) positrons in the turbulent, magnetized interstellar medium still remains a formidable challenge. The spectral and imaging properties of the observed 511 keV emission are reviewed and candidate positron sources and models of positron propagation in the Galaxy are critically discussed. © 2011 American Physical Society.

Orliac M.J.,Montpellier University | Ducrocq S.,CNRS Institute of Paleoprimatology, Human Paleontoly: Evolution and Paleoenvironments
Geological Magazine | Year: 2012

Raoellidae are small fossil cetartiodactyls closely related to the Cetacea. Until now undisputable raoellid remains were reported only from the early Middle Eocene of the Indian Subcontinent, although this Indo-Pakistani endemism has been challenged by several recent works describing potential raoellids from Mongolia, Myanmar and China. In this contribution we address the question of raoellid taxonomic content and definition, through a revision of the dental features of the family. This work, which includes a revision of the putative raoellid material from outside Indo-Pakistan, is primarily based on a re-examination of 'suoid' specimens from Shanghuang (Middle Eocene, coastal China). Our results indicate that the Shanghuang material both substantiates the youngest and easternmost occurrence of Raoellidae and represents the only unquestionable record of raoellids outside the Indian Subcontinent at present. This significantly extends the geographical and chronological range of the family. The occurrence of a raoellid species in the Middle Eocene of coastal China implies that raoellids dispersed from the Indian Subcontinent to eastern Asia during Early or Middle Eocene time. This tempers classical hypotheses of Middle Eocene Indian endemism and eastern Asian provincialism. © Copyright Cambridge University Press 2011.

Regnier-Rosencher E.,University of Paris Descartes | Guillot B.,Montpellier University | Dupin N.,University of Paris Descartes
Journal of the American Academy of Dermatology | Year: 2013

Background: Treatment guidelines are lacking for classic Kaposi sarcoma. Objective: We sought to review the evidence on efficacy of treatments for classic Kaposi sarcoma. Methods: Articles published in English or French in MEDLINE, Trip, Cochrane Library, and Pascal databases from 1980 to December 2010 were screened. Studies reporting at least 5 patients treated for histologically confirmed classic Kaposi sarcoma were selected. Primary outcome was a decrease in the number or size of lesions or of lymphedema. We reviewed 26 articles matching the inclusion criteria for methodologic quality, classifying them according to World Health Organization criteria. Results: The percentage of patients with a 50% or greater decrease in lesions was 71% to 100% for pegylated liposomal doxorubicin, 58% to 90% for vinca-Alkaloids, 74% to 76% for etoposide, 93% to 100% for taxanes, 100% for gemcitabine, 97% for the combination of vinblastine and bleomycin, 71% to 100% for interferon alfa-2, 43% for thalidomide, and 12% for indinavir. For local treatments, a decrease of 50% or greater was achieved in 62% of lesions for intralesional vincristine, 50% to 90% for intralesional interferon alfa-2, 56% for imiquimod, and 25% for nicotine patches. A complete response was attained in 60% to 93% of lesions with radiotherapy. Limitations: Eligible trials were of poor quality. The lack of standardized classification of disease activity and clinical outcomes precluded the comparison of studies. Conclusion: The evidence for efficacy of any particular intervention is of low quality and does not support recommending any particular therapeutic strategy. Further studies are required and it will be important to standardize the assessment of disease activity and clinical response. © 2011 by the American Academy of Dermatology, Inc.

Droniou J.,Montpellier University
Networks and Heterogeneous Media | Year: 2010

We present different ways, coming from Finite Volume or Mixed Finite Element frameworks, to discretize convection terms in Hybrid Finite Volume, Mimetic Finite Difference and Mixed Finite Volume methods for elliptic equations. We compare them through several numerical tests, deducing some generic principles, depending on the situation, on the choice of an apropriate method and its parameters. We also present an adaptation to the Navier-Stokes equations, with a numerical tests in the case of the lid-driven cavity. © American Institute of Mathematical Sciences.

Brauer V.S.,University of Amsterdam | Brauer V.S.,University of Groningen | Brauer V.S.,Montpellier University | Stomp M.,University of Amsterdam | Huisman J.,University of Amsterdam
American Naturalist | Year: 2012

Resource competition theory predicts that the outcome of competition for two nutrients depends on the ratio at which these nutrients are supplied. Yet there is considerable debate whether nutrient ratios or absolute nutrient loads determine the species composition of phytoplankton and plant communities. Here we extend the classical resource competition model for two nutrients by including light as additional resource. Our results suggest the nutrientload hypothesis, which predicts that nutrient ratios determine the species composition in oligotrophic environments, whereas nutrient loads are decisive in eutrophic environments. The underlying mechanism is that nutrient enrichment shifts the species interactions from competition for nutrients to competition for light, which favors the dominance of superior light competitors overshadowing all other species. Intermediate nutrient loads can generate high biodiversity through a fine-grained patchwork of two-species and three-species coexistence equilibria. Depending on the species traits, however, competition for nutrients and light may also produce multiple alternative stable states, suppressing the predictability of the species composition. The nutrient-load hypothesis offers a solution for several discrepancies between classical resource competition theory and field observations, explains why eutrophication often leads to diversity loss, and provides a simple conceptual framework for patterns of biodiversity and community structure observed in nature. © 2012 by The University of Chicago.

Chabab M.,Cadi Ayyad University | Peyranere M.C.,Montpellier University | Rahili L.,Cadi Ayyad University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2014

Using the most recent results of CMS and ATLAS, we study the Higgs decays to γγ and Zγ in the scenario where the two CP-even Higgs predicted by the type II seesaw model (Higgs triplet models) are close to mass degenerate with a mass near 125 GeV. We analyze the effects of the Higgs potential parameters constrained by the full set of perturbative unitarity, boundedness from below as well as from precision electroweak measurements on these decay modes. Our analysis demonstrates that the observed excess in the diphoton Higgs decay channel can be interpreted in our scenario within a delineated region controlled by λ1 and λ4 coupling. We also find a deviation in the Higgs decay to Zγ with respect to the Standard Model prediction and the largest enhancement is found for a ratio RZγ of the order 1.6. Furthermore we show that consistency with current ATLAS data on the diphoton decay channel favors a light doubly charged Higgs with mass in the range 92-180 GeV. Finally, we find that the γγ and Zγ Higgs decay modes are generally correlated and the magnitude of correlation is sensitive to the sign of the λ1 parameter. © 2014 American Physical Society.

Huerga H.,Montpellier University
Journal of Acquired Immune Deficiency Syndromes | Year: 2016

INTRODUCTION:: Identifying gaps in HIV testing and treatment is essential to design specific strategies targeting those not accessing HIV services. We assessed the prevalence and factors associated with being HIV untested, unaware, untreated and virally unsuppressed in KwaZulu-Natal, South Africa. METHODS:: Cross-sectional population-based survey. People aged 15-59 years were eligible. Interviews, HIV testing and blood collection for antiretroviral drugs presence test, CD4, and viral load, were done at the participants’ home. RESULTS:: Of the 5,649 individuals included, 81.4% (95%CI:79.8-82.9) had previously been tested. HIV prevalence was 25.2%. HIV positivity awareness rate was 75.2% (95%CI:72.9-77.4). Of all unaware, 73.3% were people aged <35years and 68.7% were women. ART coverage was 75.0% (95%CI:72.0-77.8) among those eligible for treatment (CD4<350, PMTCT-B) and 53.1% (95%CI:50.4-55.7) among all HIV-positive. Viral load was <1,000cp/mL in 57.1% of all HIV positive. While 66.3% and 71.7% of people with viral load ≥1,000cp/mL were people aged <35years and women respectively, men had 4.4, 1.8, 1.6 and 1.7 times the odds of being untested, unaware, untreated and virally unsuppressed. In addition, people with more than 1 sexual partner had 1.3, 2.2 and 1.9 times the odds of being untested, unaware and untreated. CONCLUSIONS:: The majority of HIV-positive people unaware of their status, untreated and virally unsuppressed were individuals aged <35 years and women. However, men were disproportionately untested, unaware HIV positivity, untreated and virally unsuppressed. In this context, HIV testing and treatment should be prioritized to target young people and women, while novel strategies are necessary to reach men.This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND), which permits downloading and sharing the work provided it is properly cited. The work cannot be changed in any way or used commercially. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.

Neri I.,CNRS Charles Coulomb Laboratory | Kern N.,CNRS Charles Coulomb Laboratory | Parmeggiani A.,Montpellier University | Parmeggiani A.,French National Center for Scientific Research
Physical Review Letters | Year: 2011

We study the totally asymmetric simple exclusion process (TASEP) on complex networks, as a paradigmatic model for transport subject to excluded volume interactions. Building on TASEP phenomenology on a single segment and borrowing ideas from random networks we investigate the effect of connectivity on transport. In particular, we argue that the presence of disorder in the topology of vertices crucially modifies the transport features of a network: irregular networks involve homogeneous segments and have a bimodal distribution of edge densities, whereas regular networks are dominated by shocks leading to a unimodal density distribution. The proposed numerical approach of solving for mean-field transport on networks provides a general framework for studying TASEP on large networks, and is expected to generalize to other transport processes. © 2011 American Physical Society.

Chrysochoos A.,Montpellier University
Procedia IUTAM | Year: 2012

The cyclic behavior of materials often shows stabilized hysteretic responses. The present paper aims at highlighting the advantages of combining digital image correlation (DIC) and infrared thermography (IRT) to identify the energy nature of such hysteresis loops. Dissipative mechanisms are generally responsible for the mechanical energy lost in the stress-strain loop, reflecting irreversible material degradation. Thermodynamic analysis of the cyclic responses however revealed that such hysteresis areas may not only be induced by intrinsic dissipation but also by internal energy variations (stored energy) and/or by strong thermomechanical coupling effects associated with heat diffusion. From an experimental standpoint, kinematic data obtained by DIC techniques were used to estimate a stress-strain response and then compute the volume deformation energy within a hysteresis loop. Moreover, thermal images produced by an infrared camera were used to estimate the distribution of heat sources generated by the deformation. These sources may be due to dissipative and/or thermomechanical coupling effects. Several application examples were chosen to illustrate the diversity of mechanisms that induce hysteretic responses. © 2012 Published by Elsevier B.V.

Gounaris G.J.,Aristotle University of Thessaloniki | Renard F.M.,Montpellier University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

Studying e-e+→W-W+ at the one-loop electroweak order, we derive very accurate and simple expressions for the four helicity conserving amplitudes which dominate this process at high energies. The calculations are done in both the standard model and minimal supersymmetric standard model frameworks. Such expressions, called supersimple, nicely emphasize the dynamical contents of each framework. Numerical illustrations are presented, which show the accuracy of this description, and how it can be used for identifying possible additional new physics contributions, like, e.g., anomalous gauge couplings or a new Z ′ vector boson exchange. The procedure is useful even if only the standard model is visible at the future linear collider energies. © 2013 American Physical Society.

Neri I.,CNRS Charles Coulomb Laboratory | Kern N.,CNRS Charles Coulomb Laboratory | Parmeggiani A.,CNRS Charles Coulomb Laboratory | Parmeggiani A.,Montpellier University | Parmeggiani A.,French National Center for Scientific Research
Physical Review Letters | Year: 2013

We introduce the totally asymmetric simple exclusion process with Langmuir kinetics on a network as a microscopic model for active motor protein transport on the cytoskeleton, immersed in the diffusive cytoplasm. We discuss how the interplay between active transport along a network and infinite diffusion in a bulk reservoir leads to a heterogeneous matter distribution on various scales: we find three regimes for steady state transport, corresponding to the scale of the network, of individual segments, or local to sites. At low exchange rates strong density heterogeneities develop between different segments in the network. In this regime one has to consider the topological complexity of the whole network to describe transport. In contrast, at moderate exchange rates the transport through the network decouples, and the physics is determined by single segments and the local topology. At last, for very high exchange rates the homogeneous Langmuir process dominates the stationary state. We introduce effective rate diagrams for the network to identify these different regimes. Based on this method we develop an intuitive but generic picture of how the stationary state of excluded volume processes on complex networks can be understood in terms of the single-segment phase diagram. © 2013 American Physical Society.

