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Marseille, France

Aix-Marseille University is a public research university located in Provence, southern France. With roots dating back to 1409, the university was formed by the merger of the University of Provence, the University of the Mediterranean and Paul Cézanne University. The merger became effective on 1 January 2012, resulting in the creation of the largest university in France and the French-speaking world, with about 70,000 students. AMU has the largest financial endowment of any academic institution in the Francophone world, standing at €650 million.The university is organized around five main campuses situated in Aix-en-Provence and Marseille. Apart from its major campuses, AMU owns and operates facilities in Arles, Aubagne, Avignon, Digne-les-Bains, Gap, La Ciotat, Lambesc and Salon-de-Provence. The university is headquartered at the Pharo, Marseille.AMU has produced many notable alumni in the fields of law, politics, business, economics and literature. To date, there have been four Nobel Laureates amongst its alumni and faculty, as well as a two-time recipient of the Pulitzer Prize, three César Award winners, several heads of state, parliamentary speakers, government ministers, ambassadors and members of the Institut de France.AMU has hundreds of research and teaching partnerships, including close collaboration with the French National Centre for Scientific Research and the French Atomic Energy and Alternative Energies Commission . AMU is a member of numerous academic organisations including the European University Association and the Mediterranean Universities Union . Wikipedia.

Mekri F.,Saida University | Elghali S.B.,Aix - Marseille University | Benbouzid M.E.H.,CNRS Brest Laboratory of Mechanics and Systems Laboratory
IEEE Transactions on Sustainable Energy | Year: 2013

This paper deals with the use of permanent magnet multiphase generators in marine current turbines with the aim to highlight their fault-tolerance. In this context, the performances and the fault-tolerant capabilities of a five-phase permanent magnet synchronous generator are evaluated within a marine current turbine and compared to a classical three-phase generator. For both topologies, a robust nonlinear control strategy is adopted. The adopted control consists of an adaptive control approach that combines three strategies: a maximum power point tracking (MPPT), an optimal fault-adaptive reference current generation, and high-order sliding modes. Simulations are carried-out using a Matlab/Simulink-based marine current turbine simulator to analyze the generator performances during open-circuit faults. Conclusions are then derived regarding multiphase generators' key features for marine applications. © 2010-2012 IEEE.

Kara A.,University of Central Florida | Kara A.,Cergy-Pontoise University | Enriquez H.,CNRS Orsay Institute for Molecular Science | Seitsonen A.P.,Physikalisch Chemisches Institute der University Zrich | And 5 more authors.
Surface Science Reports | Year: 2012

Silicenethe silicon-based counterpart of graphenehas a two dimensional structure that is responsible for the variety of potentially useful chemical and physical properties. The existence of silicene has been achieved recently owing to experiments involving epitaxial growth of silicon as stripes on Ag(001), ribbons on Ag(110), and sheets on Ag(111). The nano-ribbons observed on Ag(110) were foundby both high definition experimental scanning tunneling microscopy images and density functional theory calculationsto consist of an arched honeycomb structure. Angle resolved photo-emission experiments on these silicene nano-ribbons on Ag(110), along the direction of the ribbons, showed a band structure which is analogous to the Dirac cones of graphene. Unlike silicon surfaces, which are highly reactive to oxygen, the silicene nano-ribbons were found to be resistant to oxygen reactivity. On the theoretical side, recent extensive efforts have been deployed to understand the properties of standalone silicene sheets and nano-ribbons using both tight-binding and density functional theory calculations. Unlike graphene it is demonstrated that silicene sheets are stable only if a small buckling (0.44 ) is present. The electronic properties of silicene nano-ribbons and silicene sheets were found to resemble those of graphene. Although this is a fairly new avenue, the already obtained outcome from these important first steps in understanding silicene showed promising features that could give a new future to silicon in the electronics industry, thus opening a promising route toward wide-range applications. In this review, we plan to introduce silicene by presenting the available experimental and theoretical studies performed to date, and suggest future directions to be explored to make the synthesis of silicene a viable one. © 2011 Elsevier B.V. All rights reserved.

Kelly R.G.,Aix - Marseille University
Current Topics in Developmental Biology | Year: 2012

Ten years ago, a population of cardiac progenitor cells was identified in pharyngeal mesoderm that gives rise to a major part of the amniote heart. These multipotent progenitor cells, termed the second heart field (SHF), contribute progressively to the poles of the elongating heart tube during looping morphogenesis, giving rise to myocardium, smooth muscle, and endothelial cells. Research into the mechanisms of SHF development has contributed significantly to our understanding of the properties of cardiac progenitor cells and the origins of congenital heart defects. Here recent data concerning the regulation, clinically relevant subpopulations, evolution and lineage relationships of the SHF are reviewed. Proliferation and differentiation of SHF cells are controlled by multiple intercellular signaling pathways and a transcriptional regulatory network that is beginning to be elucidated. Perturbation of SHF development results in common forms of congenital heart defects and particular progenitor cell subpopulations are highly relevant clinically, including cells giving rise to myocardium at the base of the pulmonary trunk and the interatrial septum. A SHF has recently been identified in amphibian, fish, and agnathan embryos, highlighting the important contribution of these cells to the evolution of the vertebrate heart. Finally, SHF-derived parts of the heart share a lineage relationship with craniofacial skeletal muscles revealing that these progenitor cells belong to a broad cardiocraniofacial field of pharyngeal mesoderm. Investigation of the mechanisms underlying the dynamic process of SHF deployment is likely to yield further insights into cardiac development and pathology. © 2012 Elsevier Inc.

Pandelia M.-E.,Max Planck Institute for Chemistry | Lubitz W.,Max Planck Institute for Chemistry | Nitschke W.,Aix - Marseille University
Biochimica et Biophysica Acta - Bioenergetics | Year: 2012

Group 1 hydrogenases are periplasmic enzymes and are thus strongly affected by the outside world the cell experiences. This exposure has brought about an extensive heterogeneity in their cofactors and redox partners. Whereas in their majority they are very O2-sensitive, several enzymes of this group have been recently reported to be O2-tolerant. Structural and biochemical studies have shown that this O2-tolerance is conferred by the presence of an unusual iron-sulfur cofactor with supernumerary cysteine ligation (6 instead of 4 Cys, hence called '6C cluster'). This atypical cluster coordination affords redox plasticity (i.e. two-redox transitions), unprecedented for this type of cofactors and likely involved in resistance to O2. Genomic screening and phylogenetic tree reconstruction revealed that 6C hydrogenases form a monophyletic clade and are unexpectedly widespread among bacteria. However, several other well-defined clades are observed, which indicate early diversification of the enzyme into different subfamilies. The various idiosyncrasies thereof are shown to comply with a very simple rule: phylogenetic grouping of hydrogenases directly correlates with their specific functions and hence biochemical characteristics. The observed variability results from gene duplication, gene shuffling and subsequent adaptation of the diversified enzymes to specific environments. An important factor for this diversification seems to have been the emergence of molecular oxygen. Hydrogenases appear to have dealt with oxidative stress in various ways, the most successful of which, however, was the innovation of the 6C-cluster conferring pronounced O2-tolerance to the parent enzymes. © 2012 Elsevier Ltd. All rights reserved.

Flustra bouchardii Audouin, 1826, erected without description for a Mediterranean bryozoan species illustrated by Savigny (1817), remained enigmatic. It is shown here that this forgotten species belongs in Monoporella species (Cheilostomata, Monoporellidae), is common in the Eastern Mediterranean and was erroneously considered to be an Indo-Pacific species. Monoporella bouchardii is endemic to the Central and Eastern Mediterranean and might be a relict of the warm water pre-Messinian fauna. Its endemism is attested by the lack of records of any Monoporella species from the nearby Atlantic and the Red Sea, except for specimens recently discovered in the southern part of the Gulf of Suez. The similarity between these specimens and M. bouchardii suggests that they represent a sibling species or a case of anti-Lessepsian migration.

Lopez C.,Aix - Marseille University | Blanke O.,Ecole Polytechnique Federale de Lausanne
Current biology : CB | Year: 2014

The hundredth anniversary of Robert Bárány's Nobel Prize in Medicine offers the opportunity to highlight the importance of his discoveries on the physiology and pathophysiology of the vestibular organs. Bárány developed the method of caloric vestibular stimulation that revolutionized the investigation of the semicircular canals and that is still widely used today. Caloric vestibular stimulation launched experimental vestibular research that was relevant to comprehend the evolution of human locomotion, and Bárány's tests continue to be used in neuroscience to understand the influence of vestibular signals on bodily perceptions, cognition and emotions. Only during the last 20 years has caloric vestibular stimulation been merged with brain imaging to localize the human vestibular cortex. Copyright © 2014 Elsevier Ltd. All rights reserved.

Chevallier J.,France Business School | Sevi B.,Aix - Marseille University
Environmental and Resource Economics | Year: 2014

Pricing carbon is a central concern in environmental economics, due to the worldwide importance of emissions trading schemes to regulate pollution. This paper documents the presence of small and large jumps in the stochastic process of the CO2 futures price. The large jumps have a discrete origin, i.e. they can arise from various demand factors or institutional decisions on the tradable permits market. Contrary to the existing literature, we show that the stochastic process of carbon futures prices does not contain a continuous component (Brownian motion). The results are derived by using high-frequency data in the activity signature function framework (Todorov and Tauchen in J Econom 154:125-138, 2010; Todorov and Tauchen in J Bus Econ Stat 29:356-371, 2011). The implication is that the carbon futures price should be modeled as an appropriately sampled, centered Lévy or Poisson process. The pure-jump behavior of the carbon price might be explained by the lower volume of trades on this allowance market (compared to other highly liquid financial markets). © 2013 Springer Science+Business Media Dordrecht.

Rossi F.,Aix - Marseille University | Colaneri P.,Polytechnic of Milan | Shorten R.,National University of Ireland
IEEE Transactions on Automatic Control | Year: 2011

This technical note has been motivated by the need to assess the preservation of polyhedral Lyapunov functions for stable continuous-time linear systems under numerical discretization of the transition matrix. This problem arises when discretizing linear systems in such a manner as to preserve a certain type of stability of the discrete time approximation. Our main contribution is to show that a continuous-time system and its Padé discretization (of any order and sampling) always share at least one common piecewise linear (polyhedral) Lyapunov function. © 2011 IEEE.

Wenger J.,Aix - Marseille University
International Journal of Optics | Year: 2012

Plasmonic antennas offer promising opportunities to control the emission of quantum objects. As a consequence, the fluorescence enhancement factor is widely used as a figure of merit for a practical antenna realization. However, the fluorescence enhancement factor is not an intrinsic property of the antenna. It critically depends on several parameters, some of which are often disregarded. In this contribution, I explore the influence of the setup collection efficiency, emitter's quantum yield, and excitation intensity. Improperly setting these parameters may significantly alter the enhancement values, leading to potential misinterpretations. The discussion is illustrated by an antenna example of a nanoaperture surrounded by plasmonic corrugations. © 2012 Jérme Wenger.

Mondal S.,Aix - Marseille University
Chemical Reviews | Year: 2012

A study was conducted to demonstrate the latest developments in the synthesis and application of sultones. It was demonstrated that several researchers were investigating sultone chemistry, as sultones were synthetically useful heterocycles in organic synthesis. Many powerful methodologies were developed for the synthesis of the sultones, such as intramolecular Diels-Alder reactions, ring-closing metathesis, Pd-catalyzed intramolecular coupling reactions, Rh-catalyzed C-H insertion, and Rh-catalyzed carbene cyclization cycloaddition cascade reactions. The syntheses of sultones have been divided into two categories for better understanding, such as asymmetric synthesis and nonasymmetric synthesis. Asymmetric syntheses of sultones became an attractive goal for the researchers, as chiral sultones offered novel possibilities for stereoselective transformations.

Pellissier H.,Aix - Marseille University
Advanced Synthesis and Catalysis | Year: 2012

Since about the year 2000, the research area of asymmetric organocatalysis has grown rapidly to become one of the most fascinating and current fields in organic chemistry. In the last years, asymmetric domino reactions have widely benefited from this fast-growing field, as exemplified by the development of an explosive number of novel and powerful asymmetric organocatalytic domino processes, which allowed the easy construction of complex chiral molecular architectures from simple materials with high yields and very often remarkable enantioselectivities in a metal-free environment. Indeed, the possibility to join two or more organocatalytic reactions in one asymmetric domino process has become a challenging goal for chemists, due to several advantages from economical and environmental points of view, avoiding costly protecting groups and time-consuming purification procedures after each step, for example. This review aims to update the latest developments of this hot and fascinating field, covering the literature since the beginning of 2009. Abbreviations: Ac: acetyl; Ar: aryl; BDHP: 1,1′-binaphth-2,2′-diyl hydrogen phosphate; BA: Brønsted acid; BINAPO: 2-diphenylphosphino-2′-diphenylphosphinyl-1, 1′-binaphthalene; BINOL: 1,1′-bi-2-naphthol; Boc: tert-butoxycarbonyl; Bn: benzyl; Bu: butyl; Bz: benzoyl; CSA: camphorsulfonic acid; Cy: cyclohexyl; Cbz: benzyloxycarbonyl; DABCO: 1,4-diazabicyclo[2.2.2] octane; DBU: 1,8-diazabicyclo[5.4.0]undec-7-ene; DCE: dichloroethane; de: diastereomeric excess; DFT: density functional theory; DHQ: hydroquinine; DHQD: dihydroquinidine; DIPEA: diisopropylethylamine; DKR: dynamic kinetic resolution; DMAD: dimethyl acetylenedicarboxylate; E: electrophile; ee: enantiomeric excess; ESI: electrospray ionization; Et: ethyl; Fu: furyl; Hept: heptyl; Hex: hexyl; HOMO: highest occupied molecular orbital; IBX: o-iodoxybenzoic acid; LB: Lewis base; LUMO: lowest unoccupied molecular orbital; Me: methyl; MOM: methoxymethyl; Mes: mesyl; MS: mass spectroscopy; MTBE: methyl tert-butyl ether; NADH: nicotinamide adenine dinucleotide; Naph: naphthyl; NHC: N-heterocyclic carbene; NMM: N-methylmorpholine; NMP: N-methylpyrrolidinone; Ns: nosyl; Nu: nucleophile; Oct: octyl; PCC: pyridinium chlorochromate; Pent: pentyl; PFBA: pentafluorobenzoic acid; Ph: phenyl; PMB: para-methoxybenzyl; Pr: propyl; Py: pyridine; r.t.: room temperature; TBA: tribromoacetic acid; TBS: tert-butyldimethylsilyl; TCBA: 2,4,6-trichlorobenzoic acid; TES: triethylsilyl; TFA: trifluoroacetic acid; THF: tetrahydrofuran; Thio: thiophene; TMEDA: tetramethylethylenediamine; TMS: trimethylsilyl; Tol: tolyl; Ts: 4-toluenesulfonyl (tosyl). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Darmon P.,Sainte Marguerite University Hospital | Darmon P.,Aix - Marseille University
Current Opinion in Clinical Nutrition and Metabolic Care | Year: 2013

PURPOSE OF REVIEW: Strategies for weight management in older adults remain controversial as overweight may protect them against mortality whereas weight loss may have harmful effects by promoting sarcopenia and bone loss. It has been suggested that weight management for obese older adults should focus more on maintaining weight and improving physical function than promoting weight loss. This review aims to specify whether intentional weight loss in older adults is a useful or a wasting disease generating strategy. RECENT FINDINGS: Recent randomized controlled studies have shown that a supervised, moderate caloric restriction coupled with regular exercise (both aerobic and resistance) in obese older adults do not increase mortality risk and may conversely reduce insulin resistance, metabolic complications, and disabilities without exacerbating lean mass and bone mineral density loss. SUMMARY: In obese older adults, moderate weight loss may have beneficial effects on comorbidities, functional performances, and quality of life provided that regular physical activity can be associated. An individual approach considering life expectancy, chronic comorbidities, functional status, personal motivation, and social support should be preferred. More research is needed to define the circumstances in which cautious dietary restrictions are reasonably justified in older adults. In any case, in the oldest (≥80 years) as in frail individuals, it seems reasonable to abstain from recommending weight loss. © 2013 Wolters Kluwer Health | Lippincott Williams &Wilkins.

Rovelli C.,Aix - Marseille University | Vidotto F.,Radboud University Nijmegen
International Journal of Modern Physics D | Year: 2014

Quantum-gravitational pressure can stop gravitational collapse and cause a bounce. We observe that: (i) due to the huge time dilation, the process can last micro-seconds in local proper time and billions of years observed from the outside; (ii) the bounce volume can be much larger than planckian, because the onset of quantum-gravity effects is governed by density, not size; (iii) the emerging object can then be bigger than planckian by a factor (m/mP)n, where m is the initial mass, mP is the Planck mass, and n positive; (iv) the interior of an evaporating hole can keep memory of the initial mass, providing an independent scale for the physics of the final explosion. If so, primordial black holes could produce a detectable signal of quantum gravitational origin, which we estimate, under some hypotheses, around the wavelength 10-14 cm. © 2014 World Scientific Publishing Company.

Vangkilde S.,Copenhagen University | Coull J.T.,Aix - Marseille University | Bundesen C.,Copenhagen University
Journal of Experimental Psychology: Human Perception and Performance | Year: 2012

In a crowded dynamic world, temporal expectations guide our attention in time. Prior investigations have consistently demonstrated that temporal expectations speed motor behavior. We explore effects of temporal expectation on perceptual speed in three nonspeeded, cued recognition paradigms. Different hazard rate functions for the cue-stimulus foreperiod were used to manipulate temporal expectations. By computational modeling we estimated two distinct components of visual attention: the temporal threshold of conscious perception (to ms) and the speed of subsequent encoding into visual short-term memory (v items/s). Notably, these components were measured independently of any motor involvement. The threshold to was unaffected by temporal expectation, but perceptual processing speed v increased with increasing expectation. By employing constant hazard rates to keep expectation constant over time, we further confirmed that the increase in perceptual speed was independent of the cue-stimulus duration. Thus, our results strongly suggest temporal expectations optimize perceptual performance by speeding information processing. © 2012 American Psychological Association.

Penin A.,Aix - Marseille University | Lacasa F.,University Paris - Sud | Aghanim N.,University Paris - Sud
Monthly Notices of the Royal Astronomical Society | Year: 2014

Using a full analytical computation of the bispectrum based on the halo model together with the halo occupation number, we derive the bispectrum of the cosmic infrared background (CIB) anisotropies that trace the clustering of dusty-star-forming galaxies. We focus our analysis on wavelengths in the far-infrared and the sub-millimeter typical of the Planck/HFI and Herschel/SPIRE instruments, 350, 550, 850 and 1380 μm. We explore the bispectrum behaviour as a function of several models of evolution of galaxies and show that it is strongly sensitive to that ingredient. Contrary to the power spectrum, the bispectrum, at the four wavelengths, seems dominated by low-redshift galaxies. Such a contribution can be hardly limited by applying low flux cuts. We also discuss the contributions of halo mass as a function of the redshift and the wavelength, recovering that each term is sensitive to a different mass range. Furthermore, we show that the CIB bispectrum is a strong contaminant of the cosmic microwave background bispectrum at 850 μm and higher. Finally, a Fisher analysis of the power spectrum, bispectrum alone and of the combination of both shows that degeneracies on the halo occupation distribution parameters are broken by including the bispectrum information, leading to tight constraints even when including foreground residuals. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

Pelloux Y.,Aix - Marseille University | Murray J.E.,University of Cambridge | Everitt B.J.,University of Cambridge
Psychopharmacology | Year: 2015

Background: The availability of alternative reinforcement has been shown to reduce drug use, but it remains unclear whether it facilitates a reduction or cessation of drug seeking or taking. Objectives: We compared the effects of punishment of cocaine seeking or taking behaviour after brief or extended cocainetaking histories when behavioural reallocation was facilitated or not by making available an alternative ingestive reinforcer (sucrose). Methods: In the first experiment, punishment of either seeking or taking responses was introduced immediately after training on the seeking-taking chained schedule. In the second experiment, punishment of cocaine seeking was introduced after 12 additional days of either 1 or 6 h daily access to cocaine selfadministration. In both experiments, beginning 1 week before the introduction of punishment, a subset of rats had concurrent nose poke access to sucrose while seeking or taking cocaine. Results: The presence of an alternative source of reinforcement markedly facilitated behavioural reallocation from punished cocaine taking after acquisition. It also facilitated punishment-induced suppression of cocaine seeking after an extensive cocaine self-administration history likely by prompting goal-directed motivational control over drug use. However, a significant proportion of rats were deemed compulsive - maintaining drug use after an extensive cocaine history despite the presence of abstinence-promoting positive and negative incentives. Conclusion: Making available an alternative reinforcer facilitates disengagement from punished cocaine use through at least two different processes but remains ineffective in a subpopulation of vulnerable animals, which continued to seek cocaine despite the aversive consequence of punishment and the presence of the alternative positive reinforcer. © The Author(s) 2014.

Roques L.,French National Institute for Agricultural Research | Cristofol M.,Aix - Marseille University
Nonlinearity | Year: 2010

This paper is devoted to the analysis of some uniqueness properties of a classical reaction-diffusion equation of the Fisher-KPP type, coming from population dynamics in heterogeneous environments. We work in a one-dimensional interval (a, b) and we assume a nonlinear term of the form u (μ(x) - γu) where μ belongs to a fixed subset of C0([a, b]). We prove that the knowledge of u at t = 0 and of u, ux at a single point x0 and for small times t ∈ (0, ε) is sufficient to completely determine the couple (u(t, x), μ(x)) provided γ is known. Additionally, if uxx(t, x0) is also measured for t ∈ (0, ε), the triplet (u(t, x), μ(x), γ) is also completely determined. Those analytical results are completed with numerical simulations which show that, in practice, measurements of u and ux at a single point x0 (and for t ∈ (0, ε)) are sufficient to obtain a good approximation of the coefficient μ(x). These numerical simulations also show that the measurement of the derivative ux is essential in order to accurately determine μ(x). © 2010 IOP Publishing Ltd and London Mathematical Society.