Crouzet J.-F.,Montpellier University
Fuzzy Sets and Systems | Year: 2016

Fuzzy and inverse fuzzy transforms, introduced by I. Perfilieva, is an important tool for signal and image fuzzy representation. It led to several variants, as the natural least-squares minimization named fuzzy projection. We deal with this transform, proposing first to show its simplicity and its easy numerical implementation in any dimension of space. Secondly, we point out that a key parameter permits to control its numerical robustness. Thirdly, we show that this parameter also governs the stability of the representation by fuzzy projection, when choosing different partitions of the space. We conclude in discussing linear representation; especially triangular representation for signals and pyramidal representation for images. © 2016 Elsevier B.V.

Demoly P.,Montpellier University | Annunziata K.,Kantar Health | Gubba E.,Post Synaptic Ltd | Adamek L.,Glaxosmithkline
European Respiratory Review | Year: 2012

Although the main goal of asthma management guidelines is to achieve and maintain clinical control, reported levels of not well-controlled asthma remain high. The aim of this analysis was to compare the levels of asthma control and the associated impact on patients' health status in Europe in 2006, 2008 and 2010. An additional outcome was the comparison of the burden of asthma with diabetes. Data were obtained from the cross-sectional, self-reported, European National Health and Wellness Surveys conducted in France, Germany, Italy, Spain and the UK. Asthma control (Asthma Control Test TM; QualityMetric, Inc., Lincoln, RI, USA) and health status (Short Form (SF)-12 health survey and the Work Productivity Loss and Activity Impairment questionnaire) were assessed. In 2010, the proportion of treated asthma patients assessed as having not well-controlled asthma was 53.5%, compared with 56.6% and 55.0% in 2008 and 2006, respectively. A significant reduction in not well-controlled asthma was observed in Germany between 2006 (72.3%) and 2010 (62.5%; p50.005). Fluctuations in control levels were observed in other countries. For all surveys, having at least well-controlled asthma was associated with a significantly lower number of healthcare contacts in the previous 6 months, better mean¡SD SF-12 scores for the physical (data for 2010: not well controlled 39.9¡11.38, at least well-controlled 48.0¡9.89; p,0.001) and mental (data for 2010: not well-controlled 40.6¡10.95, at least well-controlled 45.0¡10.91; p,0.001) components, and significantly less impact on Work Productivity Loss and Activity Impairment. Asthma and diabetes were associated with a similar overall negative impact on health status. A substantial proportion of asthmatics remain not well-controlled across five European countries, resulting in a significant impact on health resources and patients' health status. The overall burden of asthma appears to be similar to that of diabetes. © ERS 2012.

Braza M.S.,French Institute of Health and Medical Research | Klein B.,French Institute of Health and Medical Research | Klein B.,Montpellier University Hospital Center | Klein B.,Montpellier University
British Journal of Haematology | Year: 2013

Gamma delta (γδ) Τ cells are non-conventional T lymphocyte effectors that can interact with and eradicate tumour cells. Several data demonstrate that these T cells, which are implicated in the first line of defence against pathogens, have anti-tumour activity against many cancers and suggest that γδ Τ cell-mediated immunotherapy is feasible and might induce objective tumour responses. Due to the importance of γδ Τ lymphocytes in the induction and control of immunity, a complete understanding of their biology is crucial for the development of a potent cancer immunotherapy. This review discusses recent advances in γδ Τ basic research and data from clinical trials on the use of γδ Τ cells in the treatment of different cancers. It analyses how this knowledge might be applied to develop new strategies for the clinical manipulation and the potentiation of γδ Τ lymphocyte activity in cancer immunotherapy. © 2012 Blackwell Publishing Ltd.

Ladmiral V.,University of Sheffield | Ladmiral V.,Charles Gerhardt Institute | Semsarilar M.,University of Sheffield | Semsarilar M.,Montpellier University | And 2 more authors.
Journal of the American Chemical Society | Year: 2013

Recent advances in polymer science are enabling substantial progress in nanobiotechnology, particularly in the design of new tools for enhanced understanding of cell biology and for smart drug delivery formulations. Herein, a range of novel galactosylated diblock copolymer nano-objects is prepared directly in concentrated aqueous solution via reversible addition-fragmentation chain transfer polymerization using polymerization-induced self-assembly. The resulting nanospheres, worm-like micelles, or vesicles interact in vitro with galectins as judged by a turbidity assay. In addition, galactosylated vesicles are highly biocompatible and allow intracellular delivery of an encapsulated molecular cargo. © 2013 American Chemical Society.

Berry V.,Montpellier University | Bininda-Emonds O.R.P.,Carl von Ossietzky University | Semple C.,University of Canterbury
Systematic Biology | Year: 2013

Supertree methods combine a collection of source trees into a single parent tree or supertree. For almost all such methods, the terminal taxa across the source trees have to be non-nested for the output supertree to make sense. Motivated by Page, the first supertree method for combining rooted source trees where the taxa can be hierarchically nested is called AncestralBuild. In addition to taxa labeling the leaves, this method allows the rooted source trees to have taxa labeling some of the interior nodes at a higher taxonomic level than their descendants (e.g., genera vs. species). However, the utility of AncestralBuild is somewhat restricted as it is mostly intended to decide if a collection of rooted source trees is compatible. If the initial collection is not compatible, then no tree is returned. To overcome this restriction, we introduce here the MultiLevelSupertree (MLS) supertree method whose input is the same as that for AncestralBuild, but which accommodates incompatibilities among rooted source trees using a MinCut-like procedure. We show that MLS has several desirable properties including the preservation of common subtrees among the source trees, the preservation of ancestral relationships whenever they are compatible, as well as running in polynomial time. Furthermore, application to a small test data set (the mammalian carnivore family Phocidae) indicates that the method correctly places nested taxa at different taxonomic levels (reflecting vertical signal), even in cases where the input trees harbor a significant level of conflict between their clades (i.e., in their horizontal signal). Nested taxa; Phocidae phylogeny; phylogenetics; supertree methods. © 2012 The Author(s).

Lehmann L.,UNIL Sorge | Rousset F.,Montpellier University
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2014

We survey the population genetic basis of social evolution, using a logically consistent set of arguments to cover a wide range of biological scenarios. We start by reconsidering Hamilton's (Hamilton 1964 J. Theoret. Biol. 7, 1-16 (doi:10.1016/0022-5193(64)90038-4)) results for selection on a social trait under the assumptions of additive gene action, weak selection and constant environment and demography. This yields a prediction for the direction of allele frequency change in terms of phenotypic costs and benefits and genealogical concepts of relatedness, which holds for any frequency of the trait in the population, and provides the foundation for further developments and extensions. We then allow for any type of gene interaction within and between individuals, strong selection and fluctuating environments and demography, which may depend on the evolving trait itself. We reach three conclusions pertaining to selection on social behaviours under broad conditions. (i) Selection can be understood by focusing on a one-generation change in mean allele frequency, a computation which underpins the utility of reproductive value weights; (ii) in large populations under the assumptions of additive gene action and weak selection, this change is of constant sign for any allele frequency and is predicted by a phenotypic selection gradient; (iii) under the assumptions of trait substitution sequences, such phenotypic selection gradients suffice to characterize long-term multidimensional stochastic evolution, with almost no knowledge about the genetic details underlying the coevolving traits. Having such simple results about the effect of selection regardless of population structure and type of social interactions can help to delineate the common features of distinct biological processes. Finally, we clarify some persistent divergences within social evolution theory, with respect to exactness, synergies, maximization, dynamic sufficiency and the role of genetic arguments. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Dulic V.,Institute Of Genetique Moleculaire | Dulic V.,French National Center for Scientific Research | Dulic V.,Montpellier University
Methods in Molecular Biology | Year: 2013

The senescence program is activated in response to diverse stress stimuli potentially compromising genetic stability and leads to an irreversible cell cycle arrest. The mTOR pathway plays a crucial role in the regulation of cell metabolism and cellular growth. The goal of this chapter is to present evidence linking these two processes, which have one common regulator-the tumor suppressor p53. While the role of mTOR in senescence is still controversial, recent papers have shed new light onto this issue. This review, far from being exhaustive given the complexity of the field, will hopefully stimulate further research in this domain, whose relevance for ageing is becoming increasingly documented. © Springer Science+Business Media New York 2013.

Clement Y.,Montpellier SupAgro | Clement Y.,Montpellier University | Arndt P.F.,Max Planck Institute for Molecular Genetics
Molecular Biology and Evolution | Year: 2013

Meiotic recombination is known to influence GC-content evolution in large regions of mammalian genomes by favoring the fixation of G and C alleles and increasing the rate of A/T to G/C substitutions. This process is known as GC-biased gene conversion (gBGC). Until recently, genome-wide measures of fine-scale recombination activity were unavailable in mice. Additionally, comparative studies focusing on mouse were limited as the closest organism with its genome fully sequenced was rat. Here, we make use of the recent mapping of double strand breaks (DSBs), the first step of meiotic recombination, in the mouse genome and of the sequencing of mouse closely related subspecies to analyze the fine-scale evolutionary signature of meiotic recombination on GC-content evolution in recombination hotspots, short regions that undergo extreme rates of recombination. We measure substitution rates around DSB hotspots and observe that gBGC is affecting a very short region (∼1 kbp) in length around these hotspots. Furthermore, we can infer that the locations of hotspots evolved rapidly during mouse evolution. © 2013 The Author.

Feist R.,Montpellier University | McNamara K.J.,University of Cambridge
Palaeontology | Year: 2013

In the early Late Devonian, terminal Frasnian proetid trilobites have previously only been known from Europe and North Africa. For the first time, a rich fauna of late Frasnian proetids is described from the Virgin Hills Formation, Canning Basin, Western Australia. Seventeen species in six genera are described, of which three are new: Rudybole gen. nov., Palpebralina gen. nov. and Canningbole gen. nov. A new subgenus, Chlupaciparia (Australoparia) subgen. nov. is also described. Fourteen of the species are new: Palpebralia initialis sp. nov., P. pustulata sp. nov., P. sp. nov. A, Rudybole depressa sp. nov., Palpebralina pseudopalpebralis sp. nov. (comprising the subspecies P. pseudopalpebralis pseudopalpebralis subsp. nov. and P. pseudopalpebralis ultima subsp. nov.), P. minor sp. nov., P. ocellifer sp. nov., Canningbole latimargo sp. nov., C. henwoodorum sp. nov., C. macromma sp. nov., Pteroparia extrema sp. nov., Chlupaciparia (Chlupaciparia) planiops sp. nov., Chlupaciparia (Australoparia) australis sp. nov. and C. (Australoparia) lata sp. nov. The subspecies Rudybole adorfensis angusta subsp. nov. is also described. The proetids range through conodont Zones 11-13b and terminate at the Upper Kellwasser Event, which marks the terminal Frasnian mass extinction event. Three of the six proetid lineages, Palpebralia, Canningbole and Pteroparia, show evolutionary trends of eye reduction. Two of the remaining lineages, Rudybole and Palpebralina, consist exclusively of blind taxa. The last, Chlupaciparia, also comprises forms with reduced eyes. The proetids show a stepped pattern of extinction during the late Frasnian, which correlate with two Kellwasser biocrises documented in European/North African Frasnian sections. The highest diversity preceded the Lower Kellwasser event that occurred at the end of conodont Zone 12 and saw the extinction of all species present in that zone. However, only one genus, Pteroparia, locally became extinct. A major higher-level taxonomic mass extinction at the top of Zone 13b initiated the Upper Kellwasser extinction event. This included extinction at the generic level, with all five remaining genera becoming extinct, and at the family level, with the loss of the Tropidocoryphidae. © The Palaeontological Association.

Stephan Y.,Montpellier University | Sutin A.R.,Florida State University | Terracciano A.,Florida State University
Brain, Behavior, and Immunity | Year: 2015

Subjective age, or how young or old individuals experience themselves to be, is related to a range of health-related outcomes in old age, including mortality risk. Little is known, however, about its association with markers of systemic inflammation. Using data from the Health and Retirement Study (HRS), the present study examined the relation between subjective age and C-reactive protein (CRP). Participants were 4120 older adults from the 2008 wave of the HRS who provided measures of subjective age, CRP, demographic variables, Body Mass Index (BMI), depression, smoking, physical activity and disease burden. Regression analyses revealed that a younger subjective age was related to lower CRP, controlling for demographic factors. This association was reduced by half but remained significant when health and behavioral covariates were adjusted for, suggesting that BMI, physical activity and disease burden may partially account for lower inflammation in individuals with a younger subjective age. Furthermore, a logistic regression revealed that feeling younger than one's age was associated with reduced risk of exceeding the clinical threshold of CRP, controlling for covariates. The present study provides the first evidence of an association between subjective age and systemic inflammation among older adults. It suggests that individuals' ratings of their subjective age may help identify individuals at greater risk for immune dysfunction related to morbidity and mortality. © 2014 Elsevier Inc.