Lacasa F.,University Paris - Sud | Penin A.,Aix - Marseille University | Aghanim N.,University Paris - Sud
Monthly Notices of the Royal Astronomical Society | Year: 2014

We present the first halo model based description of the cosmic infrared background (CIB) non-Gaussianity (NG) that is fully parametric. To this end, we introduce, for the first time, a diagrammatic method to compute high order polyspectra of the 3D galaxy density field. It allows an easy derivation and visualization of the different terms of the polyspectrum. We apply this framework to the power spectrum and bispectrum, and we show how to project them on the celestial sphere in the purpose of the application to the CIB angular anisotropies. Furthermore, we show how to take into account the particular case of the shot noise terms in that framework. Eventually, we compute the CIB angular bispectrum at 857 GHz and study its scale and configuration dependences, as well as its variations with the halo occupation distribution parameters. Compared to a previously proposed empirical prescription, such physically motivated model is required to describe fully the CIB anisotropies bispectrum. Finally, we compare the CIB bispectrum with the bispectra of other signals potentially present at microwave frequencies, which hints that detection of CIB NG should be possible above 220 GHz. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

Lacour M.,Aix - Marseille University
Journal of Vestibular Research: Equilibrium and Orientation | Year: 2013

Betahistine dihydrochloride (betahistine) is currently used in the management of vertigo and vestibular pathologies with different aetiologies. The main goal of this review is to clarify the mechanisms of action of this drug, responsible for the symptomatic relief of vertigo and the improvement of vestibular compensation. The review starts with a brief summary recalling the role of histamine as a neuromodulator/neurotransmitter in the control of the vestibular functions, and the role of the histaminergic system in vestibular compensation. Then are presented data recorded in animal models demonstrating that betahistine efficacy can be explained by mechanisms targeting the histamine receptors (HRs) at three different levels: the vascular tree, with an increase of cochlear and vestibular blood flow involving the H1R; the central nervous system, with an increase of histamine turnover implicating the H3R, and the peripheral labyrinth, with a decrease of vestibular input implying the H3R/H4R. Clinical data from vestibular loss patients show the impact of betahistine treatment for the long-term control of vertigo, improvement of balance and quality of life that can be explained by these mechanisms of action. However, two conditions, at least, are required for reaching the betahistine therapeutic effect: the dose and the duration of treatment. Experimental and clinical data supporting these requirements are exposed in the last part of this review. © 2013-IOS Press and the authors.

Fanciullino R.,La Conception University Hospital of Marseille | Ciccolini J.,Aix - Marseille University | Milano G.,Oncopharmacology Unit
Critical Reviews in Oncology/Hematology | Year: 2013

Improving the efficacy-toxicity balance of anticancer agents remains an ongoing challenge in oncology. Beside the ever-growing development of innovative drugs addressing newly discovered molecular targets, nanotechnologies provide today a promising and exciting strategy to achieve this goal. The idea of carrying active compounds to their respective targets so as to improve their efficacy while sparing healthy tissue and reducing side-effects is not new. However, this area of research is in constant rise, and benefits from the latest advances in the field of biopharmaceutics, medicinal chemistry and nanomedicine. In addition to anthracyclines already widely present as liposomal drugs on the shelves, a variety of anticancer drugs can be now encapsulated into different chemical of structures so as to enhance their specificity toward malignant cells, mainly through improved pharmacokinetics profiles. Indeed, the recent advances in chemistry allow now a wide variety of scaffolds to be used as drug-carriers, so as optimize the delivery of cytotoxics. Even more recently, conjugated-drugs such as nanoalbumin (Nab) conjugates have emerged as a new promising alternative to improve both anticancer drugs distribution in the body and efficacy/toxicity balance eventually. This review covers the achievements and current limits of nanoparticles in oncology, with a special focus on nab-paclitaxel as a paradigmatic drug for this new generation of conjugated entities. © 2013 Elsevier Ireland Ltd.

Giletti T.,Aix - Marseille University
Nonlinearity | Year: 2010

We consider in this paper a reaction-diffusion system in the presence of a flow and under a KPP hypothesis. While the case of a single-equation has been extensively studied since the pioneering Kolmogorov-Petrovski- Piskunov paper, the study of the corresponding system with a Lewis number not equal to 1 is still quite open. Here, we will prove some results about the existence of travelling fronts and generalized travelling fronts solutions of such a system with the presence of a nonlinear space-dependent loss term inside the domain. In particular, we will point out the existence of a minimal speed, above which any real value is an admissible speed. We will also give some spreading results for initial conditions decaying exponentially at infinity. © 2010 IOP Publishing Ltd & London Mathematical Society.

Abdel M.P.,Mayo Medical School | Oussedik S.,University College London | Parratte S.,Aix - Marseille University | Lustig S.,Lyon University Hospital Center | Haddad F.S.,22 Buckingham Street
Bone and Joint Journal | Year: 2014

Substantial healthcare resources have been devoted to computer navigation and patientspecific instrumentation systems that improve the reproducibility with which neutral mechanical alignment can be achieved following total knee replacement (TKR). This choice of alignment is based on the long-held tenet that the alignment of the limb post-operatively should be within 3° of a neutral mechanical axis. Several recent studies have demonstrated no significant difference in survivorship when comparing well aligned versus malaligned TKRs. Our aim was to review the anatomical alignment of the knee, the historical and contemporary data on a neutral mechanical axis in TKR, and the feasibility of kinematicallyaligned TKRs. Review of the literature suggests that a neutral mechanical axis remains the optimal guide to alignment. © 2014 The British Editorial Society of Bone & Joint Surgery.

Jacquemet N.,Paris-Sorbonne University | Joule R.-V.,Aix - Marseille University | Luchini S.,French National Center for Scientific Research | Shogren J.F.,University of Wyoming
Journal of Environmental Economics and Management | Year: 2013

Eliciting sincere preferences for non-market goods remain a challenge due to the discrepency between hypothetical and real behavior and false zeros. The gap arises because people either overstate hypothetical values or understate real commitments or a combination of both. Herein we examine whether the traditional real-world institution of the solemn oath can improve preference elicitation. Applying the social psychology theory on the oath as a truth-telling-commitment device, we ask our bidders to swear on their honour to give honest answers prior to participating in an incentive-compatible second-price auction. The oath is an ancillary mechanism to commit bidders to bid sincerely in a second-price auction. Results from our induced valuation testbed treatments suggest that the oath-only auctions outperform all our other auctions (real and hypothetical). In our homegrown valuation treatments eliciting preferences for dolphin protection, the oath-only design induced people to treat as binding both their experimental budget constraint (i.e., lower values on the high end of the value distribution) and participation constraint (i.e., positive values in place of the zero bids used to opt-out of auction). Based on companion treatments, we show the oath works through an increase in the willingness to tell the truth, due to a strengthening of the intrinsic motivation to do so. © 2012 Elsevier Inc.

Zoghaib L.,Airbus | Mattei P.-O.,Aix - Marseille University
Journal of Sound and Vibration | Year: 2014

A method to compute the non-stationary time and frequency response of structures with a frequency-dependent non-proportional linear damping, called the resonance modes method, is presented in this paper. It consists of two main steps. The first step aims at spotting the structure resonance modes, which are the solutions of the matrix nonlinear eigenvalue problem obtained using the finite element method in the complex plane. This step requires a complex eigensolver and an iterative scheme, a perturbation technique or a combination of both. The second step uses the computed resonance modes and an analytical expression of the inverse Laplace transform to deduce the time or frequency response of structures to general excitations. The response of an aluminum plate damped with an elastomer treatment to a point-force excitation, computed with the classical modal approach, the direct solution and the presented method shows its precision and efficiency. An acoustic power computation finally validates the implementation of a fast variant, based on the perturbation technique, for vibroacoustic applications. © 2013 Elsevier Ltd.

Baffou G.,Aix - Marseille University | Quidant R.,ICFO - Institute of Photonic Sciences | Quidant R.,Catalan Institution for Research and Advanced Studies
Chemical Society Reviews | Year: 2014

Noble metal nanoparticles supporting plasmonic resonances behave as efficient nanosources of light, heat and energetic electrons. Owing to these properties, they offer a unique playground to trigger chemical reactions on the nanoscale. In this tutorial review, we discuss how nanoplasmonics can benefit chemistry and review the most recent developments in this new and fast growing field of research. © 2014 the Partner Organisations.

Bourrely C.,Aix - Marseille University
European Physical Journal C | Year: 2014

In the Bourrely-Soffer-Wu model we introduce for the pomeron a new opaqueness in impact parameter space in terms of different quark contributions described by a Fermi-Dirac distribution. In order to check the validity of this assumption we consider p p, p̄ p, and π± p elastic scattering. We emphasize the role of the gluon above the diffraction peak in the differential cross sections. Once these contributions are determined we extend the model to light nuclei elastic reactions like p d, p 4He and π± 4He. The results obtained show a good description of all these elastic processes over the available experimental energy range and moderate momentum transfer. © 2014 The Author(s).

Dolocan V.O.,Aix - Marseille University
Applied Physics Letters | Year: 2012

The interaction between a spin polarized dc electrical current and spin wave modes of a cylindrical nanowire is investigated in this report. We found that close to the critical current, the uniform mode is suppressed, while the edge mode starts to propagate into the sample. When the current exceeds the critical value, this phenomenon is even more accentuated. The edge mode becomes the uniform mode of the nanowire. The higher spin wave modes are slowly pushed away by the current until the propagating mode remains. © 2012 American Institute of Physics.

Chinot O.L.,Aix - Marseille University | Wick W.,German Cancer Research Center | Mason W.,Princess Margaret Hospital | Henriksson R.,Regional Cancer Center | And 12 more authors.
New England Journal of Medicine | Year: 2014

BACKGROUND: Standard therapy for newly diagnosed glioblastoma is radiotherapy plus temozolomide. In this phase 3 study, we evaluated the effect of the addition of bevacizumab to radiotherapy-temozolomide for the treatment of newly diagnosed glioblastoma. METHODS: We randomly assigned patients with supratentorial glioblastoma to receive intravenous bevacizumab (10 mg per kilogram of body weight every 2 weeks) or placebo, plus radiotherapy (2 Gy 5 days a week; maximum, 60 Gy) and oral temozolomide (75 mg per square meter of body-surface area per day) for 6 weeks. After a 28-day treatment break, maintenance bevacizumab (10 mg per kilogram intravenously every 2 weeks) or placebo, plus temozolomide (150 to 200 mg per square meter per day for 5 days), was continued for six 4-week cycles, followed by bevacizumab monotherapy (15 mg per kilogram intravenously every 3 weeks) or placebo until the disease progressed or unacceptable toxic effects developed. The coprimary end points were investigator-assessed progression-free survival and overall survival. RESULTS: A total of 458 patients were assigned to the bevacizumab group, and 463 patients to the placebo group. The median progression-free survival was longer in the bevacizumab group than in the placebo group (10.6 months vs. 6.2 months; stratified hazard ratio for progression or death, 0.64; 95% confidence interval [CI], 0.55 to 0.74; P<0.001). The benefit with respect to progression-free survival was observed across subgroups. Overall survival did not differ significantly between groups (stratified hazard ratio for death, 0.88; 95% CI, 0.76 to 1.02; P = 0.10). The respective overall survival rates with bevacizumab and placebo were 72.4% and 66.3% at 1 year (P = 0.049) and 33.9% and 30.1% at 2 years (P = 0.24). Baseline health-related quality of life and performance status were maintained longer in the bevacizumab group, and the glucocorticoid requirement was lower. More patients in the bevacizumab group than in the placebo group had grade 3 or higher adverse events (66.8% vs. 51.3%) and grade 3 or higher adverse events often associated with bevacizumab (32.5% vs. 15.8%). CONCLUSIONS: The addition of bevacizumab to radiotherapy-temozolomide did not improve survival in patients with glioblastoma. Improved progression-free survival and maintenance of baseline quality of life and performance status were observed with bevacizumab; however, the rate of adverse events was higher with bevacizumab than with placebo. Copyright © 2014 Massachusetts Medical Society.

Lefevre J.,Aix - Marseille University | Lefevre J.,CEA Saclay Nuclear Research Center | Mangin J.-F.,CEA Saclay Nuclear Research Center
PLoS Computational Biology | Year: 2010

Cortical folding exhibits both reproducibility and variability in the geometry and topology of its patterns. These two properties are obviously the result of the brain development that goes through local cellular and molecular interactions which have important consequences on the global shape of the cortex. Hypotheses to explain the convoluted aspect of the brain are still intensively debated and do not focus necessarily on the variability of folds. Here we propose a phenomenological model based on reaction-diffusion mechanisms involving Turing morphogens that are responsible for the differential growth of two types of areas, sulci (bottom of folds) and gyri (top of folds). We use a finite element approach of our model that is able to compute the evolution of morphogens on any kind of surface and to deform it through an iterative process. Our model mimics the progressive folding of the cortical surface along foetal development. Moreover it reveals patterns of reproducibility when we look at several realizations of the model from a noisy initial condition. However this reproducibility must be tempered by the fact that a same fold engendered by the model can have different topological properties, in one or several parts. These two results on the reproducibility and variability of the model echo the sulcal roots theory that postulates the existence of anatomical entities around which the folding organizes itself. These sulcal roots would correspond to initial conditions in our model. Last but not least, the parameters of our model are able to produce different kinds of patterns that can be linked to developmental pathologies such as polymicrogyria and lissencephaly. The main significance of our model is that it proposes a first approach to the issue of reproducibility and variability of the cortical folding. © 2010 Lefèvre, Mangin.

Goubard F.,Cergy-Pontoise University | Dumur F.,Aix - Marseille University
RSC Advances | Year: 2015

Truxene (10,15-dihydro-5H-diindeno[1,2-a;1′,2′-c]fluorene), which is a heptacyclic polyarene structure, has attracted a great deal of interest due to its exceptional solubility, high thermal stability and ease with which it may be modified. Over the years and thanks to the advances in the synthesis of truxene derivatives, the scope of applications of this attractive building block, initially limited to synthesis and photoluminescence, has nowadays been extended to organic electronics. This review aims at highlighting the benefits brought by the introduction of this rigid star-shaped molecule in different materials. Perspectives for this highly appealing molecule in future research will also be put forth. © The Royal Society of Chemistry 2015.

The Mediterranean coast has been significantly modified by human interventions, especially over the last two centuries, and large stretches are now subject to geomorphic instability. The numerous dams constructed for agricultural and hydroelectric purposes and river channel modifications over the last two centuries have affected many of the Mediterranean rivers, commonly generating drastic reductions in sediment inputs necessary for maintaining dynamic beach and dune systems. Large stretches of shoreline and commonly narrow coastal plains have also been massively engineered. These shoreline modifications have been notably associated with the construction of marinas, leisure harbours and artificial beaches, and have resulted in the emergence of veritable artificial shorelines. Rocky shores in the Mediterranean are also being subjected to increasing pressures from housing and tourism. Future sustainable development of the Mediterranean coast will require a clear identification of the stakes and a better re-evaluation of management strategies.

Lopez C.,Aix - Marseille University
Multisensory Research | Year: 2015

The role of the vestibular system in posture and eye movement control has been extensively described. By contrast, how vestibular signals contribute to bodily perceptions is a more recent research area in the field of cognitive neuroscience. In the present review article, I will summarize recent findings showing that vestibular signals play a crucial role in making sense of the body. First, data will be presented showing that vestibular signals contribute to bodily perceptions ranging from low-level bodily perceptions, such as touch, pain, and the processing of the bodys metric properties, to higher level bodily perceptions, such as the sense of owning a body, the sense of being located within this body (embodiment), and the anchoring of the visuo-spatial perspective to this body. In the second part of the review article, I will show that vestibular information seems to be crucially involved in the visual perception of biological motion and in the visual perception of human body structure. Reciprocally, observing human bodies in motion influences vestibular self-motion perception, presumably due to sensorimotor resonance between the self and others. I will argue that recent advances in the mapping of the human vestibular cortex afford neuroscientific models of the vestibular contributions to human bodily self-consciousness. © Copyright 2015 by Koninklijke Brill NV, Leiden, The Netherlands.

Castelnuovo M.,iGE3 | Castelnuovo M.,Aix - Marseille University | Stutz F.,iGE3
Current Opinion in Cell Biology | Year: 2015

The number and variety of factors underlying control of gene expression have been frequently underestimated. Non-coding RNAs generated through pervasive transcription have recently been implicated in shaping the transcriptional landscape in different organisms from bacteria to higher eukaryotes, adding a previously unexpected layer of complexity to the process of gene regulation. In this review, we highlight non-coding transcription-dependent regulatory mechanisms linked to chromatin organization and environmental changes, and particular emphasis is given to single-cell approaches, which have been crucial in dissecting cell-to-cell variability. These studies have revealed that non-coding transcription can underlie the extensive heterogeneity in patterns of gene expression within a cell population. © 2015 Elsevier Ltd.

Rovelli C.,Aix - Marseille University | Rovelli C.,University of Toulon | Vidotto F.,Radboud University Nijmegen
Physical Review Letters | Year: 2013

A simple argument indicates that covariant loop gravity (spin foam theory) predicts a maximal acceleration and hence forbids the development of curvature singularities. This supports the results obtained for cosmology and black holes using canonical methods. © 2013 American Physical Society.

Eloy C.,University of California at San Diego | Eloy C.,Aix - Marseille University
Journal of Fluids and Structures | Year: 2012

To evaluate the swimming performances of aquatic animals, an important dimensionless quantity is the Strouhal number, St = fA/. U, with f the tail-beat frequency, A the peak-to-peak tail amplitude, and U the swimming velocity. Experiments with flapping foils have exhibited maximum propulsive efficiency in the interval 0.25 < St < 0.35 and it has been argued that animals likely evolved to swim in the same narrow interval. Using Lighthill's elongated-body theory to address undulatory propulsion, it is demonstrated here that the optimal Strouhal number increases from 0.15 to 0.8 for animals spanning from the largest cetaceans to the smallest tadpoles. To assess the validity of this model, the swimming kinematics of 53 different species of aquatic animals have been compiled from the literature and it shows that their Strouhal numbers are consistently near the predicted optimum. © 2012 Elsevier Ltd.

Bourrely C.,Aix - Marseille University | Buccella F.,National Institute of Nuclear Physics, Italy | Soffer J.,Temple University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2013

We consider W± gauge bosons production in connection with recent results from BNL-RHIC and FNAL-Tevatron and interesting predictions from the statistical parton distributions. They concern relevant aspects of the structure of the nucleon sea and the high-x region of the valence quark distributions. We also give predictions in view of future proton-neutron collisions experiments at BNL-RHIC. © 2013 Elsevier B.V.

Farhat M.,King Abdullah University of Science and Technology | Guenneau S.,Aix - Marseille University | Bagci H.,King Abdullah University of Science and Technology
Physical Review Letters | Year: 2013

We propose a concept that allows for efficient excitation of surface plasmon spolaritons (SPPs) on a thin graphene sheet located on a substrate by an incident electromagnetic field. Elastic vibrations of the sheet, which are generated by a flexural wave, act as a grating that enables the electromagnetic field to couple to propagating graphene SPPs. This scheme permits fast on-off switching of the SPPs and dynamic tuning of their excitation frequency by adjusting the vibration frequency (grating period). Potential applications include single molecule detection and enhanced control of SPP trajectories via surface wave patterning of graphene metasurfaces. Analytical calculations and numerical experiments demonstrate the practical applicability of the proposed concept. © 2013 American Physical Society.

Bonami P.,Aix - Marseille University
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2011

This paper addresses the problem of generating cuts for mixed integer nonlinear programs where the objective is linear and the relations between the decision variables are described by convex functions defining a convex feasible region. We propose a new method for strengthening the continuous relaxations of such problems using cutting planes. Our method can be seen as a practical implementation of the lift-and-project technique in the nonlinear case. To derive each cut we use a combination of a nonlinear programming subproblem and a linear outer approximation. One of the main features of the approach is that the subproblems solved to generate cuts are typically not more complicated than the original continuous relaxation. In particular they do not require the introduction of additional variables or nonlinearities. We propose several strategies for using the technique and present preliminary computational evidence of its practical interest. In particular, the cuts allow us to improve over the state of the art branch-and-bound of the solver Bonmin, solving more problems in faster computing times on average. © 2011 Springer-Verlag.

La Scola B.,Aix - Marseille University | La Scola B.,Institut Universitaire de France
Microbial Pathogenesis | Year: 2014

In the environment, protozoa are predators of bacteria and feed on them. The possibility that some protozoa could be a source of human pathogens is consistent with the discovery that free-living amoebae were the reservoir of Legionella pneumophila, the agent of Legionnaires' disease. Later, while searching for Legionella in the environment using amoeba co-culture, the first giant virus, Acanthamoeba polyphaga mimivirus, was discovered. Since then, many other giant viruses have been isolated, including Marseilleviridae, Pithovirus sibericum, Cafeteria roenbergensis virus and Pandoravirus spp. The methods used to isolate all of these viruses are herein reviewed. By analogy to Legionella, it was originally suspected that these viruses could be human pathogens. After showing by indirect evidence, such as sero-epidemiologic studies, that it was possible for these viruses to be human pathogens, the recent isolation of some of these viruses (belonging to the Mimiviridae and Marseilleviridae families) in humans in the context of pathologic conditions shows that they are opportunistic human pathogens in some instances. © 2014 Elsevier Ltd.

Richet H.,Aix - Marseille University
Clinical Microbiology and Infection | Year: 2012

To assess seasonal variations in Gram-negative and healthcare-associated infections (HCAIs), a literature search was performed with combinations of the keywords 'seasonality', 'seasonal variations', 'Gram-negative bacilli', 'infections', 'nosocomial infections', and 'health care associated infections', to retrieve articles published in English in peer-reviewed journals from 1 January 1970 to 29 February 2012. Seasonality was demonstrated for infections, mostly bloodstream infections (BSIs), caused by Acinetobacter spp., Escherichia coli, Enterobacter cloacae, Klebsiella spp., and Pseudomonas aeruginosa, with higher rates of infection during the summer months in North America, Europe, the Middle East, Australia, and Asia. Correlations were observed between temperature increase and rates of BSI for Acinetobacter spp., P. aeruginosa, E. coli, Klebsiella pneumoniae, and extended-spectrum β-lactamase-producing Enterobacteriaceae. A significant correlation between lower urinary tract infections and higher temperature and decreased relative humidity could explain the seasonality of some BSIs. Regarding HCAI, seasonality is intrinsically present in most viral respiratory and gastrointestinal infections, because viruses are introduced into hospitals during seasonal community outbreaks. Other HCAIs subject to seasonal variations include surgical wound infections, with winter peaks in the USA and summer peaks in Finland, central-line-associated BSIs in haematology/oncology paediatric outpatients, and dialysis-associated peritonitis. In summary, seasonal variations have been shown for infections caused by many Gram-negative bacilli, as well as for a few HCAIs, but many studies remain to be performed in order to better understand the mechanisms of these variations. © 2012 The Author. Clinical Microbiology and Infection © 2012 European Society of Clinical Microbiology and Infectious Diseases.

Roman B.,University Paris Diderot | Pocheau A.,Aix - Marseille University | Pocheau A.,French National Center for Scientific Research
Physical Review Letters | Year: 2012

We address the crumpling of thin sheets in between large scale curved cylinders. In contrast with the usual crushing of a paper ball, one curvature of the sheet is fixed here by the cylinders radius, yielding an anisotropic compaction. As compaction proceeds, it is found that sheets first develop singular folds involving ridges or developable cones, but eventually turn to regular folds free of any geometrical singularities, without ever having entered the plastic regime. This surprising uncrumpling transition corresponds to a stress defocusing. It is understood from a balance between bending and stretching energies on regular states. © 2012 American Physical Society.