Combe B.,Montpellier University
Clinical and Experimental Rheumatology | Year: 2010

The introduction of tumour necrosis factor (TNF) inhibitors for the treatment of rheumatoid arthritis (RA) represented a significant advance in the treatment of this debilitating disease, and led to dramatic changes in overall treatment goals and guidelines. Despite these advances, best practice use of TNF inhibitors in the clinical setting still needs to be determined. In particular, although all TNF inhibitors have standard, recommended doses that were determined in clinical trials, dose adjustments are often necessary in clinical practice to optimise therapeutic outcomes for individual patients. Dose escalation may be necessary in patients who experience disease flares, or because of insufficient initial efficacy or loss of efficacy over time, while dose tapering can be a response to adverse events, or if a patient achieves remission of disease. The amount of available evidence for managing dose adjustments for the currently available TNF inhibitors varies, and thus the strategies used with each are different. At present, although dose adjustments are common, data are insufficient for consensus guidelines to be recommended. © Copyright Clinical and Experimental Rheumatology 2010.

The Timétrine massif exposed west of the Pan-African suture zone in northeastern Mali belongs to the passive margin of the West African craton facing to the east intra-oceanic arc assemblages and 730. Ma old pre-collisional calc-alkaline plutons. The Timétrine lithologic succession includes from the base to the top Mesoproterozoic cratonic to passive margin formations overlain by deep-sea Fe-Mg schists. Submarine metabasalts and two ultramafic massifs of serpentinized mantle peridotites are inserted as olistoliths towards the top whereas turbidites of continental origin represent the younger unit. Field and petrological data have revealed a distinct metasedimentary sequence attached to the serpentinized peridotites. It essentially consists of impure carbonates, Fe jaspers and polymictic breccias containing altered blocks of mantle peridotites, most rocks being enriched in detrital chromite. This association is interpreted as reworked chemical and detrital sediments derived from the alteration of mafic-ultramafic rocks. It is argued that mantle exhumation above sea floor took place during the Neoproterozoic rifting and crustal thinning period under possible tropical conditions, as suggested by the large volume of silicified serpentinites. In spite of greenschist facies metamorphic overprint characterized by widespread Fe-rich blue amphiboles that are not diagnostic of high-pressure conditions, it is possible to reconstruct a former ocean-continent transition similar to that evidenced for the Mesozoic period, followed by the deposition of syn-to post rift terrigeneous turbidites roughly coeval with ocean spreading some time before 800. Ma. It is concluded that the serpentinite massifs were tectonically emplaced first in an extensional setting, then incorporated within deep-sea sediments as olistoliths and finally transported westward during late Neoproterozoic collisional tectonics onto the West African craton. © 2013 .

Pascal R.,Montpellier University | Pross A.,Ben - Gurion University of the Negev
Chemical Communications | Year: 2015

Bridging between the phenomenologically distinct biological and physical worlds has been a major scientific challenge since Boltzmann's probabilistic formulation of the second law of thermodynamics. In this review we summarize our recent theoretical attempts to bridge that divide through analysis of the thermodynamic-kinetic interplay in chemical processes and the manner in which that interplay impacts on material stability. Key findings are that the term 'stability' manifests two facets - time and energy - and that stability's time facet, expressed as persistence, is more general than its energy facet. That idea, together with the proposed existence of a logical law of nature, the persistence principle, leads to the mathematically-based insight that stability can come about through either Boltzmann's probabilistic considerations or Malthusian kinetics. Two mathematically-based forms of material persistence then lead directly to the physical likelihood of two material forms, animate and inanimate. Significantly, the incorporation of kinetic considerations into the stability concept appears to bring us closer to enabling two of the central theories in science - the second law of thermodynamics and Darwin's theory of evolution - to be reconciled within a single conceptual framework. © The Royal Society of Chemistry.

For many Mediterranean countries, karst aquifers offer an essential water resource. Their characteristics are mentioned as well as the specificity of Mediterranean karsts, determined by a particular climate and over all a recent complex geological history. The Messinian Crisis of Salinity (MCS), a major event which occurred 5.3 My ago, allowed the development of valleys and karst very lowly below present sea-level. Ignored by hydrogeologists and karstologists until the 90's, the MCS is now considered as a major period for developing karst conduits at great depth below the present sea level. The karst system of Chekka, Lebanon, and its large submarine springs are taken as an example to show the functioning of such coastal aquifers. The main consequences are here presented and analyzed in order to point out the absolute necessity for improving the knowledge on karst aquifers and regional hydrogeology. Karst submarine springs, typical of Mediterranean coasts, are considered as a non-conventional interesting resource, what will be discussed. The main issue is an efficient and sustainable management and protection of these groundwater resources in regions where the population density is highest and the economic activities are concentrated. Some new avenues of research and development are proposed.

Cascales-Minana B.,Montpellier University | Cascales-Minana B.,University of Liege
Review of Palaeobotany and Palynology | Year: 2016

This study aims to approximate an illustrative vision of the apparent temporal dynamics of land plant diversity during the terrestrialization process (i.e., the invasion of the land by plants). This problem has often been addressed through studying the Silurian-Devonian megafossil-based diversity patterns of land plants (embryophytes). However, the inclusion of the dispersed spore fossil record is essential for characterizing the first steps of this process (i.e., Eoembryophytic flora). Consequently, this new study includes both spore taxa and plant megafossils in order to discern the diversity trajectories from the first phases of early land plant diversification until the stabilization of early Carboniferous forests (i.e., Palaeophytic flora). The diversity patterns of the primary recognized plant lineages (i.e., Lycophyta and Euphyllophyta) have been also traced in order to discern the origin of the major fluctuations of plant megafossil-based diversity. Results reveal that while the dispersed spore diversity curve shows a sustained increase towards the end of the Devonian Period - with a first maximum towards the late Silurian - the megafossil embryophyte diversity curve is characterized by a set of sequential ascending peaks at the Pragian (Early Devonian), Givetian (Mid-Devonian), and Visean (Mississippian), with a single significant depletion in the Eifelian (Mid-Devonian). The comparative analysis of the lycophyte and euphyllophyte diversity patterns suggests that the substantial embryophytic diversity changes are driven by diversification within lineages rather than by the rhythm of the appearance of key morphological traits. This evidence (1) advocates for an intrinsic ecological control on the apparent changes in taxic richness and (2) implies that the observed plant diversity dynamics respond to the overlapping of the various expansion phases of the plant lineages involved. © 2015 Elsevier B.V.

Schneider M.,MPI of Biophysical Chemistry | Will C.L.,MPI of Biophysical Chemistry | Anokhina M.,MPI of Biophysical Chemistry | Tazi J.,Montpellier University | And 2 more authors.
Molecular Cell | Year: 2010

The first step in splicing of pre-mRNAs with long introns is exon definition, where U1 and U2 snRNPs bind at opposite ends of an exon. After exon definition, these snRNPs must form a complex across the upstream intron to allow splicing catalysis. Exon definition and conversion of cross-exon to cross-intron spliceosomal complexes are poorly understood. Here we demonstrate that, in addition to U1 and U2 snRNPs, cross-exon complexes contain U4, U5, and U6 (which form the tri-snRNP). Tri-snRNP docking involves the formation of U2/U6 helix II. This interaction is stabilized by a 5′ splice site (SS)-containing oligonucleotide, which can bind the tri-snRNP and convert the cross-exon complex into a cross-intron, B-like complex. Our data suggest that the switch from cross-exon to cross-intron complexes can occur directly when an exon-bound tri-snRNP interacts with an upstream 5′SS, without prior formation of a cross-intron A complex, revealing an alternative spliceosome assembly pathway. © 2010 Elsevier Inc. All rights reserved.

Gueydan F.,Montpellier University | Precigout J.,CNRS Institute of Earth Sciences | Montesi L.G.J.,University of Maryland University College
Tectonophysics | Year: 2014

Much debate exists concerning the strength distribution of the continental lithosphere, how it controls lithosphere-scale strain localization and hence enables plate tectonics. No rheological model proposed to date is comprehensive enough to describe both the weakness of plate boundary and rigid-like behaviour of plate interiors. Here we show that the duality of strength of the lithosphere corresponds to different stages of microstructural evolution. Geological constraints on lithospheric strength and large strain numerical experiments reveal that the development of layers containing weak minerals and the onset of grain boundary sliding upon grain size reduction in olivine cause strain localisation and reduce strength in the crust and subcontinental mantle, respectively. The positive feedback between weakening and strain localization leads to the progressive development of weak plate boundaries while plate interiors remain strong. © 2014 Elsevier B.V.

Vernant P.,Montpellier University | Reilinger R.,Massachusetts Institute of Technology | McClusky S.,Australian National University
Earth and Planetary Science Letters | Year: 2014

We develop a block model for the Aegean and surrounding areas, constrained by Global Positioning System (GPS), in order to investigate the degree of coupling on the Hellenic subduction interface (i.e., the fraction of the motion across the plate boundary accommodated by elastic strain accumulation). We use previously published models, and seismicity to define the geometry of the interface separating the down-going Nubian slab from the overriding Aegean. This model provides a good fit to the GPS observations; for the ~200,000 km2 Aegean block the wrms of the residual velocities is 1.4 mm/yr for 80 GPS velocity estimates, approximately the 95% level of the GPS velocity uncertainties. We investigate the degree of coupling on the seismically active plate interface, the Hellenic trench splay fault (believed to be the source of the 365 AD Great Crete Earthquake and Tsunami), and the Kephalonia transform fault by comparing the modeled GPS residual velocity field for a range of coupling values. The GPS observations are almost insensitive to coupling on the Kephalonia transform fault, because of the vertical dip of the fault that creates interseismic deformation only close to the fault where few GPS sites exist. The absence of resolvable shortening of the leading edge of the Aegean Plate precludes coupling of more than 0.2 (20% of the full Nubia-Aegean convergence rate) on the modeled plate interface. Because of the shallow dip of the plate interface and trench splay fault, and high rate of convergence, if these boundaries were fully coupled, high elastic strain rates would be expected to extend well into the overriding Aegean plate. Based on our preferred value for the degree of coupling (0.1), and assuming characteristic earthquake behavior, we estimate a recurrence time for great earthquakes with slip similar to that for the 365 Crete event of 5700-8300 yr, consistent with the absence of subsequent great earthquakes on this segment of the subduction zone. © 2013 Elsevier B.V.

Gross M.,Montpellier University
Applied Optics | Year: 2016

Heterodyne holography is a variant of phase-shifting holography in which the reference and signal arms are controlled by acousto-optic modulators. In this review paper, we will briefly describe the method and its properties, and we will illustrate its advantages in experimental applications. © 2015 Optical Society of America.

Mookherjee M.,Cornell University | Mainprice D.,Montpellier University
Geophysical Research Letters | Year: 2014

Using first principle simulations we calculated the elasticity of chlorite. At a density ρ~ 2.60 g cm-3, the elastic constant tensor reveals significant elastic anisotropy: VP ~27%, VS1 ~56%, and VS2 ~43%. The shear anisotropy is exceptionally large for chlorite and enhances upon compression. Upon compression, the shear elastic constant component C44 and C55 decreases, whereas C66 shear component stiffens. The softening in C44 and C55 is reflected in shear modulus, G, and the shear wave velocity, VS. Our results on elastic anisotropy at conditions relevant to the mantle wedge indicates that a 10-20 km layer of hydrated peridotite with serpentine and chlorite could account for the observed shear polarization anisotropy and associated large delay times of 1-2 s observed in some subduction zone settings. In addition, chlorite could also explain the low VP/VS ratios that have been observed in recent high-resolution seismological studies. Key Points First report of high pressure elasticity of chlorite Unusual shear wave anisotropy for chlorite Shear elastic anisotropy explains seismological observations in subduction zones ©2014. American Geophysical Union. All Rights Reserved.

Villeger S.,Montpellier University | Grenouillet G.,CNRS Biological Evolution and Diversity Laboratory | Brosse S.,CNRS Biological Evolution and Diversity Laboratory
Global Ecology and Biogeography | Year: 2014

Aim Human activities and the consequent extirpations of native species and introductions of non-native species have been modifying the composition of species assemblages throughout the world. These anthropogenic impacts have modified the richness of assemblages as well as the biological dissimilarity among them. However, while changes in taxonomic dissimilarity (i.e. accounting for species composition) have been assessed intensively during the last decade there are still few assessments of changes in functional dissimilarity (i.e. accounting for the diversity of biological traits). Here, we assess the temporal changes in both taxonomic and functional dissimilarities for freshwater fish assemblages across Europe. Location Western Palaearctic, 137 river basins. Methods The Jaccard index was used to quantify the changes in both taxonomic and functional dissimilarity. We then partitioned dissimilarity to extract its turnover component and measured the changes in the contribution of turnover to dissimilarity. Results Functional homogenization exceeded taxonomic homogenization sixfold. More importantly, we found only a moderate positive correlation between these changes. For instance, 40% of assemblages that experienced taxonomic differentiation were actually functionally homogenized. Taxonomic and functional homogenizations were stronger when the historical level of taxonomic dissimilarity among assemblages was high and when a high number of non-native species were introduced in the assemblages. Moreover, translocated species (i.e. non-native species originating from Europe) played a stronger role than exotic species (i.e. those coming from outside Europe) in this homogenization process, while extirpation did not play a significant role. Main conclusions Change in taxonomic diversity cannot be used to predict changes in functional diversity. In addition, as functional diversity has been proven to be a better indicator of ecosystem functioning and stability than taxonomic diversity, further studies are required to test the potential effects of functional homogenization at the local scale. © 2014 John Wiley & Sons Ltd.

Desarmenien M.G.,Montpellier University
Cellular and Molecular Neurobiology | Year: 2010

The adrenal medullary tissue contributes to maintain body homeostasis in reaction to stressful environmental changes via the release of catecholamines into the blood circulation in response to splanchnic nerve activation. Accordingly, chromaffin cell stimulus-secretion coupling undergoes temporally restricted periods of anatomo-functional remodeling in response to prevailing hormonal requirements of the organism. The postnatal development of the adrenal medulla and response to stress are remarkable physiological situations in which the stimulus-secretion coupling is critically affected. Catecholamine secretion from rat chromaffin cells is under a dual control involving an incoming initial command arising from the sympathetic nervous system that releases acetylcholine at the splanchnic nerve terminal-chromaffin cell synapses and a local gap junction-mediated intercellular communication. Interestingly, these two communication pathways are functionally interconnected within the gland and exhibit coordinated plasticity mechanisms. This article reviews the physiological and molecular evidence that the adrenal medullary tissue displays anatomical and functional adaptative remodeling of cell-cell communications upon physiological (postnatal development) and/or physiopathological (stress) situations associated with specific needs in circulating catecholamine levels. © 2010 Springer Science+Business Media, LLC.

Orliac M.J.,Montpellier University
Journal of Systematic Palaeontology | Year: 2013

The morphology of the petrosal is often employed in mammalian systematics, yet this bone has not been described in detail for a comparative sample of extinct members of Suoidea (the clade encompassing pigs, peccaries and their extinct relatives), a total clade that represents one of the major divisions within Artiodactyla. Here, the petrosal osteology of fossil Suoidea ranging from their early representatives (Late Eocene) up to Late Miocene is described. A sample of petrosal specimens documenting eight genera from the four suoid families (Suidae, Tayassuidae, Sanitheriidae and Palaeochoeridae) has been collected from in situ mechanical preparation, CT-based reconstruction or identification of isolated petrosals. The diagnostic significance of petrosal characters for suoid systematics is assessed by the inclusion of the new petrosals data in a phylogenetic analysis. As in other mammal groups, petrosal characters are shown to be of primary phylogenetic interest. The monophyly of the included families and subfamilies shown by craniodental and postcranial characters is supported by petrosal characters, and the problematic New World suoid Perchoerus is interpreted as the first offshoot of the Suoidea clade. This work allows definition of Suoidea on the basis of petrosal morphological characters and reveals the shaping over time of the peculiar petrosal morphology observed in extant suoids, notably the drastic reduction of the mastoid of this amastoidean group, convergently present in hippos. © 2013 Copyright Taylor and Francis Group, LLC.

Font Y.,University of Nice Sophia Antipolis | Segovia M.,National Polytechnic School of Ecuador | Vaca S.,National Polytechnic School of Ecuador | Theunissen T.,Montpellier University
Geophysical Journal International | Year: 2013

To improve earthquake location, we create a 3-D a priori P-wave velocity model (3-DVM) that approximates the large velocity variations of the Ecuadorian subduction system. The 3-DVM is constructed from the integration of geophysical and geological data that depend on the structural geometry and velocity properties of the crust and the upper mantle. In addition, specific station selection is carried out to compensate for the high station density on the Andean Chain. 3-D synthetic experiments are then designed to evaluate the network capacity to recover the event position using only P arrivals and the MAXI technique. Three synthetic earthquake location experiments are proposed: (1) noise-free and (2) noisy arrivals used in the 3-DVM, and (3) noise-free arrivals used in a 1-DVM. Synthetic results indicate that, under the best conditions (exact arrival data set and 3-DVM), the spatiotemporal configuration of the Ecuadorian network can accurately locate 70 per cent of events in the frontal part of the subduction zone (average azimuthal gap is 289° ± 44°). Noisy P arrivals (up to ± 0.3 s) can accurately located 50 per cent of earthquakes. Processing earthquake location within a 1-DVM almost never allows accurate hypocentre position for offshore earthquakes (15 per cent), which highlights the role of using a 3-DVM in subduction zone. For the application to real data, the seismicity distribution from the 3-D-MAXI catalogue is also compared to the determinations obtained in a 1-D-layered VM. In addition to good-quality location uncertainties, the clustering and the depth distribution confirm the 3-D-MAXI catalogue reliability. The pattern of the seismicity distribution (a 13 yr record during the inter-seismic period of the seismic cycle) is compared to the pattern of rupture zone and asperity of the MW = 7.9 1942 and the MW = 7.7 1958 events (the MW = 8.8 1906 asperity patch is not defined). We observe that the nucleation of 1942, 1958 and 1906 events coincides with areas of positive Simple Bouguer anomalies and areas where marine terraces are still preserved on the coastal morphology. From north to south: (1) the 1958 rupture zone is almost aseismic and is attributed to a zone of high coupling; (2) south of the Galera alignment (perpendicular to the trench), the 1942 rupture zone presents moderate seismicity, deeper on the seismogenic interplate zone, and abutting on the Jama cluster (to the south). This cluster is facing the Cabo Pasado cap and positive Bouguer anomalies on the overriding margin.We suspect that this cluster reflects a zone of local asperity (partial coupling). South of the Jama cluster, the spherical aseismic zone in the Bahia area is interpreted as having a low seismic coupling (steady creep motion or slow slip events). We suspect that the site that generated the three M > 7 events (1896, 1956 and 1998) correspond to a small patch of strong coupling. To the south, in the Manta-Puerto Lopez zone, the seismicity is mainly organized in earthquake swarms (1998, 2002, 2005). Although slow slip events have been observed in the area (Vallée et al. submitted), we infer from the coastline shape, the marine terraces and the high positive Bouguer anomalies that the seismicity here might reveal a significant amount of seismic coupling. © The Authors 2013. Published by Oxford University Press on behalf of The Royal Astronomical Society.

Ducournau R.,Montpellier University
Software - Practice and Experience | Year: 2011

Late binding and subtyping create run-time overhead for object-oriented languages. Dynamic typing and multiple inheritance create even more overhead. Static typing and single inheritance lead to two major invariants, of reference and position, that make the implementation as efficient as possible. Coloring is a technique that preserves these invariants for dynamic typing or multiple inheritance at minimal spatial cost. Coloring has been independently proposed for method invocation under the name of selector coloring, for subtype tests under the name of pack encoding, and for attribute access and object layout. This paper reviews a number of uses of coloring for optimizing object-oriented programming, generalizes them, and specifies several variations, such as bidirectional and n-directional coloring. Coloring is NP-hard, hence compilers that use it depend on heuristics. The paper describes two families of heuristics and presents some experimental results which indicate that coloring is both efficient and tractable and that bidirectional coloring gives the best results. Copyright © 2010 John Wiley & Sons, Ltd.

Renaud S.,CNRS Biometry and Evolutionary Biology Laboratory | Alibert P.,University of Burgundy | Auffray J.-C.,Montpellier University
BMC Evolutionary Biology | Year: 2012

Abstract. Background: Hybridization is often seen as a process dampening phenotypic differences accumulated between diverging evolutionary units. For a complex trait comprising several relatively independent modules, hybridization may however simply generate new phenotypes, by combining into a new mosaic modules inherited from each parental groups and parts intermediate with respect to the parental groups. We tested this hypothesis by studying mandible size and shape in a set of first and second generation hybrids resulting from inbred wild-derived laboratory strains documenting two subspecies of house mice, Musmusculus domesticus and Musmusculus musculus. Phenotypic variation of the mandible was divided into nested partitions of developmental, evolutionary and functional modules. Results: The size and shape of the modules were differently influenced by hybridization. Some modules seemed to be the result of typical additive effects with hybrids intermediate between parents, some displayed a pattern expected in the case of monogenic dominance, whereas in other modules, hybrids were transgressive. The result is interpreted as the production of novel mandible morphologies. Beyond this modularity, modules in functional interaction tended to display significant covariations. Conclusions: Modularity emerges as a source of novel morphological variation by its simple potential to combine different parts of the parental phenotypes into a novel offspring mosaic of modules. This effect is partly counterbalanced by bone remodeling insuring an integration of the mosaic mandible into a functional ensemble, adding a non-genetic component to the production of transgressive phenotypes in hybrids. © 2012 Renaud et al.; licensee BioMed Central Ltd.

Cairns A.B.,University of Oxford | Catafesta J.,Charles Gerhardt Institute | Catafesta J.,CNRS Charles Coulomb Laboratory | Levelut C.,CNRS Charles Coulomb Laboratory | And 7 more authors.
Nature Materials | Year: 2013

The counterintuitive phenomenon of negative linear compressibility (NLC) is a highly desirable but rare property exploitable in the development of artificial muscles, actuators and next-generation pressure sensors. In all cases, material performance is directly related to the magnitude of intrinsic NLC response. Here we show the molecular framework material zinc(II) dicyanoaurate(I), Zn[Au(CN) 2 ] 2, exhibits the most extreme and persistent NLC behaviour yet reported: under increasing hydrostatic pressure its crystal structure expands in one direction at a rate that is an order of magnitude greater than both the typical contraction observed for common engineering materials and also the anomalous expansion in established NLC candidates. This extreme behaviour arises from the honeycomb-like structure of Zn[Au(CN) 2 ] 2 coupling volume reduction to uniaxial expansion, and helical Au...Au 'aurophilic' interactions accommodating abnormally large linear strains by functioning as supramolecular springs. © 2013 Macmillan Publishers Limited. All rights reserved.

Gounaris G.J.,Aristotle University of Thessaloniki | Renard F.M.,Montpellier University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

We study the process e-e+→γH, where H represents HSM, h0, or H0. This process occurs at the one loop level in the standard model or in the minimal supersymmetric standard model (MSSM). We establish supersimple (sim) high energy expressions for all helicity amplitudes of this process, and we identify their level of accuracy for describing the various polarized and unpolarized observables, and for distinguishing SM from MSSM or another beyond the standard model. We pay special attention to transverse e± polarization and azimuthal dependencies induced by the imaginary parts of the amplitudes, which are relatively important in this process. © 2015 American Physical Society.

Mooers A.,Simon Fraser University | Gascuel O.,Montpellier University | Stadler T.,Universitatstrasse 16 | Li H.,University of Canterbury | Steel M.,University of Canterbury
Systematic Biology | Year: 2012

Diversification is nested, and early models suggested this could lead to a great deal of evolutionary redundancy in the Tree of Life. This result is based on a particular set of branch lengths produced by the common coalescent, where pendant branches leading to tips can be very short compared with branches deeper in the tree. Here, we analyze alternative and more realistic Yule and birth-death models. We show how censoring at the present both makes average branches one half what we might expect and makes pendant and interior branches roughly equal in length. Although dependent on whether we condition on the size of the tree, its age, or both, these results hold both for the Yule model and for birth-death models with moderate extinction. Importantly, the rough equivalency in interior and exterior branch lengths means that the loss of evolutionary history with loss of species can be roughly linear. Under these models, the Tree of Life may offer limited redundancy in the face of ongoing species loss. © 2011 The Author(s).