The study presented here from the southern French Alps demonstrates the reliability of soil charcoal analysis for the study of Holocene past treeline positions. The occurrence of charcoal in mineral soils along transects from 1950 m up to 2920 m demonstrates the role of fire in the establishment of the present vegetation patterns. The abrupt decrease of charcoal concentration at about 2400-2600 m (which varies across the study sites) corresponds to the modern transition between subalpine forest and alpine tundra. Charcoal particles formed in situ provide high spatial-resolution data for the reconstruction of past forest and treeline changes. Soil charcoal analysis indicated that: (1) treeline was 300 m higher around 6800 cal. BP than today; and (2) the uppermost forest belt up to 2810 m was colonized by larch (Larix decidua Mill.) and arolla pine (Pinus cembra L.). This pine is present today but patchily distributed: it is absent from the three areas studied. Radiocarbon dates, ranging from c. 6800 cal. BP to the modern period, along with historical and archaeological data, suggest that the present pattern of the uppermost forest belt, and the patchy distribution of arolla pine in the studied area are the results of anthropogenic fire (mainly agropastoral activities). The question of global warming consequences on treelines in this part of the French Alps is discussed. © The Author(s), 2010.

Fraysse F.,French National Center for Scientific Research | Pokrovsky O.S.,French National Center for Scientific Research | Meunier J.-D.,Aix - Marseille University
Geochimica et Cosmochimica Acta | Year: 2010

Quantification of silicon and calcium recycling by plants is hampered by the lack of physico-chemical data on reactivity of plant litter in soil environments. We applied a laboratory experimental approach for determining the silica and calcium release rates from litter of typical temperate and boreal plants: pine (Pinus laricio), birch (Betula pubescens), larch (Larix gmelinii), elm (Ulmus laevis Pall.), tree fern (Dicksonia squarrosa), and horsetail (Equisetum arvense) in 0.01 M NaCl solutions, pH of 2-10 and temperature equals to 5, 25 and 40 °C. Open system, mixed-flow reactors equipped with dialysis compartment and batch reactors were used. Comparative measurements were performed on intact larch needles and samples grounded during different time, sterilized or not and with addition or not of sodium azide in order to account for the effect of surface to mass ratio and possible microbiological activity on the litter dissolution rates. Litter degradation results suggest that the silica release rate is independent on dissolved organic carbon release (cell breakdown) which implies the presence of phytoliths in a pure "inorganic" pool not complexed with organic matter. Calcium and DOC are released at the very first stage of litter dissolution while Si concentration increases gradually suggesting the presence of Ca and Si in two different pools. The dry-weight normalized dissolution rate at circum-neutral pH range (approx. 1-10 μmol/gDW/day) is 2 orders of magnitude higher than the rates of Si release from common soil minerals (kaolinite, smectite, illite). Minimal Ca release rates evaluated from batch and mixed-flow reactors are comparable with those of most reactive soil minerals such as calcite and apatite, and several orders of magnitude higher than the dissolution rates of major rock-forming silicates (feldspars, pyroxenes). The activation energy for Si liberation from plant litter is approx. 50 kJ/mol which is comparable with that of surface-controlled mineral dissolutions. It is shown that the Si release rate from the above-ground forest biomass is capable of producing the Si concentrations observed in soil solutions of surficial horizons and contribute significantly to the Si flux from the soil to the river. © 2009 Elsevier Ltd. All rights reserved.

Pellissier H.,Aix - Marseille University
Advanced Synthesis and Catalysis | Year: 2015

This review surveys the recent developments in enantioselective titanium-catalyzed cyanation reactions of carbonyl compounds, covering the literature since the beginning of 2008. It well demonstrates that this reaction constitutes an important tool in organic synthesis, still attracting a considerable interest due to the potential use of enantiopure cyanohydrins as natural products and useful synthetic intermediates in the synthesis of biologically active molecules. Abbreviations: Ac: acetyl; Ar: aryl; BINOL: 1,1′-bi-2-naphthol; BINOLAM: bis(diethylaminomethyl)-1,1'-binaphthol; Bn: benzyl; Cy: cyclohexyl; DFT: density functional theory; DMAP: 4-(dimethylamino)pyridine; ee: enantiomeric excess; Naph: naphthyl; r.t.: room temperature; salen: 1,2-bis(salicylidenamino)ethane; TADDOL: α,α,α',α'-tetraphenyl-2,2-dimethyl-1,3-dioxolane-4,5-dimethanol; TEA: trimethylamine; THF: tetrahydrofuran; TMS: trimethylsilyl; Tol: tolyl. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pellissier H.,Aix - Marseille University
Coordination Chemistry Reviews | Year: 2015

This review provides an update of the recent developments in enantioselective vanadium-catalyzed transformations published since the beginning of 2011. A number of highly efficient reactions have been developed so far among them asymmetric sulfide oxidations, epoxidations, a-hydroxy acid oxidations, but also carbon-carbon bond-forming reactions spanning from cyanations of aldehydes, Friedel-Crafts reactions, Michael additions, oxidative couplings of polycyclic phenols to domino reactions. © 2014 Elsevier B.V.

Nataf D.M.,Australian National University | Cassisi S.,National institute for astrophysics | Athanassoula E.,Aix - Marseille University
Monthly Notices of the Royal Astronomical Society | Year: 2014

We demonstrate that failure to properly account for stellar evolution can bias results in determinations of the spatial morphology of Galactic bulge stars, focusing on the question of whether or not the X-shape is more pronounced among the more metal-rich stars than among the metalpoor stars. We argue that this trend, a result recently claimed by three separate groups, may have been overestimated as it is relatively easier to detect a bimodality in the distance distribution function at higher metallicities. This is due to three factors. First, the intrinsic colour of red clump and red giant stars varies with metallicity, at the level d(V- I)RC/d[M/H] ≈ 0.25 mag dex-1, and thus the ratio of red clump to red giant stars within a spectroscopic sample will depend on the photometric selection of any investigation. Secondly, the duration of ascent of the red giant branch goes down and the red clump lifetime goes up as metallicity increases, which has the effect of increasing the ratio of red clump to red giant stars by as much as ~33 per cent over the range of the bulge metallicity distribution function. Finally, over the same metallicity interval, the effective number of red giant branch bump stars is predicted to increase by ~200 per cent, and their presence becomes degenerate with the observational parameters of the two red clumps, creating an illusory increase in signal to noise for a second peak in the distance modulus distribution.© 2014 The Authors.

Lefevre C.T.,Communications nergie Atom Et Aux Energies Altern Center National Of La Rech Scient Aix Mars University | Wu L.-F.,Aix - Marseille University
Trends in Microbiology | Year: 2013

There are few examples of protein- and lipid-bounded organelles in bacteria that are encoded by conserved gene clusters and lead to a specific function. The magnetosome chain represents one of these rare examples and is responsible for magnetotaxis in magnetotactic bacteria (MTB), a behavior thought to aid in finding their optimal growth conditions. The origin and evolution of the magnetotaxis is still a matter of debate. Recent breakthroughs in isolation, cultivation, single-cell separation, and whole-genome sequencing have generated abundant data that give new insights into the biodiversity and evolution of MTB. © 2013 Elsevier Ltd.

Integrated coastal zone management has evolved in practice and in the literature to implicate and advocate for public participation. Public participation has been proposed to open debate, contribute to policy formulation, increase government accountability, build support for agency programs, reduce community tensions and increase the sustainability of the actions. This study analysed the success of three integrated coastal zone management projects based on 8 process and output indicators. Public participation does not seem to have had an impact on the overall project objective nor on the sustainability indicators. These results bring us back to the initial concept of ICZM based on horizontal and vertical integration, and suggest that projects promoting ICZM need to be adapted to each specific cultural and political context. Long-term sustainability and natural resource management will only be achieved when the projects and activities are adapted to meet the reality on the field. © 2010 Elsevier Ltd.

Morvan D.,Aix - Marseille University
Combustion Science and Technology | Year: 2014

The subject of this article concerns the unsteady effects (fire intensity, wind) upon the propagation and, more generally, the behavior of surface fires in open fields. The study focused on two sources of unsteadiness: the first one resulting from the regime of propagation (wind driven or plume dominated), which can affect greatly the behavior of the flame front and consequently the fire intensity, the second one resulting from the wind gusts associated with the conditions of flow of wind in real conditions. The study was based on numerical simulations, using a multiphase formulation, and on spectral analysis of the time evolution of the fire line intensity. The calculations were performed in 2D for a homogeneous vegetation layer (grassland) and for a large interval of wind conditions (10 m open wind velocity U10 ranged between 1 m/s and 25 m/s). The results have highlighted the link between the unsteady character of flame front behavior and the regime of propagation (plume dominated, wind driven). A particular interest was focused on the role played by two potential sources of instabilities, namely the Kelvin-Helmholtz instability (wind effects) and the thermo-convective instability (plume effects), upon the behavior of fires. A second set of simulations has been carried out using unsteady wind conditions, reproduced using sinusoidal boundary conditions for the streamwise velocity, with a frequency ranging between 0.5 Hz and 3 Hz. © Copyright © Taylor & Francis Group, LLC.

Eloy C.,University of California at San Diego | Eloy C.,Aix - Marseille University | Lauga E.,University of California at San Diego
Physical Review Letters | Year: 2012

In a variety of biological processes, eukaryotic cells use cilia to transport flow. Although cilia have a remarkably conserved internal molecular structure, experimental observations report very diverse kinematics. To address this diversity, we determine numerically the kinematics and energetics of the most efficient cilium. Specifically, we compute the time-periodic deformation of a wall-bound elastic filament leading to transport of a surrounding fluid at minimum energetic cost, where the cost is taken to be the positive work done by all internal molecular motors. The optimal kinematics are found to strongly depend on the cilium bending rigidity through a single dimensionless number, the Sperm number, and closely resemble the two-stroke ciliary beating pattern observed experimentally. © 2012 American Physical Society.

Gouin H.,Aix - Marseille University
Colloids and Surfaces A: Physicochemical and Engineering Aspects | Year: 2011

The water ascent in tall trees is subject to controversy: the vegetal biologists debate on the validity of the cohesion-tension theory which considers strong negative pressures in microtubes of xylem carrying the crude sap. This article aims to point out that liquids are submitted at the walls to intermolecular forces inferring density gradients making heterogeneous liquid layers and therefore disqualifying the Navier-Stokes equations for nanofilms. The crude sap motion takes the disjoining pressure gradient into account and the sap flow dramatically increases such that the watering of nanolayers may be analogous to a microscopic flow. Application to microtubes of xylem avoids the problem of cavitation and enables us to understand why the ascent of sap is possible for very high trees. © 2011 Elsevier B.V.

Natoli G.,Italian National Cancer Institute | Andrau J.-C.,Aix - Marseille University | Andrau J.-C.,French Institute of Health and Medical Research | Andrau J.-C.,French National Center for Scientific Research
Annual Review of Genetics | Year: 2012

Mammalian genomes are extensively transcribed outside the borders of protein-coding genes. Genome-wide studies recently demonstrated that cis-regulatory genomic elements implicated in transcriptional control, such as enhancers and locus-control regions, represent major sites of extragenic noncoding transcription. Enhancer-templated transcripts provide a quantitatively small contribution to the total amount of cellular nonribosomal RNA; nevertheless, the possibility that enhancer transcription and the resulting enhancer RNAs may, in some cases, have functional roles, rather than represent mere transcriptional noise at accessible genomic regions, is supported by an increasing amount of experimental data. In this article we review the current knowledge on enhancer transcription and its functional implications. © 2012 by Annual Reviews.

Battesti A.,U.S. National Institutes of Health | Bouveret E.,Aix - Marseille University
Methods | Year: 2012

The bacterial two-hybrid system based on the reconstitution of adenylate cyclase in Escherichia coli (BACTH) was described 14. years ago (Karimova, Pidoux, Ullmann, and Ladant, 1998, PNAS, 95:5752). For microbiologists, it is a practical and powerful alternative to the use of the widely spread yeast two-hybrid technology for testing protein-protein interactions. In this review, we aim at giving the reader clear and most importantly simple instructions that should break any reticence to try the technique. Yet, we also add recommendations in the use of the system, related to its specificities. Finally, we expose the advantages and disadvantages of the technique, and review its diverse applications in the literature, which should help in deciding if it is the appropriate method to choose for the case at hand. © 2012 Elsevier Inc.

Wilson-Ewing E.,Aix - Marseille University | Wilson-Ewing E.,University of Toulon
Journal of Cosmology and Astroparticle Physics | Year: 2013

In the matter bounce scenario, a dust-dominated contracting space-time generates scale-invariant perturbations that, assuming a nonsingular bouncing cosmology, propagate to the expanding branch and set appropriate initial conditions for the radiation-dominated era. Since this scenario depends on the presence of a bounce, it seems appropriate to consider it in the context of loop quantum cosmology where a bouncing universe naturally arises. For a pressureless collapsing universe in loop quantum cosmology, the predicted power spectrum of the scalar perturbations after the bounce is scale-invariant and the tensor to scalar ratio is negligibly small. A slight red tilt can be given to the scale-invariance of the scalar perturbations by a scalar field whose equation of state is P = -ρ, where is a small positive number. Then, the power spectrum for tensor perturbations is also almost scale-invariant with the same red tilt as the scalar perturbations, and the tensor to scalar ratio is expected to be r 9 × 10-4. Finally, for the predicted amplitude of the scalar perturbations to agree with observations, the critical density in loop quantum cosmology must be of the order ρc ∼ 10 -9ρPl. © 2013 IOP Publishing Ltd and Sissa Medialab srl.

Gouin H.,Aix - Marseille University
Journal of Theoretical Biology | Year: 2015

We can propound a thermo-mechanical understanding of the ascent of sap to the top of tall trees thanks to a comparison between experiments associated with the cohesion-tension theory and the disjoining pressure concept for liquid thin-films. When a segment of xylem is tight-filled with crude sap, the liquid pressure can be negative although the pressure in embolized vessels remains positive. Examples are given that illustrate how embolized vessels can be refilled and why the ascent of sap is possible even in the tallest trees avoiding the problem due to cavitation. However, the maximum height of trees is limited by the stability domain of liquid thin-films. © 2015 Elsevier Ltd.

Chrust M.,University of Strasbourg | Bouchet G.,Aix - Marseille University | Duek J.,University of Strasbourg
Physics of Fluids | Year: 2013

We present a comprehensive parametric study of the transition scenario of freely falling discs. The motion of the discs is investigated by a direct numerical simulation of the solid-fluid interaction. The discs are assumed to be homogeneous and infinitely thin. The problem is shown to depend on two independent parameters, the Galileo number expressing the ratio between effects of gravity and viscosity and the non-dimensionalized mass characterizing the inertia of the disc. The obtained results are in agreement with known experimental and numerical data and provide both detailed and comprehensive picture of the transition scenario in the two-parameter plane defined by the Galileo number and the non-dimensionalized mass. © 2013 American Institute of Physics.

Lemarchand F.,Aix - Marseille University
Optics Express | Year: 2014

Refinement techniques usually calculate an optimized local solution, which is strongly dependent on the initial formula used for the thin film design. In the present study, a clustering global optimization method is used which can iteratively change this initial formula, thereby progressing further than in the case of local optimization techniques. A wide panel of local solutions is found using this procedure, resulting in a large range of optical thicknesses. The efficiency of this technique is illustrated by two thin film design problems, in particular an infrared antireflection coating, and a solar-selective absorber coating. © 2014 Optical Society of America.

Lefevre C.T.,Aix - Marseille University | Bazylinskib D.A.,University of Nevada, Las Vegas
Microbiology and Molecular Biology Reviews | Year: 2013

Magnetotactic bacteria (MTB) are widespread, motile, diverse prokaryotes that biomineralize a unique organelle called the magnetosome. Magnetosomes consist of a nano-sized crystal of a magnetic iron mineral that is enveloped by a lipid bilayer membrane. In cells of almost all MTB, magnetosomes are organized as a wellordered chain. The magnetosome chain causes the cell to behave like a motile, miniature compass needle where the cell aligns and swims parallel to magnetic field lines. MTB are found in almost all types of aquatic environments, where they can account for an important part of the bacterial biomass. The genes responsible for magnetosome biomineralization are organized as clusters in the genomes of MTB, in some as a magnetosome genomic island. The functions of a number of magnetosome genes and their associated proteins in magnetosome synthesis and construction of the mag- netosome chain have now been elucidated. The origin of magnetotaxis appears to be monophyletic; that is, it developed in a common ancestor to all MTB, although horizontal gene transfer of magnetosome genes also appears to play a role in their distribution. The purpose of this review, based on recent progress in this field, is focused on the diversity and the ecology of the MTB and also the evolution and transfer of the molecular determinants involved in magnetosome formation. Copyright © 2013, American Society for Microbiology. All Rights Reserved.

Gontero B.,Aix - Marseille University | Maberly S.C.,UK Center for Ecology and Hydrology
Biochemical Society Transactions | Year: 2012

Many proteins contain disordered regions under physiological conditions and lack specific three-dimensional structure. These are referred to as IDPs (intrinsically disordered proteins). CP12 is a chloroplast protein of approximately 80 amino acids and has a molecular mass of approximately 8.2-8.5 kDa. It is enriched in charged amino acids and has a small number of hydrophobic residues. It has a high proportion of disorderpromoting residues, but has at least two (often four) cysteine residues forming one (or two) disulfide bridge(s) under oxidizing conditions that confers some order. However, CP12 behaves like an IDP. It appears to be universally distributed in oxygenic photosynthetic organisms and has recently been detected in a cyanophage. The best studied role of CP12 is its regulation of the Calvin cycle responsible for CO2 assimilation. Oxidized CP12 forms a supramolecular complex with two key Calvin cycle enzymes, GAPDH (glyceraldehyde- 3-phosphate dehydrogenase) and PRK (phosphoribulokinase), down-regulating their activity. Association-dissociation of this complex, induced by the redox state of CP12, allows the Calvin cycle to be inactive in the dark and active in the light. CP12 is promiscuous and interacts with other enzymes such as aldolase and malate dehydrogenase. It also plays other roles in plant metabolism such as protecting GAPDH from inactivation and scavenging metal ions such as copper and nickel, and it is also linked to stress responses. Thus CP12 seems to be involved in many functions in photosynthetic cells and behaves like a jack of all trades as well as being a master of the Calvin cycle. ©The Authors Journal compilation ©2012 Biochemical Society.

Gomez-Diaz C.,University of Lausanne | Reina J.H.,University of Lausanne | Cambillau C.,Aix - Marseille University | Benton R.,University of Lausanne
PLoS Biology | Year: 2013

Pheromones form an essential chemical language of intraspecific communication in many animals. How olfactory systems recognize pheromonal signals with both sensitivity and specificity is not well understood. An important in vivo paradigm for this process is the detection mechanism of the sex pheromone (Z)-11-octadecenyl acetate (cis-vaccenyl acetate [cVA]) in Drosophila melanogaster. cVA-evoked neuronal activation requires a secreted odorant binding protein, LUSH, the CD36-related transmembrane protein SNMP, and the odorant receptor OR67d. Crystallographic analysis has revealed that cVA-bound LUSH is conformationally distinct from apo (unliganded) LUSH. Recombinantly expressed mutant versions of LUSH predicted to enhance or diminish these structural changes produce corresponding alterations in spontaneous and/or cVA-evoked activity when infused into olfactory sensilla, leading to a model in which the ligand for pheromone receptors is not free cVA, but LUSH that is "conformationally activated" upon cVA binding. Here we present evidence that contradicts this model. First, we demonstrate that the same LUSH mutants expressed transgenically affect neither basal nor pheromone-evoked activity. Second, we compare the structures of apo LUSH, cVA/LUSH, and complexes of LUSH with non-pheromonal ligands and find no conformational property of cVA/LUSH that can explain its proposed unique activated state. Finally, we show that high concentrations of cVA can induce neuronal activity in the absence of LUSH, but not SNMP or OR67d. Our findings are not consistent with the model that the cVA/LUSH complex acts as the pheromone ligand, and suggest that pheromone molecules alone directly activate neuronal receptors. © 2013 Gomez-Diaz et al.

Grigor'yan A.,Bielefeld University | Nadirashvili N.,Aix - Marseille University
Archive for Rational Mechanics and Analysis | Year: 2015

We prove a certain upper bound for the number of negative eigenvalues of the Schrödinger operator H = −Δ − V in $${\mathbb{R}^{2}.}$$R2. © 2015, Springer-Verlag Berlin Heidelberg.

Morelli X.,Aix - Marseille University | Hupp T.,University of Edinburgh
EMBO Reports | Year: 2012

The first EMBO workshop on 'Protein-Protein Interaction Analysis & Modulation' took place in June 2012 in Roscoff, France. It brought together researchers to discuss the growing field of protein network analysis and the modulation of protein-protein interactions, as well as outstanding related issues including the daunting challenge of integrating interactomes in systems biology and in the modelling of signalling networks. © 2012 EUROPEAN MOLECULAR BIOLOGY ORGANIZATION.

Kriticos D.J.,CSIRO | Leriche A.,CSIRO | Leriche A.,Aix - Marseille University
Ecography | Year: 2010

Biosecurity agencies are particularly concerned to know the potential distribution of invasive alien species under present, and to a lesser extent, future climates; expensive decisions can hinge upon the degree of perceived threat a pest species poses. Climate-based niche modelling techniques are available to inform these decisions. These tools now regularly employ gridded climate datasets of moderate spatial resolution (0.5 degree), though biosecurity decision-makers continually seek greater spatial precision in the risk map products. Various splining techniques are capable of generating gridded climate datasets approaching the precision limits imposed by the availability of digital elevation model data. As the spatial precision of climate datasets increases, more detailed effects of topographic relief become apparent in the climatic data. When these datasets are used to develop and apply species niche models, the climate data is spatially intersected with species location data to infer relationships between the climate and the species' geographic distribution. Here we investigate the effect of changing climate precision on projections of species' niche models developed with CLIMEX, including the effect of upscaling and downscaling the outputs. We found that there were noticeable increases in sensitivity in models developed using more precise climate datasets. The largest differences in projections were noted where species range limits coincided with regions of strong climatic gradients such as where there was marked topographic relief in relation to the spatial precision of the climatic dataset. Upscaling (fitting a model with a fine resolution dataset and then projecting the results with a coarser grid), tended to produce smaller potential ranges for a species, albeit at the cost of model sensitivity. Downscaling had the opposite effect, identifying additional, mostly marginally climatically suitable habitat. It remains unclear how sensitive the fine resolution results are to the number and spatial arrangement of input location records used to build the model. The results indicate some benefits of improving the spatial resolution of climate datasets, though not at the expense of climatic data accuracy. Decision-makers should be mindful of the inherent uncertainties in these models, and modellers have a responsibility to identify and convey these uncertainties to their intended audience. © 2010 The Author. Journal compilation © 2010 Ecography.

Duchemin L.,Aix - Marseille University | Josserand C.,CNRS Jean Le Rond dAlembert Institute
Physics of Fluids | Year: 2011

We study the influence of the surrounding gas in the dynamics of drop impact on a smooth surface. We use an axisymmetric model for which both the gas and the liquid are incompressible; lubrication regime applies for the gas film dynamics and the liquid viscosity is neglected. In the absence of surface tension a finite time singularity whose properties are analysed is formed and the liquid touches the solid on a circle. When surface tension is taken into account, a thin jet emerges from the zone of impact, skating above a thin gas layer. The thickness of the air film underneath this jet is always smaller than the mean free path in the gas suggesting that the liquid film eventually wets the surface. We finally suggest an aerodynamical instability mechanism for the splash. © 2011 American Institute of Physics.

Lecuit T.,Aix - Marseille University | Yap A.S.,University of Queensland
Nature Cell Biology | Year: 2015

During epithelial morphogenesis, E-cadherin adhesive junctions play an important part in mechanically coupling the contractile cortices of cells together, thereby distributing the stresses that drive cell rearrangements at both local and tissue levels. Here we discuss the concept that cellular contractility and E-cadherin-based adhesion are functionally integrated by biomechanical feedback pathways that operate on molecular, cellular and tissue scales. © 2015 Macmillan Publishers Limited.

de Souto Barreto P.,Aix - Marseille University
Archives of Gerontology and Geriatrics | Year: 2012

Postal survey is a simple and efficient way to collect information in large study samples. The purpose of this study was to find out differences between older adults who responded to a postal survey on health outcomes and those who did not, and to examine the importance of frailty, physical functional decline and poor self-reported health in determining non-response. We mailed out a questionnaire on general health twice at a year's interval to 1000 individuals ≥60 years, and members of the medical insurance scheme of the French national education system. At Year1, 535 persons responded to the questionnaire (65% women, 70.9 ± 8.4 years). A year later (Year2), we obtained 384 responses (63.3% women, 70.5 ± 7.8 years). Compared to respondents, non-respondents at Year2 were more frequently categorized as frail, reported more often to be in bad health, and had more physical functional declines. Frailty, physical functional decline and poor self-reported health increased the likelihood of not responding to Year2 questionnaire, with poor self-reported health weakening the association of physical functional decline and non-response. Respondents of this postal survey are fitter and healthier than non-respondents. This participation bias precludes the generalization of postal surveys results. © 2012 Elsevier Ireland Ltd.

Rovelli C.,Aix - Marseille University
Foundations of Physics | Year: 2016

Testable predictions of quantum mechanics are invariant under time reversal. But the evolution of the quantum state in time is not so, neither in the collapse nor in the no-collapse interpretations of the theory. This is a fact that challenges any realistic interpretation of the quantum state. On the other hand, this fact raises no difficulty if we interpret the quantum state as a mere calculation device, bookkeeping past real quantum events. © 2016 Springer Science+Business Media New York

Pranzetti D.,Aix - Marseille University
Classical and Quantum Gravity | Year: 2011

In this paper, I investigate the possible quantization, in the context of loop quantum gravity, of three-dimensional gravity in the case of positive cosmological constant and try to make contact with alternative quantization approaches already existing in the literature. Due to the appearance of an anomaly in the constraints algebra, previously studied as a first step of the analysis, alternative techniques developed for the quantization of systems with constraints algebras not associated with a structure Lie group need to be adopted. Therefore, I introduce an ansatz for a physical state, which gives some transition amplitudes in agreement with what one would expect from the TuraevViro model. Moreover, in order to check that this state implements the right dynamics, I show that it annihilates the master constraint for the theory up to the first order in Λ. © 2011 IOP Publishing Ltd.

Havaux M.,French Atomic Energy Commission | Havaux M.,French National Center for Scientific Research | Havaux M.,Aix - Marseille University
Plant Journal | Year: 2014

Carotenoids are known to play important roles in plants as antioxidants, accessory light-harvesting pigments, and attractants for pollinators and seed dispersers. A new function for carotenoids has recently emerged, which relates to the response of plants to environmental stresses. Reactive oxygen species, especially singlet oxygen, produced in the chloroplasts under stress conditions, can oxidize carotenoids leading to a variety of oxidized products, including aldehydes, ketones, endoperoxides and lactones. Some of those carotenoid derivatives, such as volatile β-cyclocitral, derived from the oxidation of β-carotene, are reactive electrophile species that are bioactive and can induce changes in gene expression leading to acclimation to stress conditions. This review summarizes the current knowledge on the non-enzymatic oxidation of carotenoids, the bioactivity of the resulting cleavage compounds and their functions as stress signals in plants. © 2013 The Author The Plant Journal © 2013 John Wiley & Sons Ltd.

Duval C.,Aix - Marseille University
Nuclear Physics B | Year: 2016

The Bargmann-Michel-Telegdi equations describing the motions of a spinning, charged, relativistic particle endowed with an anomalous magnetic moment in an electromagnetic field, are reconsidered. They are shown to duly stem from the linearization of the characteristic distribution of a presymplectic structure refining the original one of Souriau. In this model, once specialized to the case of a static electric-like field, the angular momentum and energy given by the associated moment map now correctly restore the spin-orbit coupling term. This is the state-of-the-art of unfinished joint work with Raymond Stora. © 2016 The Author.

Dumais J.,Harvard University | Forterre Y.,Aix - Marseille University
Annual Review of Fluid Mechanics | Year: 2011

Although they lack muscle, plants have evolved a remarkable range of mechanisms to create motion, from the slow growth of shoots to the rapid snapping of carnivorous plants and the explosive rupture of seed pods. Here we review the key fluid mechanics principles used by plants to achieve movements, summarizing current knowledge and recent discoveries. We begin with a brief overview of water transport and material properties in plants and emphasize that the poroelastic timescale of water diffusion through soft plant tissue imposes constraints on the possible mechanisms for motion. We then discuss movements that rely only on the transport of water, from irreversible growth to reversible swelling/shrinking due to osmotic or humidity gradients. We next show how plants use mechanical instabilitiessnap buckling, cavitation, and fractureto speed up their movements beyond the limits imposed by simple hydraulic mechanisms. Finally, we briefly discuss alternative schemes, involving capillarity or complex fluids.

Fenz S.F.,Leiden University | Sengupta K.,Aix - Marseille University
Integrative Biology (United Kingdom) | Year: 2012

Tremendous progress has been made in recent years in understanding the working of the living cell, including its micro-anatomy, signalling networks, and regulation of genes. However, an understanding of cellular phenomena using fundamental laws starting from first principles is still very far away. Part of the reason is that a cell is an active and exquisitely complex system where every part is linked to the other. Thus, it is difficult or even impossible to design experiments that selectively and exclusively probe a chosen aspect of the cell. Various kinds of idealised systems and cell models have been used to circumvent this problem. An important example is a giant unilamellar vesicle (GUV, also called giant liposome), which provides a cell-sized confined volume to study biochemical reactions as well as self-assembly processes that occur on the membrane. The GUV membrane can be designed suitably to present selected, correctly-oriented cell-membrane proteins, whose mobility is confined to two dimensions. Here, we present recent advances in GUV design and the use of GUVs as cell models that enable quantitative testing leading to insight into the working of real cells. We briefly recapitulate important classical concepts in membrane biophysics emphasising the advantages and limitations of GUVs. We then present results obtained over the last decades using GUVs, choosing the formation of membrane domains and cell adhesion as examples for in-depth treatment. Insight into cell adhesion obtained using micro-interferometry is treated in detail. We conclude by summarising the open questions and possible future directions. © 2012 The Royal Society of Chemistry.

Bertucci F.,French Institute of Health and Medical Research | Bertucci F.,Aix - Marseille University | Finetti P.,French Institute of Health and Medical Research | Birnbaum D.,French Institute of Health and Medical Research
Current Molecular Medicine | Year: 2012

During the last decade, gene expression profiling of breast cancer has revealed the existence of five molecular subtypes and allowed the establishment of a new classification. The basal subtype, which represents 15-25% of cases, is characterized by an expression profile similar to that of myoepithelial normal mammary cells. Basal tumors are frequently assimilated to triple-negative (TN) breast cancers. They display epidemiological and clinico-pathological features distinct from other subtypes. Their pattern of relapse is characterized by frequent and early relapses and visceral locations. Despite a relative sensitivity to chemotherapy, the prognosis is poor. Recent characterization of their molecular features, such as the dysfunction of the BRCA1 pathway or the frequent expression of EGFR, provides opportunities for optimizing the systemic treatment. Several clinical trials dedicated to basal or TN tumors are testing cytotoxic agents and/or molecularly targeted therapies. This review summarizes the current state of knowledge of this aggressive and hard-to-treat subtype of breast cancer. © 2012 Bentham Science Publishers.

Sahoo B.,National Institute of Technology Rourkela | Poncet S.,Aix - Marseille University
International Journal of Heat and Mass Transfer | Year: 2011

Non-Newtonian boundary layer flow and heat transfer over an exponentially stretching sheet with partial slip boundary condition has been studied in this paper. The flow is subject to a uniform transverse magnetic field. The heat transfer analysis has been carried out for two heating processes, namely (i) with prescribed surface temperature (PST), and (ii) prescribed heat flux (PHF). Suitable similarity transformations are used to reduce the resulting highly nonlinear partial differential equations into ordinary differential equations. An effective second order numerical scheme has been adopted to solve the obtained differential equations. The important finding in this communication is the combined effects of the partial slip and the third grade fluid parameters on the velocity, skin-friction coefficient and the temperature boundary layer. It is found that the third grade fluid parameter β increases the momentum boundary layer thickness and decreases the thermal boundary layer thickness. © 2011 Elsevier Ltd. All rights reserved.

Adam F.,University of Avignon | Abert-Vian M.,University of Avignon | Peltier G.,Aix - Marseille University | Chemat F.,University of Avignon
Bioresource Technology | Year: 2012

In order to comply with criteria of green chemistry concepts and sustainability, a new procedure has been performed for solvent-free ultrasound-assisted extraction (UAE) to extract lipids from fresh Nannochloropsis oculata biomass. Through response surface methodology (RSM) parameters affecting the oil recovery were optimized. Optimum conditions for oil extraction were estimated as follows: (i) 1000. W ultrasonic power, (ii) 30. min extraction time and (iii) biomass dry weight content at 5%. Yields were calculated by the total fatty acids methyl esters amounts analyzed by GC-FID-MS. The maximum oil recovery was around 0.21%. This value was compared with the one obtained with the conventional extraction method (Bligh and Dyer). Furthermore, effect of temperature on the yield was also investigated. The overall results show an innovative and effective extraction method adapted for microalgae oil recovery, without using solvent and with an enable scaling up. © 2012 Elsevier Ltd.

Erkosar B.,University Claude Bernard Lyon 1 | Storelli G.,University Claude Bernard Lyon 1 | Defaye A.,Aix - Marseille University | Leulier F.,University Claude Bernard Lyon 1
Cell Host and Microbe | Year: 2013

Given the complexity of the mammalian microbiota, there is a need for simple models to decipher the effector and regulatory mechanisms underlying host/microbiota mutualism. Approaches using Drosophila and its simple microbiota carry the potential to unravel the evolutionarily conserved mechanisms engaged in this association. Here, we review recent work carried out in this model, providing insights and exciting perspectives. © 2013 Elsevier Inc.

Mechanical stress in optical thin films can induce surface deflection of optical coatings. In the case of a substrate coated on both sides, a method is proposed which can provide perfect cancellation of this deflection, independently of the deposition process or any other external parameter, such as the temperature sensitivity of the mechanical stress. It is straightforward to implement this method, based on iso-admittance layers, since the thickness of such layers can be used to freely compensate for deflection effects only, without having any influence on the film's optical properties. This method is illustrated by two possible solutions for the design problem B from the Optical Interference Coatings (OIC) 2013 meeting. © 2014 Optical Society of America.

Lopez C.,Aix - Marseille University
Current Opinion in Neurology | Year: 2016

Purpose of review The review presents a selection of recent studies in the field of vestibular neuroscience, including how vestibular stimulation modulates space and body perception. Recent findings Recent neuroimaging studies identified the operculo-insular/retroinsular cortex as the core vestibular cortex and showed how it is reorganized after vestibular dysfunctions. Subliminal galvanic vestibular stimulation (GVS) induces long-term reduction of hemispatial neglect and improves vertical perception in stroke patients, but the underlying mechanisms remain to be identified. Healthy volunteer research suggests that GVS and caloric vestibular stimulation (CVS) modulate visual and somatosensory processing and that beneficial effects of GVS/CVS in stroke patients are not limited to merely rebalancing brain hemispheric activity. Another mechanism would be that GVS/CVS anchors the self to the body, thus promoting an egocentric frame of reference. Summary In addition to balancing the body, the vestibular cortical network contributes to modulate space, body and self-awareness. Emerging evidence suggests that the vestibular network expands into dimensions of emotion processing, mental health, and social cognition. Here, the importance of connecting vestibular physiology, affective neuroscience, and social neuroscience to better understand the psychological aspects of vertigo in otoneurology is discussed. © 2016 Wolters Kluwer Health, Inc. All rights reserved.

Harmelin J.-G.,Aix - Marseille University
Zootaxa | Year: 2014

The Levant Basin (SE Mediterranean) is the most exposed to the introduction of non-indigenous species. The current assessment of exotic bryozoans present along the coast of Lebanon has been completed by the recording of fourteen cheilostome species (one cryptogenic) collected by diving in 17 localities (2-42 m). This set of exotic bryozoans comprises ten genera, including four (Akatopora Davis, 1934, Drepanophora Harmer, 1957, Mucropetraliella Stach, 1936 and Predanophora Tilbrook, 2006) not previously reported in the Mediterranean, while Celleporaria is the most successful extra-Mediterranean genus with four species in the survey collection. A new Celleporina species, C. bitari n. sp., also collected in the Red Sea, is described. Although lessepsian migration through the Suez Canal is the main pathway for exotic bryozoans in this region, the geographic origin of some species suggests that shipping through Gibraltar Strait is also responsible to a large extent. Copyright © 2014 Magnolia Press.

Pellissier H.,Aix - Marseille University
Advanced Synthesis and Catalysis | Year: 2015

During the last ten years, an important number of novel highly efficient asymmetric conjugate additions of various nucleophiles to numerous acceptor-activated olefins have been developed on the basis of asymmetric nickel(II) catalysis by the very fact of the lower costs of nickel catalysts in comparison with other transition metals. These processes can be considered as one of the most powerful and reliable tools for the stereocontrolled formation of carbon-carbon bonds. Importantly, a range of fascinating nickel-catalyzed asymmetric domino reactions initiated by Michael additions has been successfully developed. The goal of this review is to collect the major developments in enantioselective nickel-catalyzed conjugate additions reported since the beginning of 2004, well illustrating the power of these inexpensive and highly abundant catalysts to achieve functionalized chiral compounds to be applied as key intermediates in the synthesis of biologically interesting molecules including natural products. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Wilson-Ewing E.,Aix - Marseille University
Classical and Quantum Gravity | Year: 2012

We study the scalar modes of linear perturbations in loop quantum cosmology. This is done on a lattice where each cell is taken to be homogeneous and isotropic and can be quantized via the standard homogeneous loop quantum cosmology techniques. The appropriate interactions between nearby cells are included in the Hamiltonian in order to obtain the correct physics. It is shown that the quantum theory is anomaly free: the scalar and diffeomorphism constraint operators weakly commute with the Hamiltonian. Finally, the effective theory encoding the leading order quantum gravity corrections is derived and is shown to give the same holonomy-corrected effective equations that have been obtained in previous studies. Communicated by P R L V Moniz. © 2012 IOP Publishing Ltd.

Dumur F.,Aix - Marseille University
Organic Electronics: physics, materials, applications | Year: 2015

The past decades have driven a great deal of interest for developing low-cost electroluminescent devices. In this aim, highly emissive phosphors based on Earth-abundant metals and presenting the advantage of environment-benignancy are actively researched. Based on these requirements, copper(I) complexes have been identified as favorable candidates that could advantageously replace the well-established iridium(III) complexes. © 2015 Elsevier B.V. All rights reserved.

Yan H.,Aix - Marseille University
Energy Policy | Year: 2015

Chinese policymakers have attached great importance to energy intensity reduction. However, the unprecedented urbanization process exercises additional pressure on the realization of energy intensity reduction targets. A better understanding of the impacts of urbanization is necessary for designing effective policies aimed at reaching the next energy intensity reduction targets. This paper empirically investigates the impacts of urbanization on China's aggregate and disaggregated energy intensities using a balanced panel dataset of 30 provinces covering the period from 2000 to 2012 and panel estimation techniques. The results show that urbanization significantly increases aggregate energy intensity, electricity intensity and coal intensity. © 2015 Elsevier Ltd.

Guenneau S.,Aix - Marseille University | Puvirajesinghe T.M.,French Institute of Health and Medical Research
Journal of the Royal Society Interface | Year: 2013

Here, we adapt the concept of transformational thermodynamics, whereby the flux of temperature is controlled via anisotropic heterogeneous diffusivity, for the diffusion and transport of mass concentration. The n-dimensional, time-dependent, anisotropic heterogeneous Fick's equation is considered, which is a parabolic partial differential equation also applicable to heat diffusion, when convection occurs, for example, in fluids. This theory is illustrated with finite-element computations for a liposome particle surrounded by a cylindrical multi-layered cloak in a water-based environment, and for a spherical multi-layered cloak consisting of layers of fluid with an isotropic homogeneous diffusivity, deduced from an effective medium approach. Initial potential applications could be sought in bioengineering. © 2013 The Author(s) Published by the Royal Society. All rights reserved.

Signoli M.,Aix - Marseille University
Clinical Microbiology and Infection | Year: 2012

Drawing its etymology from the Latin pestis (curse), plague, over the centuries, has been more dreaded by humankind than any other epidemic. The Apocalypse had recognized plague as the archetypal divine curse, 'the power to kill over a fourth of the earth'. Plague is thus a particular topic of study, insofar that it is one of the rare epidemics that has had recurrent major consequences on demography and human societies. Its highly transmissible nature, the brutality of its action, its high pathogenicity, marked by strong lethality and great swiftness, and the complete absence of treatment options before the 20th century conferred on it a sinister aspect. Generating a series of severe demographic crises, well known in the Western world, it has necessarily influenced the evolution of societies at both the biological and cultural levels. © 2012 The Author. Clinical Microbiology and Infection © 2012 European Society of Clinical Microbiology and Infectious Diseases.

Brutin D.,Aix - Marseille University
Colloids and Surfaces A: Physicochemical and Engineering Aspects | Year: 2013

We report the pattern formation of nano-particles of iso-density water-based nanofluid drops. During the spontaneous evaporation of a droplet in air under atmospheric conditions, the solvent evaporates and nano-particles are deposited onto the substrate. Depending on the concentration, two different patterns are observed: an o-ring pattern and a continuous nano-particle flower pattern. We observe a critical concentration that corresponds to the transition between the two patterns. Humidity is controlled and modified to investigate its effect on the evaporation dynamics and on pattern formation. Surprisingly, the leading pattern is identical regardless of the evaporation time, and the evaporative mass fluxes measured are slightly higher than the expected flux, following a classical purely diffusive model for pure fluids. Two explanations are proposed: the first is that the diffusion coefficient of the nanofluid in humid air is different from that of pure water in dry air. The second is based on the experimental observation of an increase in the spreading of the nanofluid, leading to an increase in the drop perimeter, a decrease in the contact angle and thus an improvement in the evaporation rate. © 2013 Elsevier B.V.

Larose E.,French National Center for Scientific Research | Planes T.,French National Center for Scientific Research | Rossetto V.,French National Center for Scientific Research | Margerin L.,Aix - Marseille University
Applied Physics Letters | Year: 2010

This article presents an imaging technique to locate a weak perturbation in a multiple scattering environment. We derive a formula to predict the spatiotemporal decorrelation of diffuse coda waves induced by an extra scatterer. Locating this new defect is formulated as an inverse problem which is solved by a maximum likelihood approach. Using elastic waves in the 50-400 kHz frequency band, we recover the position of a millimetric hole drilled in a concrete sample with a precision of a few centimeter. Note that the size of the defect is comparable to the size of the myriads of heterogeneities constituting the sample. © 2010 American Institute of Physics.

Guilliams M.,Inflammation Research Center | Guilliams M.,Ghent University | Malissen B.,Aix - Marseille University
Immunity | Year: 2016

In response to the comments by Lutz and colleagues to our recent preview of the paper from Helft and colleagues (Helft et al., 2015), we wish to respectfully point out that granulocyte-macrophage colony-stimulating factor (GM-CSF) bone-marrow (BM) cultures have indeed allowed conceptual advances essential for our current understanding of the immunobiology of myeloid cells. However, the study by Helft et al. emphasized that even by focusing on CD11c+MHC II+ cells, this model yields a mixed bag of myeloid cells that derive from both common dendritic cell (DC) precursors and common monocyte precursors and showed gene-expression profiles distantly mimicking those expressed by their in vivo counterparts. Given the complexity of the cells generated in GM-CSF BM cultures, we suggested that recently described Flt3L-based culture systems are better suited for the study of conventional DCs (cDCs) in vitro and the manufacture of cDC-based vaccines. In response to the comments by Lutz and colleagues to our recent preview of the paper from Helft and colleagues (Helft et al., 2015), we wish to respectfully point out that granulocyte-macrophage colony-stimulating factor (GM-CSF) bone-marrow (BM) cultures have indeed allowed conceptual advances essential for our current understanding of the immunobiology of myeloid cells. However, the study by Helft et al. emphasized that even by focusing on CD11c+MHC II+ cells, this model yields a mixed bag of myeloid cells that derive from both common dendritic cell (DC) precursors and common monocyte precursors and showed gene-expression profiles distantly mimicking those expressed by their in vivo counterparts. Given the complexity of the cells generated in GM-CSF BM cultures, we suggested that recently described Flt3L-based culture systems are better suited for the study of conventional DCs (cDCs) in vitro and the manufacture of cDC-based vaccines. © 2016 Elsevier Inc.