Ducournau R.,Montpellier University | Privat J.,Dep. dInformatique
Science of Computer Programming | Year: 2011

Inheritance provides object-oriented programming with much of its great reusability power. When inheritance is single, its specifications are simple and everybody roughly agrees on them. In contrast, multiple inheritance yields ambiguities that have prompted long-standing debates, and no two languages agree on its specifications. In this paper, we present a semantics of multiple inheritance based on metamodeling. A metamodel is proposed which distinguishes the "identity" of properties from their "values" or "implementations". It yields a clear separation between syntactic and semantic conflicts. The former can be solved in any language at the expense of a common syntactic construct, namely full name qualification. However, semantic conflicts require a programmer's decision, and the programming language must help the programmer to some extent. This paper surveys the approach based on linearizations, which has been studied in depth, and proposes some extensions. As it turns out that only static typing takes full advantage of the metamodel, the interaction between multiple inheritance and static typing is also considered, especially in the context of virtual types. The solutions proposed by the various languages with multiple inheritance are compared with the metamodel results. Throughout the paper, difficulties encountered under the open-world assumption are stressed. © 2010 Elsevier B.V. All rights reserved.

Gautier M.,Montpellier SupAgro | Gautier M.,Institute Of Biologie Computationnelle | Vitalis R.,Montpellier SupAgro | Vitalis R.,Institute Of Biologie Computationnelle | Vitalis R.,Montpellier University
Molecular Biology and Evolution | Year: 2013

The recent development of high-throughput genotyping technologies has revolutionized the collection of data in a wide range of both model and nonmodel species. These data generally contain huge amounts of information about the demographic history of populations. In this study, we introduce a new method to estimate divergence times on a diffusion time scale from large single-nucleotide polymorphism (SNP) data sets, conditionally on a population history that is represented as a tree. We further assume that all the observed polymorphisms originate from the most ancestral (root) population; that is, we neglect mutations that occur after the split of the most ancestral population. This method relies on a hierarchical Bayesian model, based on Kimura's time-dependent diffusion approximation of genetic drift. We implemented a Metropolis-Hastings within Gibbs sampler to estimate the posterior distribution of the parameters of interest in this model, which we refer to as the Kimura model. Evaluating the Kimura model on simulated population histories, we found that it provides accurate estimates of divergence time. Assessing model fit using the deviance information criterion (DIC) proved efficient for retrieving the correct tree topology among a set of competing histories. We show that this procedure is robust to low-to-moderate gene flow, as well as to ascertainment bias, providing that the most distantly related populations are represented in the discovery panel. As an illustrative example, we finally analyzed published human data consisting in genotypes for 452,198 SNPs from individuals belonging to four populations worldwide. Our results suggest that the Kimura model may be helpful to characterize the demographic history of differentiated populations, using genome-wide allele frequency data. © 2012 The Author.

Lartillot N.,University of Montreal | Lartillot N.,Montpellier University
Molecular Biology and Evolution | Year: 2013

GC-biased gene conversion (gBGC) is a major evolutionary force shaping genomic nucleotide landscapes, distorting the estimation of the strength of selection, and having potentially deleterious effects on genome-wide fitness. Yet, a global quantitative picture, at large evolutionary scale, of the relative strength of gBGC compared with selection and random drift is still lacking. Furthermore, owing to its dependence on the local recombination rate, gBGC results in modulations of the substitution patterns along genomes and across time which, if correctly interpreted, may yield quantitative insights into the long-term evolutionary dynamics of recombination landscapes. Deriving a model of the substitution process at putatively neutral nucleotide positions from population-genetics arguments, and accounting for among-lineage and among-gene effects, we propose a reconstruction of the variation in gBGC intensity at the scale of placental mammals, and of its scaling with body-size and karyotypic traits. Our results are compatible with a simple population genetics model relating gBGC to effective population size and recombination rate. In addition, among-gene variation and phylogenetic patterns of exon-specific levels of gBGC reveal the presence of rugged recombination landscapes, and suggest that short-lived recombination hot-spots are a general feature of placentals. Across placental mammals, variation in gBGC strength spans two orders of magnitude, at its lowest in apes, strongest in lagomorphs, microbats or tenrecs, and near or above the nearly neutral threshold in most other lineages. Combined with among-gene variation, such high levels of biased gene conversion are likely to significantly impact midly selected positions, and to represent a substantial mutation load. Altogether, our analysis suggests a more important role of gBGC in placental genome evolution, compared with what could have been anticipated from studies conducted in anthropoid primates. © 2012 The Author.

Nguyen-Chi M.,Montpellier University | Morello D.,University Paul Sabatier
Reproduction | Year: 2011

Changes in mRNA translation and degradation represent post-transcriptional processes operating during gametogenesis and early embryogenesis to ensure regulated protein synthesis. Numerous mRNA-binding proteins (RBPs) have been described in multiple animal models that contribute to the control of mRNA translation and decay during oogenesis and spermatogenesis. An emerging view from studies performed in germ cells and somatic cells is that RBPs associate with their target mRNAs in RNA-protein (or ribonucleoprotein) complexes (mRNPs) that assemble in various cytoplasmic RNA granules that communicate with the translation machinery and control mRNA storage, triage, and degradation. In comparison with Xenopus, Caenorhabditis elegans, or Drosophila, the composition and role of cytoplasmic RNA-containing granules in mammalian germ cells are still poorly understood. However, regained interest for these structures has emerged with the recent discovery of their role in small RNA synthesis and transposon silencing through DNA methylation. In this review, we will briefly summarize our current knowledge on cytoplasmic RNA granules in murine germ cells and describe the role of some of the RBPs they contain in regulating mRNA metabolism and small RNA processing during gametogenesis. © 2011 Society for Reproduction and Fertility.

Albuquerque R.M.,University of Sao Paulo | Narison S.,Montpellier University | Nielsen M.,University of Sao Paulo
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2010

We extract directly (for the first time) the charmed (C = 1) and bottom (B = - 1) heavy-baryons (spin 1/2 and 3/2) mass-splittings due to SU (3) breaking using double ratios of QCD spectral sum rules (QSSR) in full QCD, which are less sensitive to the exact value and definition of the heavy quark mass, to the perturbative radiative corrections and to the QCD continuum contributions than the simple ratios commonly used for determining the heavy baryon masses. Noticing that most of the mass-splittings are mainly controlled by the ratio κ ≡ 〈 over(s, ̄) s 〉 / 〈 over(d, ̄) d 〉 of the condensate, we extract this ratio, by allowing 1σ deviation from the observed masses of the Ξ c, b and of the Ω c. We obtain: κ = 0.74 (3), which improves the existing estimates: κ = 0.70 (10) from light hadrons. Using this value, we deduce M Ωb = 6078.5 (27.4) MeV which agrees with the recent CDF data but disagrees by 2.4σ with the one from D0. Predictions of the Ξ Q ′ and of the spectra of spin 3/2 baryons containing one or two strange quark are given in Table 2. Predictions of the hyperfine splittings Ω Q * - Ω Q and Ξ Q * - Ξ Q are also given in Table 3. Starting for a general choice of the interpolating currents for the spin 1/2 baryons, our analysis favours the optimal value of the mixing angle b ≃ (- 1 / 5 - 0) found from light and non-strange heavy baryons. © 2010 Elsevier B.V. All rights reserved.

Mouquet N.,Montpellier University | Gravel D.,University of Quebec at Rimouski | Massol F.,IRSTEA | Massol F.,CNRS Center of Evolutionary and Functional Ecology | Calcagno V.,CNRS Sophia Agrobiotech Institute
Ecology Letters | Year: 2013

Keystone species are defined as having disproportionate importance in their community. This concept has proved useful and is now often used in conservation ecology. Here, we introduce the concept of keystone communities (and ecosystems) within metacommunities (and metaecosystems). We define keystone and burden communities as communities with impacts disproportionately large (positive or negative respectively) relative to their weight in the metacommunity. We show how a simple metric, based on the effects of single-community removals, can characterise communities along a 'keystoneness' axis. We illustrate the usefulness of this approach with examples from two different theoretical models. We further distinguish environmental heterogeneity from species trait heterogeneity as determinants of keystoneness. We suggest that the concept of keystone communities/ecosystems will be highly beneficial, not only as a fundamental step towards understanding species interactions in a spatial context, but also as a tool for the management of disturbed landscapes. © 2012 Blackwell Publishing Ltd/CNRS.

Xu J.,Northeastern University | Gattacceca F.,Northeastern University | Gattacceca F.,Montpellier University | Amiji M.,Northeastern University
Molecular Pharmaceutics | Year: 2013

The objective of this study was to evaluate qualitative and quantitative biodistribution of epidermal growth factor receptor (EGFR)-targeted thiolated type B gelatin nanoparticles in vivo in subcutaneous human pancreatic adenocarcinoma (Panc-1) bearing female SCID Beige mice. EGFR-targeted nanoparticles showed preferential and sustained accumulation in the tumor mass, especially at early time points. Higher blood concentrations and higher tumor accumulations were observed with PEG-modified and EGFR-targeted nanoparticles during the study (AUClast: 17.38 and 19.56%ID/mL·h in blood, 187 and 322%ID/g·h in tumor for PEG-modified and EGFR-targeted nanoparticles, respectively), as compared to control, unmodified particles (AUClast: 10.71%ID/mL·h in blood and 138%ID/g·h in tumor). EGFR-targeted nanoparticles displayed almost twice tumor targeting efficiency than either PEG-modified or the unmodified nanoparticles, highlighting the efficacy of the active targeting strategy. In conclusion, this study shows that EGFR-targeted and PEG-modified nanoparticles were suitable vehicles for specific systemic delivery in subcutaneous Panc-1 tumor xenograft models. © 2013 American Chemical Society.

Calderon M.A.,Imperial College London | Casale T.B.,Creighton University | Nelson H.S.,National Jewish Health | Demoly P.,Montpellier University
Journal of Allergy and Clinical Immunology | Year: 2013

Background: According to meta-analyses and reviews, subcutaneous allergen immunotherapy (SCIT) and sublingual allergen immunotherapy (SLIT) are beneficial in patients with allergic rhinitis (AR) and allergic asthma (AA) induced by house dust mites (HDMs). However, the reported effect sizes have varied greatly from one study to another. Objective: We sought to perform an evidence-based medicine assessment of commercially available SCIT and SLIT formulations in patients with HDM-induced AA and HDM-induced AR. Methods: We searched for double-blind, placebo-controlled randomized clinical trials and analyzed study designs, doses, regimens, patient-reported outcomes, safety reporting, and compliance. Results: Forty-four studies met our inclusion criteria. Some studies tested both SLIT and SCIT or scored both AA and AR outcomes; therefore we reviewed 35 treatment arms in patients with AA (20 for SCIT and 15 for SLIT) and 23 treatment arms in patients with AR (7 for SCIT and 16 for SLIT). The treatment duration ranged from 6 weeks to 3 years. For SCIT, the dose of Der p 1 major allergen (when reported) ranged from 7 to 30 μg for maintenance doses and 60 to 420 μg for cumulative doses. For SLIT, the doses of Der p 1 (when reported) were 0.8 to 70 μg for maintenance doses and 60 to 23,695 μg for cumulative doses. Safety data were often absent or poorly reported. A statistically significant active versus placebo symptom score was observed more frequently for SCIT than for SLIT. Conclusion: There is no consensus on basic treatment parameters (eg, dose and duration) in HDM SCIT and SLIT. There is an urgent need for rigorous, long-term, double-blind, placebo-controlled randomized clinical trials with an efficacy criterion that reflects the particular features of HDM-induced allergic disease. © 2013 American Academy of Allergy, Asthma & Immunology.

Dimeglio A.,Montpellier University | Canavese F.,Center Hospitalier University Estaing
Orthopedic Clinics of North America | Year: 2011

Imaging in Legg-Calvé-Perthes disease should help assess the severity and the stage of the disease, detect severe forms earlier, and provide guidance to therapy. However, due to the complexity of the disease, not all examinations can be performed at the same time with the same goals. The scope of this work is to provide an overview of all imaging techniques available today, and to help understand when to use a particular examination. Advantages and limitations of plain radiographs, bone scintigraphy, magnetic resonance imaging, arthrography, computed tomography, and ultrasonography are identified. © 2011 Elsevier Inc.