Ormeno E.,Aix - Marseille University | Goldstein A.,University of California at Berkeley | Niinemets T.,Estonian University of Life Sciences
TrAC - Trends in Analytical Chemistry | Year: 2011

Biogenic volatile organic compounds (BVOCs), released by practically all plants, have important atmospheric and ecological consequences. Because BVOC-emission measurements are especially tedious, complex and extremely variable between species, two approaches have been used in scientific studies to try to estimate BVOC-emission types and rates from plant species. The first, which has known little success, involves grouping species according to plant-taxonomy criteria (typically, genus and family). The second involves studying the correlation between BVOC content and emission (i.e. how leaf content could be used to estimate emissions). The latter strategy has provided controversial results, partly because BVOCs are amazingly chemically diverse, and, as a result, techniques used to study plant BVOC content, which we review, cannot be equally adequate for all analytes.In order to choose an adequate technique, two patterns must be distinguished. Specifically stored compounds - mainly monoterpenes and sesquiterpenes that dominate the essential oil obtained from a plant - are permanently and massively present in specific storage structures (e.g., secretory cavities, trichomes) of the order of μg/g-mg/g and usually allow emissions to occur during stress periods when terpenes are weakly synthesized. These BVOCs can be studied directly through traditional extraction techniques (e.g., hydrodistillation) and novel techniques (e.g., application of microwaves and ultrasound), and indirectly by trapping techniques involving the collection, within adsorbent material, of BVOCs present in the headspace of a plant.Non-specifically stored compounds (e.g., isoprene, 2-methyl-3-buten-2-ol, and, in species without storage structures, monoterpenes and sesquiterpenes) can only be temporarily accumulated in leaf aqueous and lipid phases in small concentrations of the order of ng/g. As a result, studying their concentration in leaves requires the use of trapping techniques, more sensitive to trace amounts. Unlike for specifically stored BVOCs, knowledge of the concentration of non-specifically stored BVOCs cannot provide any information regarding the emission potential of a species but, instead, provides crucial information to understand why BVOC emissions may be uncoupled from the physiological processes that drive their synthesis.We describe both extracting and trapping techniques and discuss them in terms of the technical choices that may cause losses of thermolabile constituents, chemical transformations, different volatile recoveries and suitability to represent plant content of BVOCs faithfully. The second part of this review addresses technical shortcomings and biological and environmental factors that may alter the correlations between BVOC content and emission from plants. © 2011 Elsevier Ltd.

Nieoullon A.,Aix - Marseille University
Journal of Applied Biomedicine | Year: 2011

Pathophysiological processes of neurodegenerative diseases share in common for most of them aggregation of related proteins, which represents halt marks of the degenerative processes. Recent advances in the knowledge of these proteinopathies show that the same protein could contribute to various diseases thus suggesting common pathological process. In such a way the specificity of the brain neuronal system targeted by the protein dysfunction could be the way of differential clinical expression rather than different pathological processes. This very stimulating view of the neurodegenerative diseases based on physiopathology led us to suggest possible degenerative mechanisms shared by different diseases although the causes of the disease itself still remains unclear. In this respect since genetic forms of the degenerative diseases are rather rare, exploring the involvement of genes is a current way to enter into the disease degenerative process. It is thus speculated that idiopathic forms of the diseases are related to close interactions between genetic and environmental factors, the genetic component being able to favor - or on the contrary to protect against - the disease process. Because of the current view that basic mechanism of cell death in degenerative diseases is related to a rather limited number of processes in which oxidative stress could play a central role resulting in protein dysfunction and aggregation, one can speculate that putative neuroprotective medicines could be soon proposed based on active limitation of protein accumulation in the brain. © Journal of Applied Biomedicine.

Roux P.,Joseph Fourier University | Wathelet M.,Joseph Fourier University | Roueff A.,Aix - Marseille University
Geophysical Research Letters | Year: 2011

We present here surface-wave tomography results for the San Andreas Fault in the Parkfield area, California, USA, that were extracted from microseismic noise in the 0.15 Hz to 0.35 Hz frequency band using passive seismic-correlation techniques. Using directive noise incoming from the Pacific Ocean, passive seismic-noise tomography was performed using three-component sensors from a dense seismic network. A rotation algorithm was applied to the nine-component noise-correlation tensor that optimally forced each station pair to re-align in the noise direction, a necessary condition to extract unbiased travel-times from passive seismic processing. After the rotation was performed, an optimal surface-wave tensor is obtained from which Love waves were extracted for tomography inversion. Dispersion curves were then inverted to obtain a three-dimensional shear-velocity map showing vertical geological structures and a 1.3-km wide low seismic velocity dip, which are in agreement with previous tomography studies in the same area. Copyright 2011 by the American Geophysical Union.

Guiot J.,Aix - Marseille University | de Vernal A.,University of Quebec at Montreal
Quaternary Science Reviews | Year: 2011

We address the issue of spatial autocorrelation, an occurrence that may introduce biases in the evaluation of the performance of transfer functions, by using two fundamentally different approaches, one based on calibration (weighted averaging partial least squares regressions; WA-PLS) and the other based on similarities (modern analogue technique; MAT). The tests were made after spatial standardization of 700 North Atlantic surface data points, which include 29 dinocyst taxa and 4 climate parameters. The evaluation of transfer function performance was made by defining a verification dataset that was gradually isolated from the calibration or comparison datasets. Although strong spatial autocorrelation characterizes the original climate parameter distribution, the results show that the spatial structure of data has relatively low effect on the calculation of the error of prediction. They also show that the performances of MAT are generally better than those of WA-PLS, with lower error of prediction. The better performance of MAT in the present study can be explained by the non-modal distribution of salinity and temperature in the studied marine environments, which is not appropriate for the application of WA-PLS. The two methods yield equivalent results about the spatial structure of the residuals based on empirical semi-variograms. The analyses we performed include the comparison of reconstructions based on original raw data and gridded data. Results suggest that the gridding of the reference database may reduce the noise and thus improve the performance of the techniques. © 2011 Elsevier Ltd.

The development of hand preferences for object-directed actions and pointing gestures was investigated in toddlers sampled bimonthly between 15 and 25 months of age. Language level was also assessed, in an attempt to examine the relationship between handedness and language development. Results did not reveal any changes over the study period in the mean Handedness Index of the whole sample, both for bimanual manipulative activities and pointing gestures. However, the categorization of participants as left-handers, right-handers, or non-lateralized revealed that most of children presented nonlinear individual trajectories in the development of hand preference. Moreover, the only significant correlations observed between hand preferences for manipulation and pointing were negative correlations between the strength of hand preferences at 19 and 21 months of age, suggesting that manipulative actions and communicative gestures are controlled by different networks in the left cerebral hemisphere. These findings are discussed in relation to the development of speech-gesture links in infancy. © 2011 Wiley Periodicals, Inc.

Clinical trials increasingly occur on a global scale as industry and government sponsors in wealthy countries move trials to low- and middle-income countries. The globalization of clinical research raises important questions about the economical and ethical aspects of clinical research and the translation of trial results to clinical practice: which ethical standards are applied? Are trials results accurate and valid, and can they be extrapolated to other settings? This article provides an overview of the strategy approved by the European Medicines Agency (EMA) to clarify ethical standards for clinical research conducted outside the European Economic Area (EEA) and included in Marketing Authorization Applications. Reference to the EMA Reflection paper is made. © 2011 Martinus Nijhoff Publishers.

Pierre Th.,Aix - Marseille University
Review of Scientific Instruments | Year: 2013

In a new toroidal laboratory plasma device including a poloidal magnetic field created by an internal circular conductor, the confinement efficiency of the magnetized plasma and the turbulence level are studied in different situations. The plasma density is greatly enhanced when a sufficiently large poloidal magnetic field is established. Moreover, the instabilities and the turbulence usually found in toroidal devices without sheared magnetic field lines are suppressed by the finite rotational transform. The particle confinement time is estimated from the measurement of the plasma decay time. It is compared to the Bohm diffusion time and to the value predicted by different diffusion models, in particular neoclassical diffusion involving trapped particles. © 2013 American Institute of Physics.

Descotes-Genon S.,University Paris - Sud | Knecht M.,Aix - Marseille University
European Physical Journal C | Year: 2012

Dispersive representations of the ππ scattering amplitudes and pion form factors, valid at two-loop accuracy in the low-energy expansion, are constructed in the presence of isospin-breaking effects induced by the difference between the charged and neutral pion masses. Analytical expressions for the corresponding phases of the scalar and vector pion form factors are computed. It is shown that each of these phases consists of the sum of a "universal" part and a form-factor dependent contribution. The first one is entirely determined in terms of the ππ scattering amplitudes alone, and reduces to the phase satisfying Watson's theorem in the isospin limit. The second one can be sizeable, although it vanishes in the same limit. The dependence of these isospin corrections with respect to the parameters of the subthreshold expansion of the ππ amplitude is studied, and an equivalent representation in terms of the S-wave scattering lengths is also briefly presented and discussed. In addition, partially analytical expressions for the two-loop form factors and ππ scattering amplitudes in the presence of isospin breaking are provided. © 2012 Springer-Verlag / Società Italiana di Fisica.

Varela G.,University of Salamanca | Thomas P.A.,Aix - Marseille University
Journal of Thoracic Disease | Year: 2014

More than 75% of the cases of non-small cell lung cancer (NSCLC) are diagnosed in advanced stages (IIIA-IV). Although in these patients the role of surgery is unclear, complete tumor resection can be achieved in selected cases, with good long-term survival. In this review, current indications for surgery in advanced NSCLC are discussed. In stage IIIA (N2), surgery after induction chemotherapy seems to be the best option. The indication of induction chemotherapy plus radiotherapy is debatable due to potential postoperative complications but recently reported experiences have not shown a higher postoperative risk in patients after chemo and radiotherapy induction even if pneumonectomy is performed. In cases of unexpected N2 found during thoracotomy, lobectomy plus systematic nodal dissection is recommended mostly for patients with single station disease. In stage IIIB, surgery is only the choice for resectable T4N0-1 cases and should not be indicated in cases of N2 disease. Favorable outcomes are reported after extended resections to the spine and mediastinal structures. Thorough and individualized discussion of each stage IIIB case is encouraged in the context of a multidisciplinary team. For stage IV oligometastatic cases, surgery can still be included when planning multimodality treatment. Brain and adrenal gland are the two most common sites of oligometastases considered for local ablative therapy. © Pioneer Bioscience Publishing Company.

Longhi S.,Aix - Marseille University
FEBS Letters | Year: 2015

In this review I summarize available data pointing to the abundance of structural disorder within the nucleoprotein (N) from three paramyxoviruses, namely the measles (MeV), Nipah (NiV) and Hendra (HeV) viruses. I provide a detailed description of the molecular mechanisms that govern the disorder-to-order transition that the intrinsically disordered C-terminal domain (NTAIL) of their N proteins undergoes upon binding to the C-terminal X domain (XD) of the homologous phosphoproteins. I also show that a significant flexibility persists within NTAIL-XD complexes, which makes them illustrative examples of "fuzziness". Finally, I discuss the functional implications of structural disorder for viral transcription and replication in light of the promiscuity of disordered regions and of the considerable reach they confer to the components of the replicative machinery. © 2015 Federation of European Biochemical Societies.Published by Elsevier B.V. All rights reserved.

Cabasino M.P.,University of Cagliari | Giua A.,Aix - Marseille University | Seatzu C.,University of Cagliari
IEEE Transactions on Automation Science and Engineering | Year: 2014

In this paper, we focus on labeled Petri nets with silent transitions that may either correspond to fault events or to regular unobservable events. We address the problem of deriving a procedure to determine if a given net system is diagnosable, i.e., the occurrence of a fault event may be detected for sure after a finite observation. The proposed procedure is based on our previous results on the diagnosis of discrete-event systems modeled with labeled Petri nets, whose key notions are those of basis markings and minimal explanations, and is inspired by the diagnosability approach for finite state automata proposed by Sampath in 1995. In particular, we first give necessary and sufficient conditions for diagnosability. Then, we present a method to test diagnosability that is based on the analysis of two graphs that depend on the structure of the net, including the faults model, and the initial marking. © 2013 IEEE.

Charousset C.,Institute Osteo Articulaire Paris Courcelles | Zaoui A.,University Paris Diderot | Bellaiche L.,Center dImage Medicale Bachaumont | Piterman M.,Aix - Marseille University
Arthroscopy - Journal of Arthroscopic and Related Surgery | Year: 2014

Purpose To evaluate the clinical and magnetic resonance imaging (MRI) outcome of arthroscopic rotator cuff repair with the use of leukocyte-platelet- rich plasma (L-PRP) in patients with large or massive rotator cuff tears. Methods A comparative cohort of patients with large or massive rotator cuff tears undergoing arthroscopic repair was studied. Two consecutive groups of patients were included: rotator cuff repairs with L-PRP injection (group 1, n = 35) and rotator cuff repairs without L-PRP injection (group 2, n = 35). A double-row cross-suture cuff repair was performed by a single surgeon with the same rehabilitation protocol. Patients were clinically evaluated with the Constant score; Simple Shoulder Test score; University of California, Los Angeles (UCLA) score; and strength measurements by use of a handheld dynamometer. Rotator cuff healing was evaluated by postoperative MRI using the Sugaya classification (type 1 to type 5). Results We prospectively evaluated the 2 groups at a minimum 2-year follow-up. The results did not show differences in cuff healing between the 2 groups (P =.16). The size of recurrent tears (type 4 v type 5), however, was significantly smaller in group 1 (P =.008). There was no statistically significant difference in the recurrent tear rate (types 4 and 5) between the 2 groups (P =.65). There was no significant difference between group 1 and group 2 in terms of University of California, Los Angeles score (29.1 and 30.3, respectively; P =.90); Simple Shoulder Test score (9.9 and 10.2, respectively; P =.94); Constant score (77.3 and 78.1, respectively; P =.82); and strength (7.5 and 7.0, respectively; P =.51). Conclusions In our study the use of autologous L-PRP did not improve the quality of tendon healing in patients undergoing arthroscopic repair of large or massive rotator cuff tears based on postoperative MRI evaluation. The only significant advantage was that the L-PRP patients had smaller iterative tears. However, the functional outcome was similar in the 2 groups of patients. Level of Evidence Level III, case-control study. © 2014 The Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Kuhnt W.,University of Kiel | Holbourn A.,University of Kiel | Moullade M.,Aix - Marseille University
Geology | Year: 2011

The onset of the early Aptian oceanic anoxic event (OAE) 1a (ca. 120 Ma) coincided with a major perturbation of the carbon cycle, which is reflected in the sedimentary carbon isotope record. Triggering mechanisms, duration, and climatic repercussions of this episode of accelerated organic matter burial remain poorly constrained. Here, we present millennialscale bulk rock carbon and oxygen isotope data from a marly subtropical intrashelf basin (La Bédoule, southeast France) with unusually high sedimentation rates, which track the onset of OAE1a in unprecedented resolution. Our record reveals that the negative, low-amplitude δ13C excursion preceding OAE1a lasted >100 k.y., implying that enhanced volcanic CO2 emission and/or pulsed methane dissociation over a prolonged time span were instrumental in triggering OAE1a. The main positive carbon isotope shift at the onset of OAE1a, previously regarded as continuous, occurred stepwise over an extended period of >300 k.y. Transient climate cooling during the initial δ13C increase probably reflects ephemeral high-latitude glaciation, triggered by changes in radiative forcing and drawdown of atmospheric CO2. © 2011 Geological Society of America.

Peltier G.,Aix - Marseille University | Aro E.-M.,University of Turku | Shikanai T.,Kyoto University
Annual Review of Plant Biology | Year: 2016

Oxygenic photosynthesis converts solar energy into chemical energy in the chloroplasts of plants and microalgae as well as in prokaryotic cyanobacteria using a complex machinery composed of two photosystems and both membrane-bound and soluble electron carriers. In addition to the major photosynthetic complexes photosystem II (PSII), cytochrome b6f, and photosystem I (PSI), chloroplasts also contain minor components, including a well-conserved type I NADH dehydrogenase (NDH-1) complex that functions in close relationship with photosynthesis and likewise originated from the endosymbiotic cyanobacterial ancestor. Some plants and many microalgal species have lost plastidial ndh genes and a functional NDH-1 complex during evolution, and studies have suggested that a plastidial type II NADH dehydrogenase (NDH-2) complex substitutes for the electron transport activity of NDH-1. However, although NDH-1 was initially thought to use NAD(P)H as an electron donor, recent research has demonstrated that both chloroplast and cyanobacterial NDH-1s oxidize reduced ferredoxin. We discuss more recent findings related to the biochemical composition and activity of NDH-1 and NDH-2 in relation to the physiology and regulation of photosynthesis, particularly focusing on their roles in cyclic electron flow around PSI, chlororespiration, and acclimation to changing environments. Copyright © 2016 by Annual Reviews. All rights reserved.

Knecht M.,Aix - Marseille University
Nuclear and Particle Physics Proceedings | Year: 2015

The calculations entering the prediction of the standard model value for the anomalous magnetic moment of the muon aμ are reviewed, and compared to the very accurate experimental measurement. The situation for the electron is discussed in parallel. © 2015 Elsevier B.V.

Kuusi T.,Aalto University | Mingione G.,University of Parma | Sire Y.,Aix - Marseille University
Communications in Mathematical Physics | Year: 2015

We develop an existence, regularity and potential theory for nonlinear integrodifferential equations involving measure data. The nonlocal elliptic operators considered are possibly degenerate and cover the case of the fractional p-Laplacean operator with measurable coefficients. We introduce a natural function class where we solve the Dirichlet problem, and prove basic and optimal nonlinear Wolff potential estimates for solutions. These are the exact analogs of the results valid in the case of local quasilinear degenerate equations established by Boccardo and Gallouët (J Funct Anal 87:149–169, 1989, Partial Differ Equ 17:641–655, 1992) and Kilpeläinen and Malý (Ann Scuola Norm Sup Pisa Cl Sci (IV) 19:591–613, 1992, Acta Math 172:137–161, 1994). As a consequence, we establish a number of results that can be considered as basic building blocks for a nonlocal, nonlinear potential theory: fine properties of solutions, Calderón–Zygmund estimates, continuity and boundedness criteria are established via Wolff potentials. A main tool is the introduction of a global excess functional that allows us to prove a nonlocal analog of the classical theory due to Campanato (Ann Mat Pura Appl (IV) 69:321–381, 1965). Our results cover the case of linear nonlocal equations with measurable coefficients, and the one of the fractional Laplacean, and are new already in such cases. © 2015, Springer-Verlag Berlin Heidelberg.

Gillet D.,Aix - Marseille University | Fokin A.B.,Russian Academy of Sciences
Astronomy and Astrophysics | Year: 2014

Context. Emission lines observed in radially pulsating stars are thought to be produced by atoms de-exciting after being excited by a shock wave that is traveling into and then compressing, heating, and accelerating the atmospheric gas. Aims. With the help of recent observations, we examine the origin of all the different types of emission lines of hydrogen and helium that appear during a pulsation cycle. Methods. To analyze the physical origin of emission lines, we used the different models of atmospheric dynamics of RR Lyrae stars that have been calculated so far. Results. In contrast to a recent explanation, we propose that the redshifted emission component of Hα, which occurs near the pulsation phase 0.3, is produced by the main shock. In this case, the emission is the natural consequence of the large extension of the expanding atmosphere. Therefore, this (weak) emission should only be observed in RR Lyrae stars for which the main shock will propagate far enough from the photosphere. It appears as a P-Cygni type profile. We estimate the shock front velocity during the shock propagation in the atmosphere and show that it decreases by 40% when the Hα emitting-shock passes from the photospheric level to the upper atmosphere. The Hα P-Cygni profile observed in long-period Cepheids also seems to be caused by the main shock wave. Although to date He II has only been detected in some Blazhko stars, a comprehensive survey of RR Lyrae stars is necessary to confirm this trend, so we can say that the most intense shocks will only be observed in Blazhko stars. Conclusions. The development of a model of atmospheric pulsation that takes the effects of 2D and 3D convection into account, seems to be a necessary step to fully quantify the effects of shock waves on the atmospheric dynamics of radially pulsating stars. © ESO, 2014.

Gomot M.,University of Tours | Wicker B.,Aix - Marseille University
International Journal of Psychophysiology | Year: 2012

Autism is a pervasive neurodevelopmental disorder characterized by impairment of communication and social interaction, as well as by high levels of repetitive and ritualistic behaviours. This last dimension results in major difficulties in daily life: clinical reports of individuals with Autism Spectrum Disorder (ASD) show that they present tantrums as a response to change, or restricted interests and repetitive behaviours in order to prevent or minimize change. Such a crucial need to maintain sameness suggests substantial differences in how the ASD brain predicts the environment, and this might have a fundamental role in the deficit revealed in the highly unpredictable social world. Several lines of evidence indicating difficulties in generating or using predictions in ASD due to atypical information processing will be presented in this review. For instance, several studies have revealed that people with ASD demonstrate a unique profile of cognitive abilities, with strategies that depend to an abnormally large extent on sensory systems, at the expense of more integrative processing requiring an awareness of contextual subtleties necessary for prediction. At a more elementary level, patients with autism manifest unusual processing of unpredictable events, which might be rooted in a basic difference in how the brain orients to changing, novel sensory stimuli. This review presents results from ERPs and fMRI studies illustrating the psychophysiological mechanisms and neural bases underlying such phenomena in ASD. We propose that such dysfunction in the ability to build flexible prediction in ASD may originate from impaired top-down influence over a variety of sensory and higher level information processing, a physiopathological hypothesis which dovetails with the cortical under connectivity current theory. © 2011 Elsevier B.V.

Immersed boundary methods for computing confined fluid and plasma flows in complex geometries are reviewed. The mathematical principle of the volume penalization technique is described and simple examples for imposing Dirichlet and Neumann boundary conditions in one dimension are given. Applications for fluid and plasma turbulence in two and three space dimensions illustrate the applicability and the efficiency of the method in computing flows in complex geometries, for example in toroidal geometries with asymmetric poloidal cross-sections. © © Cambridge University Press 2015.

Riello A.,Aix - Marseille University | Riello A.,University of Toulon
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

We calculate the most divergent contribution to the nondegenerate sector of the self-energy (or "melonic") graph in the context of the Lorentzian Engle-Pereira-Rovelli-Livine and Freidel-Krasnov spin foam model of quantum gravity. We find that such a contribution is logarithmically divergent in the cutoff over the SU(2) representation spins when one chooses the face amplitude guaranteeing the face-splitting invariance of the foam. We also find that the dependence on the boundary data is different from that of the bare propagator. This fact has its origin in the noncommutativity of the Engle-Pereira-Rovelli- Livine and Freidel-Krasnov Yγ map with the projector onto SL(2,C)-invariant states. In the course of the paper, we discuss in detail the approximations used during the calculations, their geometrical interpretation, and the physical consequences of our result. © 2013 American Physical Society.

Escarguel A.,Aix - Marseille University
European Physical Journal D | Year: 2010

An argon magnetized plasma column is created with primary energetic electrons in the Mistral device. Low frequency instabilities regularly rotating around this column are observed with an ultra-fast camera and a spectroscopic device. Experimental results coupled to a coronal code show the presence of a few percents of fast (hot) electrons inside the ejected plasma. It also shows that ultra-fast camera analysis of the ejected plasma can only give information on the primary electron population. Finally, these results suggest that the radial decrease of the light emitted by the ejected plasma is essentially due to the radial decrease of the mean energy of the hot electrons. © 2009 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.

Robaglia C.,Aix - Marseille University | Thomas M.,University Paris - Sud | Meyer C.,French National Institute for Agricultural Research
Current Opinion in Plant Biology | Year: 2012

The perception of nutrient and energy levels inside and outside the cell is crucial to adjust growth and metabolism to available resources. The signaling pathways centered on the conserved TOR and SnRK1/Snf1/AMPK kinases have crucial and numerous roles in nutrient and energy sensing and in translating this information into metabolic and developmental adaptations. In plants evidence is mounting that, like in other eukaryotes, these signaling pathways have pivotal and antagonistic roles in connecting external or intracellular cues to many biological processes, including ribosome biogenesis, regulation of translation, cell division, accumulation of reserves and autophagy. Data on the plant TOR pathway have been hitherto rather scarce but recent findings have shed new light on its roles in plants. Moreover, the distinctive energy metabolism of photosynthetic organisms may reveal new features of these ancestral eukaryotic signaling elements. © 2012 Elsevier Ltd.

Rovelli C.,Aix - Marseille University | Rovelli C.,University of Toulon
Classical and Quantum Gravity | Year: 2015

Disavowed by one of its fathers, ill-defined, never empirically tested, the Wheeler-DeWitt equation has nevertheless had a powerful influence on fundamental physics. A well-deserved one. © 2015 IOP Publishing Ltd.

Bourrely C.,Aix - Marseille University | Soffer J.,Temple University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2015

The quantum statistical parton distributions approach proposed more than one decade ago is revisited by considering a larger set of recent and accurate Deep Inelastic Scattering (DIS) experimental results. It enables us to improve the description of the data by means of a new determination of the parton distributions. We will see that a large gluon polarization emerges, giving a significant contribution to the proton spin. © 2014 The Authors.

Bourrely C.,Aix - Marseille University | Soffer J.,Temple University
Nuclear Physics A | Year: 2015

The quantum statistical parton distributions approach proposed more than one decade ago is revisited by considering a larger set of recent and accurate Deep Inelastic Scattering experimental results. It enables us to improve the description of the data by means of a new determination of the parton distributions. This global next-to-leading order QCD analysis leads to a good description of several structure functions, involving unpolarized parton distributions and helicity distributions, in a broad range of x and Q2 and in terms of a rather small number of free parameters. There are several challenging issues and in particular the confirmation of a large positive gluon helicity distribution. The predictions of this theoretical approach will be tested for single-jet production and charge asymmetry in W± production in p-p and pp collisions up to LHC energies, using recent data and also for forthcoming experimental results. © 2015 Elsevier B.V.

Zeitoun D.E.,Aix - Marseille University
Physics of Fluids | Year: 2015

From previous works on the shock Mach number attenuation along small size diameter tubes, two different power-law correlations in laminar and turbulent flows in shock tube are proposed in this paper for describing this attenuation and the shock wave behavior. These correlations are based on a local scaling ratio built from driven gas conditions, hydraulic diameter tube, and shock wave propagation distance. A comparison to numerical and experimental existing data is presented and discussed. © 2015 AIP Publishing LLC.

Daudet L.,Aix - Marseille University
IEEE Signal Processing Magazine | Year: 2010

Greedy methods are often the only practical way of solving very large sparse approximation problems. Among such methods, Matching Pursuit (MP) is undoubtedly one of the most widely used, due to its simplicity and relatively low overhead. Since MP works sequentially, however, it is not straightforward to formulate it as a parallel algorithm, to take advantage of multi-core platforms for real-time processing. In this paper, we investigate how a slight modification of MP makes it possible to break down the decomposition into multiple local tasks, while avoiding blocking effects. Our simulations on audio signals indicate that this Parallel Local Matching Pursuit (PLoMP) gives results comparable to the original MP algorithm, but could potentially run in a fraction of the time on-the-fly sparse approximations of high-dimensional signals should soon become a reality. © 2006 IEEE.

Chandre C.,Aix - Marseille University
Annals of Physics | Year: 2015

First-class constraints constitute a potential obstacle to the computation of a Poisson bracket in Dirac's theory of constrained Hamiltonian systems. Using the pseudoinverse instead of the inverse of the matrix defined by the Poisson brackets between the constraints, we show that a Dirac-Poisson bracket can be constructed, even if it corresponds to an incomplete reduction of the original Hamiltonian system. The uniqueness of Dirac brackets is discussed. The relevance of this procedure for infinite dimensional Hamiltonian systems is exemplified. © 2015 Elsevier Inc.

Barrau A.,CNRS Laboratory of Subatomic Physics & Cosmology | Rovelli C.,Aix - Marseille University | Rovelli C.,University of Toulon
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014

It is possible that black holes hide a core of Planckian density, sustained by quantum-gravitational pressure. As a black hole evaporates, the core remembers the initial mass and the final explosion occurs at macroscopic scale. We investigate possible phenomenological consequences of this idea. Under several rough assumptions, we estimate that up to several short gamma-ray bursts per day, around 10 MeV, with isotropic distribution, can be expected coming from a region of a few hundred light years around us. © 2014 The Authors.

Kravets V.G.,University of Manchester | Schedin F.,University of Manchester | Jalil R.,University of Manchester | Britnell L.,University of Manchester | And 7 more authors.
Nature Materials | Year: 2013

The non-trivial behaviour of phase is crucial for many important physical phenomena, such as, for example, the Aharonov-Bohm effect and the Berry phase. By manipulating the phase of light one can create 'twisted' photons, vortex knots and dislocations which has led to the emergence of the field of singular optics relying on abrupt phase changes. Here we demonstrate the feasibility of singular visible-light nano-optics which exploits the benefits of both plasmonic field enhancement and the peculiarities of the phase of light. We show that properly designed plasmonic metamaterials exhibit topologically protected zero reflection yielding to sharp phase changes nearby, which can be employed to radically improve the sensitivity of detectors based on plasmon resonances. By using reversible hydrogenation of graphene and binding of streptavidin-biotin, we demonstrate an areal mass sensitivity at a level of fg mm -2 and detection of individual biomolecules, respectively. Our proof-of-concept results offer a route towards simple and scalable single-molecule label-free biosensing technologies. © 2013 Macmillan Publishers Limited. All rights reserved.

Rovelli C.,Aix - Marseille University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

Understanding thermodynamics and statistical mechanics in the fully general relativistic context is an open problem. I give tentative definitions of equilibrium state, mean values, mean geometry, entropy and temperature, which reduce to the conventional ones in the nonrelativistic limit but remain valid for a general covariant theory. The formalism extends to quantum theory. The construction builds on the idea of thermal time, on a notion of locality for this time, and on the distinction between global and local temperature. The last is the temperature measured by a local thermometer and is given by kT=hdτ/ds, with k the Boltzmann constant, h the Planck constant, ds proper time and dτ the equilibrium thermal time. © 2013 American Physical Society.

Shrira V.I.,Keele University | Forget P.,Aix - Marseille University
Journal of Physical Oceanography | Year: 2015

Inertial band response of the upper ocean to changing wind is studied both theoretically and by analysis of observations in the northwestern Mediterranean. On the nontraditional f plane, because of the horizontal component of the earth's rotation for waves of inertial band with frequencies slightly below the local inertial frequency f, there is a waveguide in the mixed layer confined from below by the pycnocline. It is argued that when the stratification is shallow these waves are most easily and strongly excited by varying winds as nearinertial oscillations (NIOs). These motions have been overlooked in previous studies because they are absent under the traditional approximation. The observations that employed buoys with thermistors, ADCPs, and two 16.3-MHz Wellen Radar (WERA) HF radars were carried out in the Gulf of Lion in April-June 2006. The observations support the theoretical picture: a pronounced inertial band response occurs only in the presence of shallow stratification and is confined to the mixed layer, and the NIO penetration below the stratified layer is weak. NIO surface magnitude and vertical localization are strongly affected by the presence of even weak density stratification in the upper 10 m. The NIO surface signatures are easily captured by HF radars. Continuous 1.8-yr HF observations near the Porquerolles Island confirm that shallow stratification is indeed the precondition for a strong NIO response. The response sensitivity to stratification provides a foundation for developing HF radar probing of stratification and, indirectly, vertical mixing, including spotting dramatic mixing events and spikes of vertical heat, mass, and momentum exchange. © 2015 American Meteorological Society.

Moutin T.,Aix - Marseille University | Prieur L.,CNRS Oceanography Laboratory of Villefranche
Biogeosciences | Year: 2012

We studied a longitudinal transect in the Mediterranean Sea (MS) and along this transect, the influence of anticyclonic eddies at three long duration (LD) stations. The deep chlorophyll maximum depth, the euphotic layer depth and the top of the nitracline depth are clearly correlated outside of the eddies, and deepen from the oligotrophic western to the ultraoligotrophic eastern MS. We provide evidence that the locations of the three LD stations studied were near the axis of the eddies. Their diameters were close to 100 km and the studied areas were less than 10 km from the centre of the eddies. The positions of the LD stations are marked by an increase in the flux function and a decrease in apparent oxygen utilization (AOU) and in excess density σ), as expected for anticyclonic eddies. Integrated mean primary production measured in situ inside the three studied eddies confirms the previous conclusion that integrated primary production (IPP) about 150 mgC mg-2 dg -1 may appear as a lower limit for IPP during strong oligotrophic conditions. The mesoscale activity is strong enough to locally modify the very well-documented western-to-eastern gradient of trophic conditions in the MS. We proposed a new calculation for mixed layer depths (MLDs) enabling the determination of MLD to take into consideration processes occurring with time scales ranging from a few hours to several days, and also the winter MLD. Studying the main physical, chemical and dynamical characteristics of the three eddies enables us to consider that the vorticity barrier prevents any strong mixing and advection of outer water inside the eddy and explains why the depth range of eddies starts from the surface. As a first approximation, the anticyclonic eddies could be considered as closed systems dating back to the previous winter, making possible to draw first-order budgets. The daily new N-input in the photic zone is virtually identical to the N-export measured at 230 m by drifting traps. This means that the eddies are close to an equilibrium state where input is equal to loss. The annual N-input by winter convection, which is a fundamental criterion for new nutrient availability, may be extremely variable inside eddies, with W-MLD varying from 90.5 m at the western station to 396.5 m at the eastern station. W-MLDs are always deeper inside the eddies than outside where they are in keeping with climatological averages. AOU was low inside the eddies; this together with the near-identical export measured at 230 and 460 m seems to indicate that eddy cores are areas where low mineralisation of particulate organic matter occurs. "In" and "out" AOU comparisons indicate lower mineralisation inside the eddies suggesting a higher efficiency for CO2 sequestration via sedimentation of particulate organic matter. The three eddies are enriched in dissolved organic carbon (DOC). Sequestration of CO2 by vertical export of accumulated DOC therefore seems to be higher inside eddies. The relative importance of DOC transport in the biological pump is probably one of the main characteristics of low-P low chlorophyll (LPLC) areas, and it is likely to be reinforced inside anticyclonic eddies. The numerous anticyclonic eddies in the MS are likely to influence the water masses and their dispersion, and therefore have a strong impact on the biogeochemical properties at the scale of the MS. © Author(s) 2012.

Lacan F.,French National Center for Space Studies | Tachikawa K.,Aix - Marseille University | Jeandel C.,French National Center for Space Studies
Chemical Geology | Year: 2012

A global compilation of the neodymium isotopic composition of seawater is presented. With 880 data points, it confirms the gradual ε Nd increase for intermediate/deep water masses from the northwest North Atlantic, via the Austral and Indian oceans, to the Pacific. This confirms the usefulness of this tracer for studying large scale oceanic circulation. The compilation stresses the need for documenting the oceans south of 30°S, from which less than 4% of the data are derived. The associated neodymium concentrations display heterogeneous vertical gradients among major oceanic basins. In addition to particle remineralization along the global thermohaline circulation, the database suggests that basin size differences also contribute to that heterogeneity. © 2012 Elsevier B.V.

Klimcik C.,Aix - Marseille University
Nuclear Physics B | Year: 2015

We show that the so-called λ deformed σ-model as well as the η deformed one belong to a class of the E-models introduced in the context of the Poisson-Lie-T-duality. The λ and η theories differ solely by the choice of the Drinfeld double; for the λ model the double is the direct product G×. G while for the η model it is the complexified group GC. As a consequence of this picture, we prove for any G that the target space geometries of the λ-model and of the Poisson-Lie T-dual of the η-model are related by a simple analytic continuation. © 2015 The Author.

We present an infinite family of Hamiltonian electromagnetic fluid models for plasmas, derived from drift-kinetic equations. An infinite hierarchy of fluid equations is obtained from a Hamiltonian drift-kinetic system by taking moments of a generalized distribution function and using Hermite polynomials as weight functions of the velocity coordinate along the magnetic guide field. Each fluid model is then obtained by truncating the hierarchy to a finite number N+. 1 of equations by means of a closure relation. We show that, for any positive N, a linear closure relation between the moment of order N+. 1 and the moment of order N guarantees that the resulting fluid model possesses a Hamiltonian structure, thus respecting the Hamiltonian character of the parent drift-kinetic model. An orthogonal transformation is identified which maps the fluid moments to a new set of dynamical variables in terms of which the Poisson brackets of the fluid models become a direct sum and which unveils remarkable dynamical properties of the models in the two-dimensional (2D) limit. Indeed, when imposing translational symmetry with respect to the direction of the magnetic guide field, all models belonging to the infinite family can be reformulated as systems of advection equations for Lagrangian invariants transported by incompressible generalized velocities. These are reminiscent of the advection properties of the parent drift-kinetic model in the 2D limit and are related to the Casimirs of the Poisson brackets of the fluid models. The Hamiltonian structure of the generic fluid model belonging to the infinite family is illustrated treating a specific example of a fluid model retaining five moments in the electron dynamics and two in the ion dynamics. We also clarify the connection existing between the fluid models of this infinite family and some fluid models already present in the literature. © 2015 Elsevier Inc.

Ghosh A.,Saha Institute of Nuclear Physics | Perez A.,Aix - Marseille University
Physical Review Letters | Year: 2011

We present a statistical mechanical calculation of the thermodynamical properties of (nonrotating) isolated horizons. The introduction of the Planck scale allows for the definition of a universal horizon temperature (independent of the mass of the black hole) and a well-defined notion of energy (as measured by suitable local observers) proportional to the horizon area in Planck units. The microcanonical and canonical ensembles associated with the system are introduced. Black hole entropy and other thermodynamical quantities can be consistently computed in both ensembles and results are in agreement with Hawking's semiclassical analysis for all values of the Immirzi parameter. © 2011 American Physical Society.

The viability of Escherichia coli starved of nitrogen (N) or phosphorus (P) decreased by up to seven orders of magnitude during prolonged incubation under aerobic conditions when exposed to high levels of the antibiotic gentamicin, whereas viability of cells starved of carbon (C) was barely affected. However, the initial rate of killing was lower for P-starved cells than for N-starved cells. The transient resistance of P-starved cells was partially dependent upon the expression of the phosphate (Pho) and Cpx responses. Constitutive activity of the Cpx and RpoE (σE) envelope stress regulons increased the resistance of P- and N-starved cells. The level of expression of the RpoE regulon was fourfold higher in P-starved cells than in N-starved cell at the time gentamicin was added. Gentamicin killing of nongrowing cells may thus require ongoing aerobic glucose metabolism and faulty synthesis of structural membrane proteins. However, membrane protein damage induced by gentamicin can be eliminated or repaired by RpoE- and Cpx-dependent mechanisms pre-emptively induced in P-starved cells, which reveals a novel mechanism of resistance to gentamicin that is active in certain circumstances. © 2014 Federation of European Microbiological Societies.

Bedaride N.,Aix - Marseille University | Fernique T.,University of Paris 13
Communications in Mathematical Physics | Year: 2015

Non-periodic tilings and local rules are commonly used to model the long range aperiodic order of quasicrystals and the finite-range energetic interactions that stabilize them. This paper focuses on planar rhombus tilings, which are tilings of the Euclidean plane, which can be seen as an approximation of a real plane embedded in a higher dimensional space. Our main result is a characterization of the existence of local rules for such tilings when the embedding space is four-dimensional. The proof is an interplay of algebra and geometry that makes use of the rational dependencies between the coordinates of the embedded plane. We also apply this result to some cases in a higher dimensional embedding space, notably tilings with n-fold rotational symmetry. © 2015, Springer-Verlag Berlin Heidelberg.

Brovelli A.,Aix - Marseille University
Computational and Mathematical Methods in Medicine | Year: 2012

Granger causality analysis is becoming central for the analysis of interactions between neural populations and oscillatory networks. However, it is currently unclear whether single-trial estimates of Granger causality spectra can be used reliably to assess directional influence. We addressed this issue by combining single-trial Granger causality spectra with statistical inference based on general linear models. The approach was assessed on synthetic and neurophysiological data. Synthetic bivariate data was generated using two autoregressive processes with unidirectional coupling. We simulated two hypothetical experimental conditions: the first mimicked a constant and unidirectional coupling, whereas the second modelled a linear increase in coupling across trials. The statistical analysis of single-trial Granger causality spectra, based on t-tests and linear regression, successfully recovered the underlying pattern of directional influence. In addition, we characterised the minimum number of trials and coupling strengths required for significant detection of directionality. Finally, we demonstrated the relevance for neurophysiology by analysing two local field potentials (LFPs) simultaneously recorded from the prefrontal and premotor cortices of a macaque monkey performing a conditional visuomotor task. Our results suggest that the combination of single-trial Granger causality spectra and statistical inference provides a valuable tool for the analysis of large-scale cortical networks and brain connectivity. Copyright © 2012 Andrea Brovelli.

Ruphy S.,Aix - Marseille University
Simulation and Gaming | Year: 2011

Computer simulations of complex physical objects and processes for which data are very sparse or inexistent have become a major tool of scientific investigation in astrophysics and cosmology. However, one must ask how these simulations acquire their epistemic credentials and whether their realistic ambition is legitimate. A close look at two model-building processes-one in galactic astrophysics, the other in cosmology-reveals heretofore underappreciated features of simulations, such as path dependency. This article argues that such features undermine our confidence in the outcomes of the simulation. Case studies presented here reveal a general tension in computer simulation between realistic ambitions and the possibility of empirical confirmation. The analysis will thus lead to a reassessment of the epistemic goals actually achieved by composite models of complex astrophysical and cosmological phenomena. © 2011 SAGE Publications.

Lugiez D.,Aix - Marseille University
International Journal of Foundations of Computer Science | Year: 2011

Dynamic networks of Pushdown Systems (DNPS in short) have been introduced to perform static analysis of concurrent programs that may spawn threads dynamically. In this model the set of successors of a regular set of configurations can be non-regular, making forward analysis of these models difficult. We refine the model by adding the associative-commutative properties of parallel composition, and we define Presburger weighted tree automata, an extension of weighted automata and tree automata, that accept the set of successors of a regular set of configurations. This yields decidability of the forward analysis of DNPS. Finally, we extend this result to the model where configurations are sets of threads running in parallel. © 2011 World Scientific Publishing Company.

Rovelli C.,Aix - Marseille University | Rovelli C.,University of Toulon
Foundations of Physics | Year: 2014

The world appears to be well described by gauge theories; why? I suggest that gauge is more than mathematical redundancy. Gauge-dependent quantities can not be predicted, but there is a sense in which they can be measured. They describe "handles" though which systems couple: they represent real relational structures to which the experimentalist has access in measurement by supplying one of the relata in the measurement procedure itself. This observation leads to a physical interpretation for the ubiquity of gauge: it is a consequence of a relational structure of physical quantities. © 2013 Springer Science+Business Media New York.

Pellissier H.,Aix - Marseille University
Advanced Synthesis and Catalysis | Year: 2014

This review updates the recent developments in asymmetric aziridination using chiral substrates as well as chiral catalysts, covering the literature since the beginning of 2010. It clearly demonstrates that this reaction constitutes an important tool in organic synthesis, still attracting considerable interest due to the potential use of enantiopure aziridines as useful intermediates in the synthesis of complex important molecules, and to the intriguing biological activities of numerous aziridine-containing compounds including natural products. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dumur F.,Aix - Marseille University | Goubard F.,Cergy-Pontoise University
New Journal of Chemistry | Year: 2014

During the past decade, organic electronics has attracted a great deal of interest due to its applicability in a wide range of applications and high potential for commercial success. These applications notably range from organic light emitting diodes (OLEDs) to organic photovoltaics (OPVs) and sensors. Organic diodes undoubtedly have the potential to redefine many present day lighting solutions if performances and device stability are significantly improved. In these different applications, materials which combine in one molecule a balanced hole and electron transport are currently under intensive research as these materials can ensure an effective exciton recombination or dissociation within the active layer. Over the years, several basic structures have received the attention of researchers for the design of these appealing materials, namely triphenylamines (TPA) and oxadiazoles (OXD) that can respectively act as the hole-transporting and electron-transporting moieties in these ambipolar materials. This review aims at reporting the different OXD-TPA hybrids that have been synthesized to date and to develop a systematic understanding of the structure-property-performance relationships. This journal is © the Partner Organisations 2014.

De Rafael E.,Aix - Marseille University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014

I suggest a new approach to the determination of the hadronic vacuum polarization (HVP) contribution to the anomalous magnetic moment of the muon aμHVP in lattice QCD. It is based on properties of the Mellin transform of the hadronic spectral function and their relation to the HVP self-energy in the Euclidean. I show how aμHVP is very well approximated by a few moments associated to this Mellin transform and how these moments can be evaluated in lattice QCD, providing thus a series of tests when compared with the corresponding determinations using experimental data. © 2014 The Author.

Tassi E.,Aix - Marseille University
European Physical Journal D | Year: 2014

We address the problem of the existence of the Hamiltonian structure for an electrostatic drift-kinetic model and for the related fluid models describing the evolution of the first two moments of the distribution function with respect to the parallel velocity. The drift-kinetic model, which accounts for background density and temperature gradients as well as polarization effects, is shown to possess a noncanonical Hamiltonian structure. The corresponding Poisson bracket is expressed in terms of the fluid moments and it is found that the set of functionals of the zero order moment forms a sub-algebra, thus automatically leading to a class of one-moment Hamiltonian fluid models. In particular, in the limit of weak spatial variations of the background quantities, the Charney-Hasegawa-Mima equation, with its Hamiltonian structure, is recovered. For the set of functionals of the first two moments, which, unlike the case of the Vlasov equation, turns out not to form a sub-algebra, we look for closures that lead to a closed Poisson bracket restricted to this set of functionals. The constraint of the Jacobi identity turns out to select the adiabatic equation of state for an ideal gas with one-degree-of-freedom molecules, as the only admissible closure in this sense. When the so called δf ordering is applied to the model, on the other hand, a Poisson bracket is obtained if the second order moment is a linear combination of the first two moments of the total distribution function. By means of this procedure, three-dimensional Hamiltonian fluid models that couple a generalized Charney-Hasegawa-Mima equation with an evolution equation for the parallel velocity are derived. Among these, a model adopted by Meiss and Horton [Phys. Fluids 26, 990 (1983)] to describe drift waves coupled to ion-acoustic waves, is obtained and its Hamiltonian structure is provided explicitly. © 2014 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.