Chiriac A.M.,Allergy Unit | Demoly P.,Allergy Unit | Demoly P.,Montpellier University
Current Opinion in Allergy and Clinical Immunology | Year: 2013

PURPOSE OF REVIEW: The multiple drug hypersensitivity syndrome (MDH) is a distinct clinical entity, different from cross-reactivity and flare-up reactions. Following its initial description in 1989 by Sullivan et al., several authors have addressed the issues surrounding this peculiar form of drug hypersensitivity. Whether this syndrome is single or can be further classified in several entities is still a matter of debate. RECENT FINDINGS: Case reports, case series or studies involving large populations on MDH are few. The use of this term in the literature is heterogeneous, and the definitions variable. Given the major advances in the study of drug hypersensitivities in general, and ongoing research regarding severe cutaneous adverse reactions in particular, careful study of the subgroup of patients with demonstrated immunological basis of MDH has enabled the generation of possible pathogenetic hypotheses. Together with the studies (despite their limitations) to estimate the prevalence of this syndrome in adult and paediatric patients these emerging data need confirmation through larger studies with well defined populations. SUMMARY: Bringing together the experience of groups involved in the field of drug allergy should help to move knowledge regarding this peculiar form of drug hypersensitivity forward. © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Macke E.,Montpellier University
Proceedings. Biological sciences / The Royal Society | Year: 2011

Haplodiploid species display extraordinary sex ratios. However, a differential investment in male and female offspring might also be achieved by a differential provisioning of eggs, as observed in birds and lizards. We investigated this hypothesis in the haplodiploid spider mite Tetranychus urticae, which displays highly female-biased sex ratios. We show that egg size significantly determines not only larval size, juvenile survival and adult size, but also fertilization probability, as in marine invertebrates with external fertilization, so that female (fertilized) eggs are significantly larger than male (unfertilized) eggs. Moreover, females with on average larger eggs before fertilization produce a more female-biased sex ratio afterwards. Egg size thus mediates sex-specific egg provisioning, sex and offspring sex ratio. Finally, sex-specific egg provisioning has another major consequence: male eggs produced by mated mothers are smaller than male eggs produced by virgins, and this size difference persists in adults. Virgin females might thus have a (male) fitness advantage over mated females.

Schuettengruber B.,CNR Institute of Neuroscience | Martinez A.-M.,CNR Institute of Neuroscience | Martinez A.-M.,Montpellier University | Iovino N.,CNR Institute of Neuroscience | Cavalli G.,CNR Institute of Neuroscience
Nature Reviews Molecular Cell Biology | Year: 2011

Cellular memory is provided by two counteracting groups of chromatin proteins termed Trithorax group (TrxG) and Polycomb group (PcG) proteins. TrxG proteins activate transcription and are perhaps best known because of the involvement of the TrxG protein MLL in leukaemia. However, in terms of molecular analysis, they have lived in the shadow of their more famous counterparts, the PcG proteins. Recent advances have improved our understanding of TrxG protein function and demonstrated that the heterogeneous group of TrxG proteins is of critical importance in the epigenetic regulation of the cell cycle, senescence, DNA damage and stem cell biology. © 2011 Macmillan Publishers Limited. All rights reserved.

Various bacteria live exclusively within arthropod cells and collectively act as an important driver of arthropod evolutionary ecology. Whereas rampant intra-generic DNA transfers were recently shown to have a pivotal role in the evolution of the most common of these endosymbionts, Wolbachia, the present study show that inter-generic DNA transfers also commonly take place, constituting a potent source of rapid genomic change. Bioinformatic, molecular and phylogenetic data provide evidence that a selfish genetic element, the insertion sequence ISRpe1, is widespread in the Wolbachia, Cardinium and Rickettsia endosymbionts and experiences recent (and likely ongoing) transfers over long evolutionary distances. Although many ISRpe1 copies were clearly expanding and leading to rapid endosymbiont diversification, degraded copies are also frequently found, constituting an unusual genomic fossil record suggestive of ancient ISRpe1 expansions. Overall, the present data highlight how ecological connections within the arthropod intracellular environment facilitate lateral DNA transfers between distantly related bacterial lineages. © 2013 Macmillan Publishers Limited All rights reserved.

Di Pietro D.A.,Montpellier University | Ern A.,University Paris Est Creteil
Computer Methods in Applied Mechanics and Engineering | Year: 2015

We devise an arbitrary-order locking-free method for linear elasticity. The method relies on a pure-displacement (primal) formulation and leads to a symmetric, positive definite system matrix with compact stencil. The degrees of freedom are vector-valued polynomials of arbitrary order k≥1 on the mesh faces, so that in three space dimensions, the lowest-order scheme only requires 9 degrees of freedom per mesh face. The method can be deployed on general polyhedral meshes. The key idea is to reconstruct the symmetric gradient and divergence inside each mesh cell in terms of the degrees of freedom by solving inexpensive local problems. The discrete problem is assembled cell-wise using these operators and a high-order stabilization bilinear form. Locking-free error estimates are derived for the energy norm and for the L2-norm of the displacement, with optimal convergence rates of order (k+1) and (k+2), respectively, for smooth solutions on general meshes. The theoretical results are confirmed numerically, and the CPU cost is evaluated on both standard and polygonal meshes. © 2014 Elsevier B.V.

Raison-Peyron N.,Montpellier University
European Journal of Dermatology | Year: 2013

Cutaneous adverse drug reactions present as many different clinical symptoms which may be induced by triggers other than drugs. This review focuses on the non-drug causes of fixed "drug" eruptions, acute generalized erythematous pustulosis (AGEP), "drug" reactions with eosinophilia and systemic symptoms (DRESS) and Stevens-Johnson syndrome/toxic epidermal necrolysis (TEN), which may be induced by foods, xenobiotics, venoms etc.

Bang-Jensen Jo.,University of Southern Denmark | Bessy S.,Montpellier University
Theoretical Computer Science | Year: 2014

We consider the problem of deciding whether a given network with integer capacities has two feasible flows x and y with prescribed balance vectors such that the arcs that carry flow in x are arc-disjoint from the arcs that carry flow in y. This generalizes a number of well-studied problems such as the existence of arc-disjoint out-branchings Bs+, Bt+ where the roots s, t may be the same vertex, existence of arc-disjoint spanning subdigraphs D1, D2 with prescribed degree sequences in a digraph (e.g. arc-disjoint cycle factors), the weak-2-linkage problem, the number partitioning problem, etc. Hence the problem is NP-complete in general. We show that the problem remains hard even for very restricted cases such as two arc-disjoint (s,t)-flows each of value 2 in a network with capacities 1 and 2 on the arcs. On the positive side, we prove that the above problem is polynomially solvable if the network is acyclic and the arc capacities as well as the desired flow values are bounded. Our algorithm for this case generalizes the algorithm (by Perl and Shiloach [14] for k=2 and Fortune, Hopcroft and Wyllie [11] for k≥3) for the k-linkage problem in acyclic digraphs. Besides, the problem is polynomial in general digraphs if all capacities are 1 and the two flows have the same balance for all vertices in N, but remains NP-complete if the network contains at least one arc with capacity 2 (and the others have capacity 1). Finally, we also show that the following properties are NP-complete to decide on digraphs: the existence of a spanning connected Eulerian subdigraph, the existence of a cycle factor in which all cycles have even length and finally the existence of a cycle factor in which all cycles have odd length. © 2014 Elsevier B.V.

Schwartz J.C.,University of Minnesota | Lefranc M.-P.,Montpellier University | Murtaugh M.P.,University of Minnesota
Immunogenetics | Year: 2012

We have characterized the organization, complexity, and expression of the porcine (Sus scrofa domestica) immunoglobulin lambda (IGL) light chain locus, which accounts for about half of antibody light chain usage in swine, yet is nearly totally unknown. Twenty-two IGL variable (IGLV) genes were identified that belong to seven subgroups. Nine genes appear to be functional. Eight possess stop codons, frameshifts, or both, and one is missing the V-EXON. Two additional genes are missing an essential cysteine residue and are classified as ORF (open reading frame). The IGLV genes are organized in two distinct clusters, a constant (C)-proximal cluster dominated by genes similar to the human IGLV3 subgroup, and a C-distal cluster dominated by genes most similar to the human IGLV8 and IGLV5 subgroups. Phylogenetic analysis reveals that the porcine IGLV8 subgroup genes have recently expanded, suggesting a particularly effective role in immunity to porcinespecific pathogens. Moreover, expression of IGLV genes is nearly exclusively restricted to the IGLV3 and IGLV8 genes. The constant locus comprises three tandem cassettes comprised of a joining (IGLJ) gene and a constant (IGLC) gene, whereas a fourth downstream IGLJ gene has no corresponding associated IGLC gene. Comparison of individual BACs generated from the same individual revealed polymorphisms in IGLC2 and several IGLV genes, indicating that allelic variation in IGLV further expands the porcine antibody light chain repertoire. © Springer-Verlag 2011.

Accumulating evidence suggests that changes of the protein synthesis machinery alter translation of specific mRNAs and participate in malignant transformation. Here we show that protein kinase C α (PKCα) interacts with TRM61, the catalytic subunit of the TRM6/61 tRNA methyltransferase. The TRM6/61 complex is known to methylate the adenosine 58 of the initiator methionine tRNA (tRNAiMet), a nuclear post-transcriptional modification associated with the stabilization of this crucial component of the translation-initiation process. Depletion of TRM6/61 reduced proliferation and increased death of C6 glioma cells, effects that can be partially rescued by overexpression of tRNAiMet. In contrast, elevated TRM6/61 expression regulated the translation of a subset of mRNAs encoding proteins involved in the tumorigenic process and increased the ability of C6 cells to form colonies in soft agar or spheres when grown in suspension. In TRM6/61/tRNAiMet-overexpressing cells, PKCα overexpression decreased tRNAiMet expression and both colony- and sphere-forming potentials. A concomitant increase in TRM6/TRM61 mRNA and tRNAiMet expression with decreased expression of PKCα mRNA was detected in highly aggressive glioblastoma multiforme as compared with Grade II/III glioblastomas, highlighting the clinical relevance of our findings. Altogether, we suggest that PKCα tightly controls TRM6/61 activity to prevent translation deregulation that would favor neoplastic development.Oncogene advance online publication, 3 August 2015; doi:10.1038/onc.2015.244. © 2015 Macmillan Publishers Limited

Haddad T.,Jijel University | Thibault L.,Montpellier University
Mathematical Programming | Year: 2010

In this paper we prove a theorem on the existence of a global solution of a differential inclusion governed by a class of nonconvex sweeping processes with unbounded pertubations. The perturbations are not required to be convex valued. © 2009 Springer and Mathematical Programming Society.

Cystic fibrosis (CF) is one of the most common indications for preimplantation genetic diagnosis (PGD) for single gene disorders, giving couples the opportunity to conceive unaffected children without having to consider termination of pregnancy. However, there are no available standardized protocols, so that each center has to develop its own diagnostic strategies and procedures. Furthermore, reproductive decisions are complicated by the diversity of disease-causing variants in the CFTR (cystic fibrosis transmembrane conductance regulator) gene and the complexity of correlations between genotypes and associated phenotypes, so that attitudes and practices toward the risks for future offspring can vary greatly between countries. On behalf of the EuroGentest Network, eighteen experts in PGD and/or molecular diagnosis of CF from seven countries attended a workshop held in Montpellier, France, on 14 December 2011. Building on the best practice guidelines for amplification-based PGD established by ESHRE (European Society of Human Reproduction and Embryology), the goal of this meeting was to formulate specific guidelines for CF-PGD in order to contribute to a better harmonization of practices across Europe. Different topics were covered including variant nomenclature, inclusion criteria, genetic counseling, PGD strategy and reporting of results. The recommendations are summarized here, and updated information on the clinical significance of CFTR variants and associated phenotypes is presented.European Journal of Human Genetics advance online publication, 27 May 2015; doi:10.1038/ejhg.2015.99. © 2015 Macmillan Publishers Limited

OBJECTIVE:: Autophagy, an important antiviral process triggered during HIV-1 entry by gp41-dependent membrane fusion, is repressed in infected CD4 T cells by an unknown mechanism. The aim of this study was to identify the role of viral infectivity factor (Vif) in the autophagy blockade.DESIGN/METHODS:: To determine the role of Vif in autophagy inhibition, we used cell lines that express CD4 and CXCR4 and primary CD4 T cells. Pull-down experiments, immunoprecipitation assays and computational analyses were performed to analyze the interaction between Vif and light chain 3B (LC3B), a major autophagy component, in presence or absence of the antiviral host factor apolipoprotein B mRNA-editing enzyme-catalytic polypeptide-like 3G (APOBEC3G), after HIV-1 infection or ectopic expression of Vif. Autophagy was analyzed after infection by viruses expressing Vif (NL4.3) or not (NL4.3ΔVif), or after exogenous Vif expression.RESULTS:: We demonstrate that the C-terminal part of Vif interacts directly with LC3B, independently of the presence of APOBEC3G.Vif binds to pro-LC3 and autophagy-related protein 4 cleaved LC3 forms, and glycine 120, the amino acid conjugated to phosphatidylethanolamine on autophagosomes, is required. Importantly, we evidence that Vif inhibits autophagy during HIV-1 infection. Indeed, autophagy is detected in target cells infected by NL4.3ΔVif, but prevented in cells infected by NL4.3. Furthermore, autophagy triggered in NL4.3ΔVif-infected cells is inhibited when Vif is expressed in trans but is still active when target cells express a mutant of Vif that binds weakly to LC3B.CONCLUSION:: Our study unveils that Vif inhibits autophagy independently of its action on APOBEC3G and, therefore, suggest a new function of this viral protein in restricting innate antiviral mechanisms. © 2014 Lippincott Williams & Wilkins, Inc.