Santocanale L.,Aix - Marseille University
Information and Computation | Year: 2010

We address the problem of finding nice labellings for event structures of degree 3. We develop a minimum theory by which we prove that the index of an event structure of degree 3 is bounded by a linear function of the height. The main theorem of the paper states that event structures of degree 3 whose causality order is a tree have a nice labelling with 3 colors. We exemplify how to use this theorem to construct upper bounds for the index of other event structures of degree 3. © 2010 Elsevier Inc. All rights reserved.

Santhanam P.,Huntington University | Taieb D.,Aix - Marseille University
Clinical Endocrinology | Year: 2014

18F-FDOPA (6-[18F]-L-fluoro-L-3, 4-dihydroxyphenylalanine)-based PET/CT imaging can be a useful tool for the detection of different neuroendocrine tumours (NETs). 18F-FDOPA is taken up into the cells via the neutral amino acid transporter (LAT1/4F2hc). This transporter is also coupled to the mammalian target of rapamycin (mTOR) signalling pathway. 18F-FDOPA PET/CT may be performed for confirmation of diagnosis of pheochromocytoma/paraganglioma, staging at initial presentation, restaging and follow-up of patients. In SDHx-related syndromes, 18F-FDG PET/CT should be performed in addition to 18F-FDOPA PET/CT. 18F-FDOPA PET/CT is also invaluable in the detection staging/restaging of carcinoid tumours and has greater sensitivity as compared to somatostatin receptor scintigraphy. 18F-FDOPA PET/CT can also distinguish between focal vs diffuse CHI. It is not as useful in adult hyperinsulinism due to increased background uptake, but the problem may be overcome with the help of premedication with carbidopa. It has limited use in pancreatic NETs. 18F-FDOPA PET/CT is a good modality for detection of persistent and residual medullary thyroid cancer (MTC), but 18F-FDG PET/CT may be needed in aggressive tumours. In summary, F-DOPA PET/CT has widespread utility in the diagnosis of different neuroendocrine tumours. © 2014 John Wiley & Sons Ltd.

Issartel J.,Aix - Marseille University | Coiffard C.,Museum fur Naturkunde
Oecologia | Year: 2011

We have examined the extreme longevity displayed by trees in relation to a theory mainly developed in animals, namely, the controversial rate of living (ROL) theory of aging which proposes that longevity is negatively correlated to metabolic rate. Plant metabolism implies respiration and photosynthesis; both are susceptible to negatively impact longevity. The relationship between longevity and metabolism was studied in leaves and stems of several species with the aim of challenging the ROL theory in trees. Leaf and stem life spans were found to be highly correlated to metabolism (R2 = 0.97), and stems displayed a much lower metabolism than leaves. Analysis of covariance (ANCOVA), with metabolism as the covariate, revealed no difference between mean leaf and stem life spans, which would appear to conform to the expectations of the ROL theory. Consequently, the extremely high longevity of trees may be explained by the lower metabolism displayed by the stems. These results clearly reflect different energy allocation and energy expenditure rate strategies between leaves and stems, which may result in different senescence rates (and life spans) in these organs. They also suggest that, in contrast to animals, the ROL theory of aging may apply to woody plants at the organ level, thereby opening a promising new line of research to guide future studies on plant senescence. © 2010 Springer-Verlag.

Leweke T.,Aix - Marseille University
Current Pharmaceutical Biotechnology | Year: 2012

Flow visualization using dye is an inexpensive and easy-to-implement experimental technique. It can be used for a rapid qualitative assessment of fluid flows in configurations relevant to biomedical or biotechnological applications, which often involve small spatial dimensions and flow velocities (low Reynolds numbers). This paper gives an overview of the practical aspects related to dye visualization in liquids (dyes, introduction of dye into the flow, illumination), and discusses the information that can be obtained by this method, which includes the distribution of coherent structures/ vortices, the location of recirculation zones, and certain characteristic spatial and temporal scales. Visualization results for three examples of generic flows related to biomechanical applications are presented: the flow behind a contraction in a pipe (stenosis), the wake of a particle moving along a wall, and the flow inside a lid-driven mixing vessel (bioreactor). © 2012 Bentham Science Publishers.

Faranda D.,French National Center for Scientific Research | Vaienti S.,Aix - Marseille University | Vaienti S.,University of Toulon
Geophysical Research Letters | Year: 2013

In this paper, we analyze several instrumental records of temperatures at different locations by using new techniques originally developed for the analysis of extreme values of dynamical systems. We show that they have the same recurrence time statistics as a chaotic dynamical system perturbed with dynamical noise and by instrument errors. The technique provides a criterion to discriminate whether the recurrence of a certain temperature belongs to the normal variability or can be considered as a genuine extreme event with respect to a specific timescale fixed as parameter. The method gives a self-consistent estimation of the convergence of the statistics of recurrences toward the theoretical extreme value laws. Key Points The method distinguishes between real extremes and natural climate variability The method presents a built-in test of convergence The method is easy to be implemented and fast ©2013. American Geophysical Union. All Rights Reserved.

Caulliez G.,Aix - Marseille University
Journal of Geophysical Research: Oceans | Year: 2013

The dissipation processes affecting short wind waves of centimeter and decimeter scales are investigated experimentally in laboratory. The processes include damping due to molecular viscosity, generation of capillary waves, microbreaking, and breaking. The observations were made in a large wind wave tank for a wide range of fetches and winds, using a laser sheet and a high-resolution video camera. The work aims at constructing a comprehensive picture of dissipative processes in the short wind wave field, to find for which scales particular dissipative mechanism may become important. Four distinct regimes have been identified. For capillary-gravity wave fields, i.e., for dominant waves with scales below 4 cm, viscous damping is found to be the main dissipation mechanism. The gravity-capillary wave fields with dominant wavelength less than 10 cm usually exhibit a train of capillary ripples at the crest wavefront, but no wave breaking. For such waves, the main dissipation process is molecular viscosity occurring through nonlinear energy cascade toward highfrequency motions. Microscale breaking takes place for waves longer than 10 cm and manifests itself in a very localized surface disruption on the forward face of the crest. Such events generate turbulent motions in water and thus enhance wave dissipation. Plunging breaking, characterized by formation of a crest bulge, a microjet hitting the water surface and a splash-up, occurs for short gravitywaves ofwavelength exceeding 20 cm. Macroscale spilling breaking is also observed for longer waves at high winds. In both cases, the direct momentum transfer from breaking waves to the water flow contributes significantly to wave damping. © 2012 American Geophysical Union. All Rights Reserved.

The skeletal plasticity confers the property to record different biological events of life, in particular those occurred during the first years. Due to the development of instrumental analysis for over thirty years, the chemical components analysis of fossils allows us to identify dietary trends to understand the history of food resources management as well as the breastfeeding and weaning practices among ancient societies. After a description of chemical markers used today to restore the past dietary practices, this article aims at presenting a synthesis of the published works and discussing them to underline their advantages and limits.

Mandin P.,Aix - Marseille University | Guillier M.,University Paris Diderot
Current Opinion in Microbiology | Year: 2013

Small regulatory RNAs (sRNAs) are now considered as major post-transcriptional regulators of gene expression in bacteria. Their importance is related to their variety in probably all bacterial species as well as to the extreme diversity of physiological functions of their target genes. An increasing amount of data point to an intimate connection between sRNAs and transcriptional regulatory networks to control multiple functions as important as motility or group behavior. The resulting mixed circuits unravel novel regulatory links and their properties are just starting to be characterized. © 2013 Elsevier Ltd.

Novo D.,De Novo Software | Gregori G.,Aix - Marseille University | Rajwa B.,Purdue University
Cytometry Part A | Year: 2013

Multispectral and hyperspectral flow cytometry (FC) instruments allow measurement of fluorescence or Raman spectra from single cells in flow. As with conventional FC, spectral overlap results in the measured signal in any given detector being a mixture of signals from multiple labels present in the analyzed cells. In contrast to traditional polychromatic FC, these devices utilize a number of detectors (or channels in multispectral detector arrays) that is larger than the number of labels, and no particular detector is a priori dedicated to the measurement of any particular label. This data-acquisition modality requires a rigorous study and understanding of signal formation as well as unmixing procedures that are employed to estimate labels abundance. The simplest extension of the traditional compensation procedure to multispectral data sets is equivalent to an ordinary least-square (LS) solution for estimating abundance of labels in individual cells. This process is identical to the technique employed for unmixing spectral data in various imaging fields. The present study shows that multispectral FC data violate key assumptions of the LS process, and use of the LS method may lead to unmixing artifacts, such as population distortion (spreading) and the presence of negative values in biomarker abundances. Various alternative unmixing techniques were investigated, including relative-error minimization and variance-stabilization transformations. The most promising results were obtained by performing unmixing using Poisson regression with an identity-link function within a generalized linear model framework. This formulation accounts for the presence of Poisson noise in the model of signal formation and subsequently leads to superior unmixing results, particularly for dim fluorescent populations. The proposed Poisson unmixing technique is demonstrated using simulated 8-channel, 2-fluorochrome data and real 32-channel, 6-fluorochrome data. The quality of unmixing is assessed by computing absolute and relative errors, as well as by calculating the symmetrized Kullback-Leibler divergence between known and approximated populations. These results are applicable to any flow-based system with more detectors than labels where Poisson noise is the dominant contributor to the overall system noise and highlight the fact that explicit incorporation of appropriate noise models is the key to accurately estimating the true label abundance on the cells. © 2013 International Society for Advancement of Cytometry.

Zarzoso-Lacoste D.,Aix - Marseille University | Corse E.,Batiment Villemin | Vidal E.,Center Saint Charles | Vidal E.,Center Ird Of Noumea
Molecular Ecology Resources | Year: 2013

While the morphological identification of prey remains in predators' faeces is the most commonly used method to study trophic interactions, many studies indicate that this method does not detect all consumed prey. Polymerase chain reaction-based methods are increasingly used to detect prey DNA in the predator food bolus and have proven efficient, delivering highly accurate results. When studying complex diet samples, the extraction of total DNA is a critical step, as polymerase chain reaction (PCR) inhibitors may be co-extracted. Another critical step involves a careful selection of suitable group-specific primer sets that should only amplify DNA from the targeted prey taxon. In this study, the food boluses of five Rattus rattus and seven Rattus exulans were analysed using both morphological and molecular methods. We tested a panel of 31 PCR primer pairs targeting bird, invertebrate and plant sequences; four of them were selected to be used as group-specific primer pairs in PCR protocols. The performances of four DNA extraction protocols (QIAamp® DNA stool mini kit, DNeasy® mericon food kit and two of cetyltrimethylammonium bromide-based methods) were compared using four variables: DNA concentration, A260/A280 absorbance ratio, food compartment analysed (stomach or faecal contents) and total number of prey-specific PCR amplification per sample. Our results clearly indicate that the A260/A280 absorbance ratio, which varies between extraction protocols, is positively correlated to the number of PCR amplifications of each prey taxon. We recommend using the DNeasy® mericon food kit (QIAGEN), which yielded results very similar to those achieved with the morphological approach. © 2013 Blackwell Publishing Ltd.

Lagier J.-C.,Aix - Marseille University | Lagier J.-C.,Marseille University Hospital Center
Clinical Microbiology and Infection | Year: 2014

Recurrent Clostridium difficile infections constitute an important medical concern. Evidence has been provided showing that faecal microbiota transplantation is a more efficient treatment than antibiotics. Serious side effects are unusual, and acceptability is not an obstacle. Nevertheless, protocols are heterogeneous with respect to the selection of donors and the methodology used for the faecal transplantation. Regulations by both the Food and Drug Administration and the French authorities consider stool samples to be drugs, and suggest strict supervision in clinical trials. Donor screening by questionnaire or by blood and stool analysis, which is essential in eliminating pathogens or viruses before transplantation, is similar in different countries, with a few exceptions. The traceability of the faecal transplant and long-term follow-up of the patients in clinical trials are issues that may be difficult to organize. The use of frozen microbiota facilitates transplantation, and the nasogastric route seems to be at least as effective as other invasive methods and avoids the risk of anaesthesia. Synthetic microbiota is an approach that selects a mixture of bacteria, thereby eliminating the risk of transmissible disease; however, this approach is not yet evidence-based. The use of pills, which is currently being tested in clinical trials, will certainly be the starting point for the extensive use and wide industrialization of faecal microbiota transplantation. © 2014 European Society of Clinical Microbiology and Infectious Diseases.

Andre N.,Service dHematologie and Oncologie Pediatrique | Carre M.,Aix - Marseille University | Pasquier E.,University of New South Wales
Nature Reviews Clinical Oncology | Year: 2014

Since its inception in 2000, metronomic chemotherapy has undergone major advances as an antiangiogenic therapy. The discovery of the pro-immune properties of chemotherapy and its direct effects on cancer cells has established the intrinsic multitargeted nature of this therapeutic approach. The past 10 years have seen a marked rise in clinical trials of metronomic chemotherapy, and it is increasingly combined in the clinic with conventional treatments, such as maximum-tolerated dose chemotherapy and radiotherapy, as well as with novel therapeutic strategies, such as drug repositioning, targeted agents and immunotherapy. We review the latest advances in understanding the complex mechanisms of action of metronomic chemotherapy, and the recently identified factors associated with disease resistance. We comprehensively discuss the latest clinical data obtained from studies performed in both adult and paediatric populations, and highlight ongoing clinical trials. In this Review, we foresee the future developments of metronomic chemotherapy and specifically its potential role in the era of personalized medicine. © 2014 Macmillan Publishers Limited. All rights reserved.

Lopez D.,Aix - Marseille University | Lauga E.,University of Cambridge
Physics of Fluids | Year: 2014

Flagellated bacteria exploiting helical propulsion are known to swim along circular trajectories near surfaces. Fluid dynamics predicts this circular motion to be clockwise (CW) above a rigid surface (when viewed from inside the fluid) and counterclockwise (CCW) below a free surface. Recent experimental investigations showed that complex physicochemical processes at the nearby surface could lead to a change in the direction of rotation, both at solid surfaces absorbing slip-inducing polymers and interfaces covered with surfactants. Motivated by these results, we use a far-field hydrodynamic model to predict the kinematics of swimming near three types of interfaces: clean fluid-fluid interface, slipping rigid wall, and a fluid interface covered by incompressible surfactants. Representing the helical swimmer by a superposition of hydrodynamic singularities, we first show that in all cases the surfaces reorient the swimmer parallel to the surface and attract it, both of which are a consequence of the Stokes dipole component of the swimmer flow field. We then show that circular motion is induced by a higher-order singularity, namely, a rotlet dipole, and that its rotation direction (CW vs. CCW) is strongly affected by the boundary conditions at the interface and the bacteria shape. Our results suggest thus that the hydrodynamics of complex interfaces provide a mechanism to selectively stir bacteria. © 2014 AIP Publishing LLC.

Saccadic inhibition refers to the strong temporary decrease in saccadic initiation observed when a visual distractor appears shortly after the onset of a saccadic target. Here, to gain a better understanding of this phenomenon, we assessed whether saccade amplitude changes could accompany these modulations of latency distributions. As previous studies on the saccadic system using visual backward masking-a protocol in which the mask appears shortly after the target-showed latency increases and amplitude changes, we suspected that this could be a condition in which amplitude changes would accompany saccadic inhibition. We show here that visual backward masking produces a strong saccadic inhibition. In addition, this saccadic inhibition was accompanied by large and complex amplitude changes: a first phase of gain decrease occurred before the saccadic inhibition; when saccades reappeared after the inhibition, they were accurate before rapidly entering into a second phase of gain decrease. We observed changes in saccade kinematics that were consistent with the possibility of saccades being interrupted during these two phases of gain decrease. These results show that the onset of a large stimulus shortly after a first one induces the previously reported saccadic inhibition, but also induces a complex pattern of amplitude changes resulting from a dual amplitude perturbation mechanism with fast and slow components © 2012 ARVO.

Vlieghe P.,Vect Horus S.A.S. | Khrestchatisky M.,Aix - Marseille University | Khrestchatisky M.,French National Center for Scientific Research
Medicinal Research Reviews | Year: 2013

The central nervous system (CNS) is protected by various barriers, which regulate nervous tissue homeostasis and control the selective and specific uptake, efflux, and metabolism of endogenous and exogenous molecules. Among these barriers is the blood-brain barrier (BBB), a physical and physiological barrier that filters very efficiently and selectively the entry of compounds from the blood to the brain and protects nervous tissue from harmful substances and infectious agents present in the bloodstream. The BBB also prevents the entry of potential drugs. As a result, various drug targeting and delivery strategies are currently being developed to enhance the transport of drugs from the blood to the brain. Following a general introduction, we briefly overview in this review article the fundamental physiological properties of the BBB. Then, we describe current strategies to bypass the BBB (i.e., invasive methods, alternative approaches, and temporary opening) and to cross it (i.e., noninvasive approaches). This section is followed by a chapter addressing the chemical and technological solutions developed to cross the BBB. A special emphasis is given to prodrug-targeting approaches and targeted nanotechnology-based systems, two promising strategies for BBB targeting and delivery of drugs to the brain. © 2012 Wiley Periodicals, Inc.

Evans B.W.,University of Washington | Hattori K.,University of Ottawa | Baronnet A.,Aix - Marseille University
Elements | Year: 2013

Rock-forming serpentine minerals form flat, cylindrical, and corrugated crystal microstructures, which reflect energetically efficient layering of alternate tetrahedral and octahedral sheets. Serpentinization of peridotite involves internal buffering of the pore fluid, reduction of oxygen fugacity, and partial oxidation of Fe2+ to Fe3+. Sluggish MgFe diffusion in olivine causes precipitation of magnetite and release of H 2. The tectonic environment of the serpentinization process dictates the abundance of fluid-mobile elements in serpentinites. Similar enrichment patterns of fluid-mobile elements in mantle-wedge serpentinites and arc magmas suggest a linkage between the dehydration of serpentinite and arc magmatism.

Vey N.,Aix - Marseille University
Interdisciplinary Topics in Gerontology | Year: 2013

The prognosis of acute myeloid leukemia (AML) in the elderly is poor with overall less than 5% of the patients expected to be alive after 5 years. In many studies, age was an independent poor prognostic factor. In the elderly, the frequency of secondary forms of AML, of unfavorable cytogenetics, expression of multidrug resistance genes in part explains the poor outcome. However, based on genetic and molecular studies, there is no evidence for specific biological features of the disease in the elderly. Host-related factors including comorbidity and reduced functional reserves also account for the severity of the disease. Finally, population-based studies show that approximately 30% of patients older than 65 years are offered intensive chemotherapy. This chapter summarizes the recent advances in the biology of AML, in particular the impact of new molecular markers. An overview of the studies that have evaluated comorbidities and results of geriatric assessments in these patients are also presented. Copyright © 2013 S. Karger AG, Basel.

Blumlein J.,German Electron Synchrotron | Brunner J.,German Electron Synchrotron | Brunner J.,Aix - Marseille University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2011

We re-analyze published proton beam dump data taken at the U70 accelerator at IHEP Serpukhov with the ν-calorimeter I experiment in 1989 to set mass-coupling limits for dark gauge forces. The corresponding data have been used for axion and light Higgs particle searches in Blümlein et al. (1991, 1992) [1,2] before. We determine new mass and coupling exclusion bounds for dark gauge bosons. © 2011 Elsevier B.V.

Mochizuki K.,Aix - Marseille University
Nuclear and Particle Physics Proceedings | Year: 2016

For many physics analyses at the LHC, the ability to identify jets containing B-hadrons (b-tagging) is one of the most crucial ingredients. After a brief review of the b-tagging algorithms developed in the ATLAS experiment, we present the refined b-jet tagging efficiency measurement with a combinatorial likelihood approach, a novel c-jet tagging efficiency measurement using W boson production in association with a c-quark, and the updates of c- and light-jet tagging efficiency measurements with increased statistics. © 2016 .

More than 40 years of scientific investigations of the hominin bearing Plio-Pleistocene sediments of northern Tanzania have provided a number of paleobotanical data, which, taken as a whole, provide today a way to investigate vegetation changes between 4 and 1 Ma, at a time when our early ancestors emerged. Here, I have integrated the data from all vegetation proxies obtained for the paleontological sites of Laetoli, Olduvai, and Peninj (i.e. macroscopic plant remains, pollen and phytolith assemblages, carbon and oxygen isotopic ratios measured on carbonates, and organic biomarkers). This important, yet discontinuous botanical record suggests some similarities between past and present-day vegetation at the regional scale: Afromontane forests with Olea, Podocarpus, Juniperus, Hagenia abyssinica in the highlands, and wooded grasslands with grasses and drought-adapted Acacia, Commiphora, Capparidaceae, and Chenopodiaceae and/or Amaranthaceae in the lowlands were present in the southern Serengeti-Crater Highlands region since 4 Ma. Grasses of the C4 photosynthetic type made their first appearance in the record at ~3.7 Ma, i.e. during the mid-Pliocene, ~700 ky before major pCO2 and temperature decline. C4 grasses became dominant in the vegetation soon after (~3.66 Ma), probably in response to reduced precipitation. At ~2.6 Ma, phytolith and isotope indicate grassland with abundant C4 xerophytic grasses that document strong aridity during the Intensification of Northern Hemisphere Glaciation period (~2.7-2.5 Ma). After 2 Ma, the detailed and diverse record at Olduvai indicates complex vegetation patterns linked to oscillating precipitation, varying lake levels, and the presence of geological faults. Hence, despite low (basin-averaged) reconstructed paleo-precipitation amounts of ~250-700 mm/y, C4-grasslands, closed woodlands, wetlands, and palm-groves co-occurred on short spatial scales near saline Lake Olduvai. Freshwater wetlands and palm-rich woodlands occurred in highly localized areas on the lake margins, where aquifer barriers and/or outcrops caused by geologic faults allowed groundwater discharge. Botanical evidence of paleo-springs at Laetoli, Olduvai, and Peninj includes the marked presence of Typha (cattail) and Hyphaene (palm tree) in association with Acacia pollen grains, and (at Olduvai) abundant forest indicator phytoliths and organic and isotopic biomarkers. At Olduvai, freshwater wetlands were most developed when lake level and fluvial competence where low, i.e. during dry periods. When wet-dry climate variability was extreme in East Africa (~1.9-1.7 Ma), freshwater springs may therefore have offered a sustainable habitat (i.e. refuge) for several species, including hominins, and favored hominin and artifact concentration at these specific places, particularly during environmentally stressful times. © 2014 Elsevier Ltd and INQUA.