Becker D.,Section dArcheologie et Paleontologie | Antoine P.-O.,Montpellier University | Maridet O.,CAS Institute of Vertebrate Paleontology and Paleoanthropology
Journal of Systematic Palaeontology | Year: 2013

A newly discovered, well-preserved skull and associated fragment of a juvenile mandible from the Early Oligocene locality of Poillat (Canton Jura, NW Switzerland), bearing close affinities with the rhinocerotid Protaceratherium albigense (Roman, 1912), are attributed to a new small-sized representative of early diverging Rhinocerotinae, Molassitherium delemontense gen. et sp. nov. Other specimens from Western Europe, formerly questionably referred to Epiaceratherium Abel, 1910, are assigned to this new genus. Comparison with the previously described Protaceratherium Abel, 1910 (including type material) and a phylogenetic analysis highlight the mismatch of Protaceratherium minutum (Cuvier, 1822) and Protaceratherium albigense (Roman, 1912). Given the topology of the most parsimonious tree, a basal split within Rhinocerotidae coincides with the well-supported divergence of the Elasmotheriinae and Rhinocerotinae clades. Relationships within Rhinocerotinae are [Epiaceratherium bolcense Abel, 1910 [Epiaceratherium magnum Uhlig, 1999 [Molassitherium gen. nov. [Mesaceratherium Heissig, 1969 [Pleuroceros Roger, 1898 [Protaceratherium minutum (Cuvier, 1822) [Plesiaceratherium mirallesi (Crusafont, Villalta and Truyols, 1955) [Aceratheriini, Rhinocerotini]]]]]]]]. The only paraphyletic genus in the analysis is Epiaceratherium, with the earliest Oligocene Epiaceratherium bolcense Abel, 1910 being sister taxon to an [Epiaceratherium magnum Uhlig, 1999, Rhinocerotinae] clade. In the single most parsimonious tree, Molassitherium gen. nov., included within the early diverging Rhinocerotinae, forms a clade encompassing Molassitherium delemontense gen. et sp. nov. and the type species Molassitherium albigense comb. nov. The range of Molassitherium delemontense gen. et sp. nov. is so far restricted to the late Early-early Late Oligocene interval in Western Europe (Germany, Switzerland, France; late MP22-MP25). © 2013 Copyright Taylor and Francis Group, LLC.

Canavese F.,Montpellier University
Journal of Pediatric Orthopaedics | Year: 2015

BACKGROUND:: Rod migration into the spinal canal after posterior instrumented fusion is a rare complication causing late-onset neurological symptoms. The purpose of the present study is to report a case of a 13-year-old boy with spastic cerebral palsy and related neuromuscular kyphoscoliosis who developed late-onset neurological deterioration secondary to progressive implant migration into the spinal canal over a 5-year period. METHODS:: A decision was made to remove both rods to achieve decompression. Intraoperative findings were consistent with information gained from preoperative imaging. The rods were found to have an intracanal trajectory at T9-T10 for the right rod and T12-L2 for the left rod. RESULTS:: The cause of implant migration, with progressive laminar erosion slow enough to generate a solid mass behind, was progressive kyphosis in a skeletally immature patient with neuromuscular compromise. CONCLUSIONS:: Fixation type, early surgery, and spasticity management contributed significantly to the presenting condition. Mechanical factors and timing of surgery played a decisive role in this particular presentation. LEVEL OF EVIDENCE:: Case report and review of the literature. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.

Campbell I.A.,Montpellier University | Petit D.C.M.C.,Imperial College London
Journal of the Physical Society of Japan | Year: 2010

An overview is given of experimental data on Heisenberg spin glass materials so as to make detailed comparisons with numerical results on model Heisenberg spin glasses, with particular reference to the chiral driven ordering transition scenario due to Kawamura and collaborators. On weak anisotropy systems, experiments show critical exponents which are very similar to those estimated numerically for the model Heisenberg chiral ordering transition but which are quite different from those at Ising spin glass transitions. Again on weak anisotropy Heisenberg spin glasses, experimental torque data show well defined in-field transverse ordering transitions up to strong applied fields, in contrast to Ising spin glasses where fields destroy ordering. When samples with stronger anisotropies are studied, critical and in-field behavior tend progressively towards the Ising limit. It can be concluded that the essential physics of laboratory Heisenberg spin glasses mirrors that of model Heisenberg spin glasses, where chiral ordering has been demonstrated numerically. © 2010 The Physical Society of Japan.

Klein M.,VU University Amsterdam | Duffau H.,Montpellier University | De Witt Hamer P.C.,VU University Amsterdam
Journal of Neuro-Oncology | Year: 2012

Compared to classical oncological outcome measures such as time to progression and survival, the importance of cognitive functioning in patients with diffuse infiltrative brain tumors has only recently been recognized. Apart from the relatively low incidence and the invariably fatal outcome of gliomas, the general assumption that cognitive assessment is time-consuming and burdensome contributes to this notion. Our understanding of the effects of brain surgery on cognition, for instance, is largely based on studies in surgical patients with refractory epilepsy, with only a limited number of studies in surgical patients with gliomas. The impact of other factors affecting cognition in glioma patients such as direct tumor effects, radiotherapy and chemotherapy, and medical treatment, including antiepileptic drugs and steroids, have been studied more extensively. The purpose of this paper is to provide an overview of cognition in patients with diffuse infiltrative gliomas and the impact of resective surgery as well as other tumor and treatment-related factors. © Springer Science+Business Media, LLC. 2012.

Sibille N.,Montpellier University
Biochemical Society transactions | Year: 2012

In recent years, IDPs (intrinsically disordered proteins) have emerged as pivotal actors in biology. Despite IDPs being present in all kingdoms of life, they are more abundant in eukaryotes where they are involved in the vast majority of regulation and signalling processes. The realization that, in some cases, functional states of proteins were partly or fully disordered was in contradiction to the traditional view where a well defined three-dimensional structure was required for activity. Several experimental evidences indicate, however, that structural features in IDPs such as transient secondary-structural elements and overall dimensions are crucial to their function. NMR has been the main tool to study IDP structure by probing conformational preferences at residue level. Additionally, SAXS (small-angle X-ray scattering) has the capacity to report on the three-dimensional space sampled by disordered states and therefore complements the local information provided by NMR. The present review describes how the synergy between NMR and SAXS can be exploited to obtain more detailed structural and dynamic models of IDPs in solution. These combined strategies, embedded into computational approaches, promise the elucidation of the structure-function properties of this important, but elusive, family of biomolecules.

Canavese F.,Estaing University Hospital Center | Dimeglio A.,Montpellier University
World Journal of Orthopaedics | Year: 2013

Development of the spine and thoracic cage consists of a complex series of events involving multiple metabolic processes, genes and signaling pathways. During growth, complex phenomena occur in rapid succession. This succession of events, this establishment of elements, is programmed according to a hierarchy. These events are well synchronized to maintain harmonious limb, spine and thoracic cage relationships, as growth in the various body segments does not occur simultaneously at the same magnitude or rate. In most severe cases of untreated progressive earlyonset spinal deformities, respiratory insufficiency and pulmonary and cardiac hypertension (cor pulmonale ), which characterize thoracic insufficiency syndrome (TIS), can develop, sometimes leading to death. TIS is the inability of the thorax to ensure normal breathing. This clinical condition can be linked to costo-vertebral malformations (e.g. , fused ribs, hemivertebrae, congenital bars), neuromuscular diseases (e.g. , expiratory congenital hypotonia), Jeune or Jarcho-Levin syndromes or to 50% to 75% fusion of the thoracic spine before seven years of age. Complex spinal deformities alter normal growth plate development, and vertebral bodies become progressively distorted, perpetuating the disorder. Therefore, many scoliotic deformities can become growth plate disorders over time. This review aims to provide a comprehensive review of how spinal deformities can affect normal spine and thoracic cage growth. Previous conceptualizations are integrated with more recent scientific data to provide a better understanding of both normal and abnormal spine and thoracic cage growth. © 2013 Baishideng.

Konczak I.,CSIRO | Roulle P.,Montpellier University
Food Research International | Year: 2011

A high level of antioxidant activity of lipophilic fractions obtained from commercially grown native Australian fruits, as evaluated in the oxygen radical absorbance capacity assay for lipophilic antioxidants (ORAC-L), was identified for the first time. The level of contribution of lipophilic fractions varied from 5.8% (quandong) to 30.7% (riberry) of the total oxygen radical scavenging capacity (ORAC-T). Vitamin E components - α-tocopherol, γ-tocopherol and δ-tocopherol and lutein - were identified as the main sources of this activity. Among the evaluated sources, Kakadu plum emerges as a fruit with unique nutritional qualities: it exhibited a superior ORAC-T value (430.0 μM trolox eq/g fresh weight, TEq/g FW) with 26.7% contribution of the lipophilic fraction. The major compounds of Kakadu plum's lipophilic fraction were α-tocopherol (1.022 ± 0.1. mg/100. g, FW), lutein (0.26 ± 0.01. mg/100. g FW) and chlorophyll a and b (2.72 ± 0.1 and 0.54 ± 0.1. mg/100. g FW, respectively). With regards to mineral content, the levels of major minerals, such as potassium, phosphorus, calcium, magnesium, and trace elements such as iron, zinc, manganese, selenium and copper as well as cobalt, nickel, aluminium and led in native Australian fruits are similar to the levels of these elements in a range of vegetables and frutis produced and consumed elsewhere. © 2011 Elsevier Ltd.

Gueydan F.,Montpellier University | Precigout J.,CNRS Earth Sciences Institute of Orleans
Tectonophysics | Year: 2014

Analogue and numerical models have shown that the strength of the lithospheric mantle controls the mode of lithosphere deformation. In extension, the presence or absence of a high strength brittle mantle respectively leads to localized or distributed rifting. However, first order geophysical data question the existence of such a brittle mantle. Here we use 2-D finite-element large strain modelling to quantify the impact of a ductile localizing mantle - instead of brittle - in triggering continental rifting. As a novelty, the mantle rheology considers the effect of grain boundary sliding during strain-induced grain size reduction, which may promote a significant strength drop and subsequent strain localization at low mantle temperature (<. 700-800. °C). Our results reveal that such ductile localizing mantle implies varying modes of continental rifting that mainly depend on both the amount of weakening in the ductile mantle and the strength of the lower ductile crust. A medium to strong lower crust implies coupling between the upper crust and ductile localizing mantle, yielding to narrow continental rifting. In contrast, a weak lower crust implies decoupling between the upper crust and ductile localizing mantle, giving rise to a switch from distributed faulting at incipient strain to localized faulting at large strain. Ductile strain localization in the lithospheric mantle is therefore sufficient to trigger continental rifting, although a critical amount of weakening is required. Such ductile localizing mantle provides a relevant geological and mechanical alternative to the brittle mantle. It moreover provides a wider variety of modes of upper crustal faulting that are commonly observed in nature. © 2013 Elsevier B.V.

Richard O.,Montpellier University
Memorie della Societa Astronomica Italiana, Supplementi - Journal of the Italian Astronomical Society, Supplement | Year: 2012

Due to nuclear reactions within their interior, stars are the generators of the chemical evolution of galaxies. In this context, it is important to recognize that the chemical abundances observed in stellar surfaces are most often not the original ones. In fact, due to atomic diffusion, the atomic species in stars move either downwards or upwards. For solar metallicity stars, it is well accepted within the international community that stellar modeling should include atomic diffusion. However it is not yet considered as a standard process in lower metallicity stars. In this paper I will present the effect of atomic diffusion on surface abundances and on abundance profile in metal poor stars. The effect of the initial metallicity will also be addressed. © SAIt 2012.

Avadi A.,Montpellier University | Freon P.,IRD Montpellier
Fisheries Research | Year: 2013

This review aims to synthesise and discuss current literature applying the Life Cycle Assessment (LCA) framework for the environmental assessment of fisheries. The review introduces and illustrates the LCA framework, and highlights energy use by fishing vessels, among other key factors determining environmental impacts of fisheries operations. Moreover, the review concludes with recommendations on future developments of LCA in the fisheries and seafood sectors.We reviewed 16 studies on LCA applied to fisheries, with perspectives from a few additional publications on closely related topics. The main Aspects considered in the ad hoc comparison of studies include: scope and system boundaries, functional units, allocation strategies for co-products, conventional and fishery-specific impact categories used, fuel use, impact assessment methods, level of detail in inventories, normalisation of results and sensitivity analyses.A number of patterns and singularities were detected. Fishery-specific impact categories, despite not being standardised, and fuel use in fishing operations were identified as the main contributors to environmental impacts. Energy efficiency was found to be strongly related to the fishing gear used. Several studies discussed the impacts of antifouling substances and metals use. The need for standardisation of fisheries LCA research is justified and ideas on how to do so and what elements to standardise (fisheries-specific impact categories, inventory details, normalisation references, etc.) are discussed. Finally, fisheries LCA constitute a useful research field when studying the sustainability of seafood and fisheries-based agrifood, and it should likewise contribute to an ecosystem approach to fisheries. © 2013 Elsevier B.V.

Spinelli N.,CNRS Molecular Chemistry Department | Defrancq E.,CNRS Molecular Chemistry Department | Morvan F.,Montpellier University
Chemical Society Reviews | Year: 2013

Conjugation of oligonucleotides (ONs) to a variety of reporter groups has been the subject of intensive research during the last decade. Conjugation is indeed of great interest because it can be used not only to improve the existing ONs properties but also to impart new ones. In this context tremendous efforts have been made to conjugate carbohydrate moieties to ONs. Indeed carbohydrates play an important role in biological processes such as signal transduction and cell adhesion through the recognition with sugar-binding proteins (i.e. lectins) located on the surface of cells. For this reason, carbohydrate-oligonucleotide conjugates (COCs) have been first developed for improving the poor cellular uptake or tissue specific delivery of ONs through receptor-mediated endocytosis. Besides the targeted ONs delivery, carbohydrate-oligonucleotide conjugates (COCs) are also evaluated in the context of carbohydrate biochips in which surface coating with carbohydrates is achieved by using the DNA-directed immobilization strategy (DDI). Peptide nucleic acids (PNAs) have also been extensively investigated as a surrogate of DNA for diverse applications. Therefore attachment of carbohydrate moieties to this class of molecules has been studied. The aforementioned applications of COCs require mimicking of the natural processes, in which the weak individual protein-carbohydrate binding is overcome by using multivalent interactions. This tutorial review focuses on the recent advances in carbohydrate-oligonucleotide conjugates and describes the major synthetic approaches available. In addition, an overview of applications that have been developed using various scaffolds allowing multivalent interactions is provided. Finally recent results on the use of peptide nucleic acids as oligonucleotides surrogate are described. © 2013 The Royal Society of Chemistry.

Abundant remains of Protechimys major Schlosser (1884) (Rodentia, Theridomyinae) from Mas-de-Pauffié (Lot, France; standard-locality MP26, e.g., BiochroM'1997; Early Chattian) are described and their morphological and dimensional variability are analyzed. At this locality, and also at Les-Milles (Bouches-du-Rhône), P. major is associated with a few teeth of Archaeomys-Blainvillimys sp. Due to this scarcity and to similar evolutionary trends in the pattern of lower molars, it is not possible to find accurate features likely to distinguish Protechimys from Archaeomys or advanced Blainvillimys, but lines of research are given. Their co-occurrence with Issiodoromys pauffiensis Vianey-Liaud (1976) is documented at localities with different depositional conditions; together with the analysis of precise and focused samples made in the limited outcrop, it contributes to demonstrate the temporal homogeneity of the MP26 rodent assemblage from Mas-de-Pauffié. © 2015 Académie des sciences.

Duran A.,Montpellier University
International Journal for Numerical Methods in Fluids | Year: 2015

In the following lines, we propose a numerical scheme for the shallow-water system supplemented by topography and friction source terms, in a 2D unstructured context. This work proposes an improved version of the well-balanced and robust numerical model recently introduced by Duran et al. (J. Comp. Phys., 235, 565-586, 2013) for the pre-balanced shallow-water equations, accounting for varying topography. The present work aims at relaxing the robustness condition and includes a friction term. To this purpose, the scheme is modified using a recent method, entirely based on a modified Riemann solver. This approach preserves the robustness and well-balanced properties of the original scheme and prevents unstable computations in the presence of low water depths. A series of numerical experiments are devoted to highlighting the performances of the resulting scheme. Simulations involving dry areas, complex geometry and topography are proposed to validate the stability of the numerical model in the neighbourhood of wet/dry transitions. © 2015 John Wiley & Sons, Ltd.

Winter C.,University of Vienna | Bouvier T.,Montpellier University | Weinbauer M.G.,University Pierre and Marie Curie | Thingstad T.F.,University of Bergen
Microbiology and Molecular Biology Reviews | Year: 2010

A trade-off between strategies maximizing growth and minimizing losses appears to be a fundamental property of evolving biological entities existing in environments with limited resources. In the special case of unicellular planktonic organisms, the theoretical framework describing the trade-offs between competition and defense specialists is known as the "killing the winner" hypothesis (KtW). KtW describes how the availability of resources and the actions of predators (e.g., heterotrophic flagellates) and parasites (e.g., viruses) determine the composition and biogeochemical impact of such organisms. We extend KtW conceptually by introducing size- or shape-selective grazing of protozoans on prokaryotes into an idealized food web composed of prokaryotes, lytic viruses infecting prokaryotes, and protozoans. This results in a hierarchy analogous to a Russian doll, where KtW principles are at work on a lower level due to selective viral infection and on an upper level due to size- or shape-selective grazing by protozoans. Additionally, we critically discuss predictions and limitations of KtW in light of the recent literature, with particular focus on typically neglected aspects of KtW. Many aspects of KtW have been corroborated by in situ and experimental studies of isolates and natural communities. However, a thorough test of KtW is still hampered by current methodological limitations. In particular, the quantification of nutrient uptake rates of the competing prokaryotic populations and virus population-specific adsorption and decay rates appears to be the most daunting challenge for the years to come. Copyright © 2010, American Society for Microbiology. All Rights Reserved.

Hanghoj K.,Lamont Doherty Earth Observatory | Kelemen P.B.,Lamont Doherty Earth Observatory | Hassler D.,Statoil | Godard M.,Montpellier University
Journal of Petrology | Year: 2010

The Oman ophiolite consists of several massifs cropping out along a 500 km long band trending NW-SE along the coast of Oman; it is one of the best exposed sections of oceanic crust and mantle in the world. There is a gradient in igneous processes and composition in the ophiolite, with the northern massifs recording a polygenetic igneous history involving an increasingly important subduction component, whereas the southern massifs were formed primarily via a mid-ocean ridge basalt (MORB)-like, single-stage process at a submarine spreading ridge. In this study we use geochemical data from Wadi Tayin, which is one of the southern massifs of the Oman ophiolite, to constrain the composition and genesis of oceanic crust and upper mantle. The Wadi Tayin harzburgites are residues of partial melting that are as depleted as the most depleted mid-ocean ridge peridotites. They have low middle- to heavy rare earth element ratios, most probably reflecting melting close to and beyond the exhaustion of clinopyroxene. Like many abyssal peridotites, the Wadi Tayin samples show enrichment in highly incompatible elements, giving rise to U-shaped MORB-normalized trace element patterns. We favor the idea that this is caused by enrichment of highly incompatible elements along grain boundaries in peridotite, which may be the result of near-equilibrium partitioning between grain boundaries and grain interiors, rather than disequilibrium processes. Equilibrium partitioning between crystals and grain boundaries during melting and melt extraction is also our preferred explanation for ubiquitous high Pb contents relative to Ce and La in our samples as well as in most abyssal peridotites. The Wadi Tayin samples record substantial variability in terms of osmium isotopic composition and platinum group element (PGE) concentrations. The more radiogenic nature of the dunites and impregnated peridotites compared with the residual harzburgites may be due to relatively high . 187Os/. 188Os in melt transported through the dunites. The presence of residual peridotites with whole-rock osmium isotopic compositions less radiogenic than MORB may be explained by melting of a veined (upwelling) mantle forming mixed melts in which much of the Os derives from veins with high Re/Os in a matrix of previously depleted peridotite. An important result of this study is that the shallowest samples are refertilized (i.e. anomalously enriched in incompatible elements), and record relatively high metamorphic closure temperatures. These observations suggest that migrating melt underwent crystallization during rapid cooling in the uppermost mantle during and immediately after ridge magmatism. A variety of geothermometers all yield the result that the stratigraphically highest harzburgites equilibrated at higher temperature than the deeper ones. The systematic decrease in closure temperature with increasing depth below the Moho transition zone probably reflects systematic variation in cooling rate as a function of depth in the mantle section. We hypothesize that the refertilization and higher closure temperatures recorded by the uppermost mantle samples are linked. More rapid cooling led to higher closure temperatures, and to partial crystallization of migrating melts in the shallowest part of the mantle section, yielding slightly elevated abundances of elements such as Ca and Na, and incompatible trace elements. © The Author 2010. Published by Oxford University Press.

Oliva M.,CNRS Laboratory of Plant Reproduction and Development | Farcot E.,Montpellier University | Vernoux T.,CNRS Laboratory of Plant Reproduction and Development
Current Opinion in Plant Biology | Year: 2013

Recent years have seen an impressive increase in our knowledge of the topology of plant hormone signaling networks. The complexity of these topologies has motivated the development of models for several hormones to aid understanding of how signaling networks process hormonal inputs. Such work has generated essential insights into the mechanisms of hormone perception and of regulation of cellular responses such as transcription in response to hormones. In addition, modeling approaches have contributed significantly to exploring how spatio-temporal regulation of hormone signaling contributes to plant growth and patterning. New tools have also been developed to obtain quantitative information on hormone distribution during development and to test model predictions, opening the way for quantitative understanding of the developmental roles of hormones. © 2012 Elsevier Ltd.

Gioan E.,Montpellier University
Medical image computing and computer-assisted intervention : MICCAI ... International Conference on Medical Image Computing and Computer-Assisted Intervention | Year: 2012

We present a new method to analyze, classify and characterize 3D landmark-based shapes. It is based on a framework provided by oriented matroid theory, that is on a combinatorial encoding of convexity properties. We apply this method to a set of skull shapes presenting various types of coronal craniosynostosis.

Brodolin K.,Montpellier University
Transcription | Year: 2011

Promoter DNA melting, culminating in the loading of the single-stranded DNA template into the RNA polymerase active site, is a key step in transcription initiation. Recently, the first transcription inhibitors found to block distinct steps of promoter melting were characterized. Here, the impact of these studies is discussed with respect to the current models of transcription initiation.

Renard E.,Montpellier University
Diabetes Technology and Therapeutics | Year: 2010

Although European groups have initiated innovative clinical research in the field of insulin pump therapy, insulin pump use remains currently limited in many European countries, and well behind that in the United States. The main reason is the late approval of cost coverage by most national healthcare insurance systems, which is still lacking in some countries. Partly in connection with this delay, the number of trained physicians to pump therapy is low in many countries, while diabetes educators do not exist as an acknowledged entity in many European countries, and pump manufacturers are excluded from the education process of patients in most of them. Pump use in pediatric-age populations has strongly increased during the last years, following the evidence-based demonstrations of the benefits of pump therapy in these patients leading to an international consensus on pump indications and practice. Failure to control type 1 diabetes to target and frequent hypoglycemia under multiple daily insulin injections are consensuSbased but restrictive indications for pump therapy in adults in most countries. The economic burden on healthcare insurance systems does not facilitate wider use of insulin pumps, but a significant expansion of pump therapy according to consensuSbased indications is still expected thanks to the growing knowledge of physicians in technologies and because of the increasing interest of patients to use technology to improve their control of diabetes and health-related quality of life. More sophisticated technologies connected to pump therapy, such as continuous glucose monitoring or telemedicine, will need specific cost coverage for a true implementation in diabetes care in Europe. © 2010, Mary Ann Liebert, Inc.