Benedetti L.C.,Aix - Marseille University | Van Der Woerd J.,University of Strasbourg
Elements | Year: 2014

When the recurrence intervals of large earthquakes span several thousands of years, the dating of fault movements over long time intervals is essential for estimating the next event. Constraining the age of faulting, earthquake recurrence, or toppled rocks is especially important for determining if a fault is likely to break again soon. In recent years, cosmogenic nuclides have provided new insights into the dating of these ground movements. Approaches to gathering this information can be direct, such as dating fault surfaces with 36Cl, or indirect, such as dating fault-offset alluvial fans with 10Be or 26Al. New results from these methods are certain to better defi ne the tectonic and seismic hazards in areas with increasing population density.

El Far O.,French Institute of Health and Medical Research | Seagar M.,Aix - Marseille University
Journal of Neurochemistry | Year: 2011

SNARE (soluble N-ethylmaleimide sensitive factor attachment protein receptors)-mediated exocytotic release of neurotransmitters is a key process in neuronal communication, controlled by a number of molecular interactions. A synaptic vesicle v-SNARE protein (VAMP2 or synaptobrevin), in association with two plasma membrane t-SNAREs (syntaxin 1 and SNAP25), assemble to form a protein complex that is largely accepted as the minimal membrane fusion machine. Acidification of the synaptic vesicle lumen by the large multi-subunit vacuolar proton pump (V-ATPase) is required for loading with neurotransmitters. Recent data demonstrate a direct interaction between the c-subunit of the V-ATPase and VAMP2 that appears to play a role at a late step in transmitter release. In this review, we examine evidence suggesting that the V0 membrane sector of the V-ATPase not only participates in proton pumping, but plays a second distinct role in neurosecretion, downstream of filling and close to vesicle fusion. © 2011 The Authors.

Timsit Y.,Aix - Marseille University
Nucleic Acids Research | Year: 2011

Type II topoisomerases are ubiquitous enzymes that control the topology and higher order structures of DNA. Type IIA enzymes have the remarkable property to sense locally the global DNA topology. Although many theoretical models have been proposed, the molecular mechanism of chiral discrimination is still unclear. While experimental studies have established that topoisomerases IIA discriminate topology on the basis of crossover geometry, a recent single-molecule experiment has shown that the enzyme has a different processivity on supercoiled DNA of opposite sign. Understanding how cross-over geometry influences enzyme processivity is, therefore, the key to elucidate the mechanism of chiral discrimination. Analysing this question from the DNA side reveals first, that the different stability of chiral DNA cross-overs provides a way to locally sense the global DNA topology. Second, it shows that these enzymes have evolved to recognize the G- and T-segments stably assembled into a right-handed cross-over. Third, it demonstrates how binding right-handed cross-overs across their large angle imposes a different topological link between the topoIIA rings and the plectonemes of opposite sign thus directly affecting the enzyme freedom of motion and processivity. In bridging geometry and kinetic data, this study brings a simple solution for type IIA topoisomerase chiral discrimination. © 2011 The Author(s).

Sereno M.,Polytechnic University of Turin | Sereno M.,National Institute of Nuclear Physics, Italy | Paraficz D.,Aix - Marseille University
Monthly Notices of the Royal Astronomical Society | Year: 2013

Time delays between multiple images of lensed sources can probe the geometry of the universe. We propose a novel method based on free-form modelling of gravitational lenses to estimate time delay distances and, in turn, cosmological parameters. This approach does not suffer from the degeneracy between the steepness of the profile and the cosmological parameters. We apply the method to 18 systems having time delay measurements and find H0 = 69 ± 6(stat.) ± 4(syst.) km s-1Mpc-1. In combination with Wilkinson Microwave Anisotropy Probe 9, the constraints on dark energy are ωw = 0.68 ± 0.05 and w =-0.86 ± 0.17 in a flat model with constant equation of state. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. Published by Oxford University Press on behalf of the Royal Astronomical Society.

Hohener P.,Aix - Marseille University | Atteia O.,ENSEGID
Geochimica et Cosmochimica Acta | Year: 2014

In isotope geochemistry, the Rayleigh equation describes the evolution of isotope ratios in a parent compound as a function of reaction progress, and associated equations describe isotope ratios in an instantaneous product and an accumulated product. The Rayleigh equation is commonly used for fitting fractionation factors of processes undergoing kinetic isotope fractionation such as biochemical reactions. This work extends the equations associated with the Rayleigh equation for describing the isotope ratios in intermediate products in a chain of reacting species degrading with first-order kinetics. A general solution is presented for decay chains of any length, and explicit examples are presented for the biodegradation of a substrate or a mixture of substrates through 3 intermediate products to a final product. Applications of these analytical solutions for the fitting of enrichment factors for intermediate compounds in laboratory experiments are demonstrated with a spreadsheet. This avoids separate experiments to measure each intermediate product. The utility of the equations for the assessment of slopes in dual isotope plots is furthermore illustrated, and limitations of its use are critically discussed. © 2013 Elsevier Ltd.

A radiocarbon-dated sequence at Gemenos, near Marseille, has provided Pleniglacial and Holocene molluscan assemblages. The Pleniglacial succession shows only small specific changes within a malacofauna, in the main, common in periglacial deposits of south-eastern France. In the Middle Pleniglacial part of the sequence, a colluvial level dated to 38,690 Plusmn; 790 BP probably corresponds to a minor climate improvement during the marine isotopic stage (MIS) 3, potentially one of the oscillations of the Moershoofd-Pile interstadial complex. A deterioration then leads to loess accumulation with assemblages typical of cold open environments. A layer dated to 32,230 Plusmn; 490 BP appears to be only marked by an increase of humidity. It could be related to the Hengelo-Charbon interstadial. This is followed by a non-dated arid and cold phase characterized by aeolian sands that contain a very poor fauna. It may represent an undefined event in MIS 2. The subsequent warming phase is not dated, but its assemblages, in which both cold tolerant and thermophilous species can be found, are representative of the Early Holocene between 10,000 and 9,000 BP Finally, the last levels of the sequence contain Late Holocene assemblages (ca. 4,000 BP) including several synanthropic Mediterranean snails. The present findings contradict the assumptions that the open-country snail Pupilla muscorum (which today is rather hygrophilous in the Mediterranean area) is not to be found in the loess of Provence, and that there is a climate-related biogeographic gradient within the malacofauna of the "Wurmian" loess in south-eastern France with more xerophilic and Mediterranean assemblages near the littoral. A comparison with other MIS 3 land snail assemblages in Provence suggests a more complex regional pattern which remains difficult to comprehend owing to the lack of dated and well developed sequences in the different sub-regions of south-eastern France.

Zafar T.,Aix - Marseille University | Watson D.,Copenhagen University
Astronomy and Astrophysics | Year: 2013

Among the key parameters defining the interstellar media (ISM) of galaxies is the fraction of the metals that are locked up in dust: the metals-to-dust ratio. This ratio bears not only on the ISM and its evolution, but also particularly on the origin of cosmic dust. We combine extinction and abundance data from γ-ray burst (GRB) afterglows with similar data from quasar (QSO) foreground absorbers, as well as from multiply-imaged galaxy-lensed QSOs, to determine the metals-to-dust ratios for lines of sight through a wide diversity of galaxies from blue, dwarf starbursts to massive ellipticals, across a vast range of redshifts z = 0.1-6.3, and nearly three orders of magnitude of column density and metal abundance. The GRB and lensed QSO extinction methods are the most reliable that are available outside the Local Group (LG), allowing absolute extinction measurements. We thus determine the metals-to-dust ratio in a unique way, providing direct determinations of in situ gas and dust columns without recourse to assumptions with large uncertainties. We find that the metals-to-dust ratios in these systems are surprisingly close to the value for the LG, with a mean value of 1021.2 cm-2 AV mag-1 and a standard deviation of 0.3 dex, compared to the Galactic value of 1021.3 cm-2AV mag-1 (in units of the Galactic gas-to-dust ratio). There is no evidence of deviation from this mean ratio as a function of metallicity, even down to our lowest metallicity of 0.01 Z/Z⊙. The lack of any obvious dependence of the metals-to-dust ratio on column density, galaxy type or age, redshift, or metallicity indicates a close correspondence between the formation of the metals and the formation of dust. Any delay between the formation of metals and dust must be shorter than the typical metal-enrichment times of these galaxies, i.e. shorter than a few Myr. Formation of the bulk of the dust in low mass stars is therefore ruled out by these data at any cosmic epoch. Furthermore, dust destruction must not dominate over formation/growth in virtually any galaxy environment. The close correlation between metals and dust is a natural consequence of the formation of the bulk of cosmic dust in supernovae. Grain growth in the ISM, if it is to be the dominant cosmic dust formation mechanism, is strongly constrained by these data to operate on very short timescales. © ESO, 2013.

Bertrand V.,Aix - Marseille University
Wiley Interdisciplinary Reviews: Developmental Biology | Year: 2016

The Wnt/β-catenin pathway plays key roles during animal development. In several species, β-catenin is used in a reiterative manner to regulate cell fate diversification between daughter cells following division. This binary cell fate specification mechanism has been observed in animals that belong to very diverse phyla: the nematode Caenorhabditis elegans, the annelid Platynereis, and the ascidian Ciona. It may also play a role in the regulation of several stem cell lineages in vertebrates. While the molecular mechanism behind this binary cell fate switch is not fully understood, it appears that both secreted Wnt ligands and asymmetric cortical factors contribute to the generation of the difference in nuclear β-catenin levels between daughter cells. β-Catenin then cooperates with lineage specific transcription factors to induce the expression of novel sets of transcription factors at each round of divisions, thereby diversifying cell fate. © 2016 Wiley Periodicals, Inc.

Rovelli C.,Aix - Marseille University | Rovelli C.,University of Toulon | Wilson-Ewing E.,Louisiana State University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2014

We point out that the relative Heisenberg uncertainty relations vanish for noncompact spaces in homogeneous loop quantum cosmology. As a consequence, for sharply peaked states quantum fluctuations in the scale factor never become important, even near the bounce point. This shows why quantum backreaction effects remain negligible and explains the surprising accuracy of the effective equations in describing the dynamics of sharply peaked wave packets. This also underlines the fact that minisuperspace models - where it is global variables that are quantized - do not capture the local quantum fluctuations of the geometry. © 2014 American Physical Society.

Herrscher E.,Aix - Marseille University | Le Bras-Goude G.,University of Bordeaux 1
American Journal of Physical Anthropology | Year: 2010

The Middle Neolithic of the Northwestern Mediterranean area (∼4500-3500 BC cal) is characterized by the development of food production techniques as well as by increasing social complexity. These characteristics could have had an impact on human dietary patterns. To evaluate human dietary practices and lifeways of the Middle Neolithic populations from the South of France, stable carbon and nitrogen isotope analysis was carried out on 57 human and 53 faunal bones from seven archaeological sites located in the Languedoc and Garonne regions between 20 and 100 km from the Mediterranean Sea, respectively. Results show regional differences in carbon isotope values. Animal and human bones from the Languedoc region are significantly enriched in 13C relative to the Garonne. Conversely, human and dog bones from the Garonne region are significantly enriched in 15N compared to human and dog bones from the Languedoc region. These results highlight the importance of the local ecosystem in human and animal diet as well as a regional differentiation of palaeodietary behavior, which probably relates to economic and social factors. The comparison of stable isotope data with archaeological and biological evidence does not show any significant intra- or interpopulation differences. However, the presence of human outliers suggests that migration probably occurred, perhaps in relation to the trade of animals and/or materials. This study also highlights the importance of investigating local animal stable isotope values for the interpretation of human palaeodiet. © 2009 Wiley-Liss, Inc.

Tachikawa K.,Aix - Marseille University | Piotrowski A.M.,University of Cambridge | Bayon G.,French Research Institute for Exploitation of the Sea
Quaternary Science Reviews | Year: 2014

Neodymium isotopic ratios in marine environments have been used as a tracer of water masses and exchange processes between dissolved and particulate phases. The interest in this tracer has been growing with improvement of our knowledge on its chemical behaviour in the modern ocean and the identification of sedimentary phases that preserve past seawater e{open}Nd values. In the last few decades the Nd isotopic composition measured on Fe-Mn crusts, sediment leachates, bulk carbonate fraction, corals and fish teeth have been increasingly interpreted in the context of understanding the role of the ocean in paleoclimate changes. In particular, calcareous foraminiferal tests (shells) have acquired increasing attention as an archive of seawater Nd isotopic signatures, because it allows continuous high-resolution records to be measured and directly compared to other proxies including stable isotopes and trace metals. The main challenge of interpreting the Nd isotopic composition of foraminifera is determining the origin of the Nd preserved within them. In this review, we present an overview of methodological progress including that of bulk foraminifera and microanalyses within foraminiferal tests, as well as geochemical meaning of extracted Nd concentrations and isotopic compositions. The growing body of evidence suggests that Nd isotopic signatures of sedimentary planktonic foraminifera correspond to bottom water values rather than surface water ones. The Nd-rich phases associated with sedimentary foraminifera are adhesive nano-scale particles of Mn and Fe oxides and hydroxides, and Mn-rich carbonates formed within layers of foraminiferal calcite. Mechanical cleaning to remove clay minerals is likely to be sufficient in most cases to reconstruct past bottom water circulations. Unresolved issues include the potential influence of pore water Nd on e{open}Nd values extracted from sedimentary foraminiferal tests under different sedimentalogical and oceanographic conditions. © 2013 Elsevier Ltd.

Meunier P.-E.,Aix - Marseille University
Theoretical Computer Science | Year: 2016

We provide a mathematical proof that a large number of elementary cellular automata are computationally simple. This work is the first systematic classification of elementary cellular automata based on a formal notion of computational complexity.It contrasts with previous approaches in the simplicity of the method - most proofs are just a few lines long and require no heavy computational explorations. More importantly, this type of short proof not only provides evidence for the presence of simple patterns, it also provides reasons for this simplicity.Moreover, thanks to the generality of communication complexity, we hope that this work finds new applications to other natural systems such as neural networks and gene regulatory networks, in particular for real data. © 2016.

Gleyzes J.,CEA Saclay Nuclear Research Center | Gleyzes J.,French National Center for Scientific Research | Langlois D.,University Paris - Sud | Piazza F.,University Paris - Sud | And 4 more authors.
Physical Review Letters | Year: 2015

We introduce a new class of scalar-tensor theories of gravity that extend Horndeski, or "generalized Galileon," models. Despite possessing equations of motion of higher order in derivatives, we show that the true propagating degrees of freedom obey well-behaved second-order equations and are thus free from Ostrogradski instabilities, in contrast to standard lore. Remarkably, the covariant versions of the original Galileon Lagrangians - obtained by direct replacement of derivatives with covariant derivatives - belong to this class of theories. These extensions of Horndeski theories exhibit an uncommon, interesting phenomenology: The scalar degree of freedom affects the speed of sound of matter, even when the latter is minimally coupled to gravity. © 2015 American Physical Society.

Rovelli C.,Aix - Marseille University | Vidotto F.,Radboud University Nijmegen
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

We study the quantization of geometry in the presence of a cosmological constant, using a discretization with constant-curvature simplices. Phase space turns out to be compact and the Hilbert space finite dimensional for each link. Not only the intrinsic, but also the extrinsic geometry turns out to be discrete, pointing to the discreteness of time, in addition to space. We work in 2+1 dimensions, but these results may be relevant also for the physical 3+1 case. © 2015 American Physical Society.

Boulet L.-P.,Laval University | Chanez P.,Aix - Marseille University
Current Opinion in Allergy and Clinical Immunology | Year: 2015

Purpose of review To determine the benefits of new asthma drugs or therapies, they should be assessed with regard to their effects on relevant clinical outcomes. Recent findings The most frequently used outcomes have been symptoms, rescue medication needs and pulmonary function tests, although others such as quality of life, exacerbations and impairment of activities have also been identified as important ones. Improvements in our understanding of basic mechanisms of asthma have led to the development of new sets of outcomes including inflammatory markers and a rapidly increasing number of biomarkers, which however require validation, and assessment of their clinical usefulness. Many studies have not only looked at induced sputum cell differentials or F E NO to phenotype asthma but also as treatment efficacy markers. Periostin is considered a marker of TH2-induced airway inflammation and a predictor of response to drugs such as anti-IL13 and omalizumab, although at the individual level, such prediction remains imperfect. Summary There is a need to develop new markers of activity of the disease, with a prognostic value with regard to the benefits of new treatments. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.

Guglielmi Y.,Aix - Marseille University | Cappa F.,University of Nice Sophia Antipolis
Geomorphology | Year: 2010

Recurring large rock-slope failures of the Argentera-Mercantour massif (southern French Alps) over the past 20,000 years were identified in the field and analyzed using a continuum mechanics approach based on material weakening in a three-dimensional finite-difference model. We compared a mountain-slope failure model neglecting the effect of rock strength loss with a model simulating the effect of strength loss and integrating cohesional weakening and frictional strengthening processes. The good correspondence between the relative chronology and location of observed and simulated deformations shows that (1) the gradual loss of rock mass strength related to stress release effects following the Pleistocene deglaciation can be as long as several thousands of years, and (2) the causes and triggering of the present-day active landslides are related to this long failure history. Our study suggests that the episodic nature of massive rock slides can be explained through the gradual development of tensile and shear failure, and time-dependent strength degradation. Our numerical model is a good reproduction of large landslides at the regional-scale of a mountainous massif. © 2009 Elsevier B.V. All rights reserved.

Dessart L.,Aix - Marseille University | Hillier D.J.,University of Pittsburgh | Waldman R.,Hebrew University of Jerusalem | Livne E.,Hebrew University of Jerusalem
Monthly Notices of the Royal Astronomical Society | Year: 2013

We explore the properties of Type II-Plateau (II-P) supernovae (SNe) together with their red supergiant (RSG) star progenitors. Using MESA STAR, we modulate the parameters (e.g. mixing length, overshoot, rotation, metallicity) that control the evolution of a 15Mȯ mainsequence star to produce a variety of physical pre-SN models and SN II-P ejecta. We extend previous modelling of SN II-P radiation to include photospheric and nebular phases, as well as multiband light curves and spectra. Our treatment does not assume local thermodynamic equilibrium, is time dependent, treats explicitly the effects of line blanketing and incorporates non-thermal processes. We find that the colour properties of SNe II-P require large model atoms for Fe I and Fe II, much larger than previously adopted. The colour properties also imply RSG progenitors of limited extent (~500 Rȯ) -larger progenitor stars produce an SN II-P radiation that remains too blue for too long. This finding calls for a reduction of RSG radii, perhaps through a strengthening of convective energy transport in RSG envelopes. Increased overshoot and rotation reduce the ratio of ejecta to helium-core mass, similarly to an increase in main-sequence mass, and thus complicate the inference of progenitor masses. In contrast to the great sensitivity on progenitor radius, SN II-P colour evolution appears insensitive to variations in explosion energy. Finally, we document the numerous SN II-P signatures that vary with progenitor metallicity, revealing their potential for metallicity determinations in the nearby and distant Universe.

Goldrick M.,Northwestern University | Runnqvist E.,Aix - Marseille University | Costa A.,University Pompeu Fabra
Psychological Science | Year: 2014

It is well known that multilingual speakers' nonnative productions are accented. Do these deviations from monolingual productions simply reflect the mislearning of nonnative sound categories, or can difficulties in processing speech sounds also contribute to a speaker's accent? Such difficulties are predicted by interactive theories of production, which propose that nontarget representations, partially activated during lexical access, influence phonetic processing. We examined this possibility using language switching, a task that is well known to disrupt multilingual speech production. We found that these disruptions extend to the articulation of individual speech sounds. When native Spanish speakers are required to unexpectedly switch the language of production between Spanish and English, their speech becomes more accented than when they do not switch languages (particularly for cognate targets). These findings suggest that accents reflect not only difficulty in acquiring second-language speech sounds but also the influence of representations partially activated during on-line speech processing. © The Author(s) 2014.

Alric J.,University Pierre and Marie Curie | Alric J.,Aix - Marseille University
Biochimica et Biophysica Acta - Bioenergetics | Year: 2014

In oxygenic photosynthesis, cyclic electron flow around photosystem I denotes the recycling of electrons from stromal electron carriers (reduced nicotinamide adenine dinucleotide phosphate, NADPH, ferredoxin) towards the plastoquinone pool. Whether or not cyclic electron flow operates similarly in Chlamydomonas and plants has been a matter of debate. Here we would like to emphasize that despite the regulatory or metabolic differences that may exist between green algae and plants, the general mechanism of cyclic electron flow seems conserved across species. The most accurate way to describe cyclic electron flow remains to be a redox equilibration model, while the supramolecular reorganization of the thylakoid membrane (state transitions) has little impact on the maximal rate of cyclic electron flow. The maximum capacity of the cyclic pathways is shown to be around 60 electrons transferred per photosystem per second, which is in Chlamydomonas cells treated with 3(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) and placed under anoxic conditions. Part I of this work (aerobic conditions) was published in a previous issue of BBA-Bioenergetics (vol. 1797, pp. 44-51) (Alric et al., 2010). © 2014 Elsevier B.V.

Jones T.,California Institute of Technology | Ellis R.S.,California Institute of Technology | Richard J.,University of Lyon | Jullo E.,Aix - Marseille University
Astrophysical Journal | Year: 2013

We present and discuss measurements of the gas-phase metallicity gradient in four gravitationally lensed galaxies at z = 2.0-2.4 based on adaptive optics-assisted imaging spectroscopy with the Keck II telescope. Three galaxies with well-ordered rotation reveal metallicity gradients with lower gas-phase metallicities at larger galactocentric radii. Two of these display gradients much steeper than found locally, while a third has one similar to that seen in local disk galaxies. The fourth galaxy exhibits complex kinematics indicative of an ongoing merger and reveals an "inverted" gradient with lower metallicity in the central regions. By comparing our sample to similar data in the literature for lower redshift galaxies, we determine that, on average, metallicity gradients must flatten by a factor of 2.6 ± 0.9 between z = 2.2 and the present epoch. This factor is in rough agreement with the size growth of massive galaxies, suggesting that inside-out growth can account for the evolution of metallicity gradients. Since the addition of our new data provides the first indication of a coherent picture of this evolution, we develop a simple model of chemical evolution to explain the collective data. We find that metallicity gradients and their evolution can be explained by the inward radial migration of gas together with a radial variation in the mass loading factor governing the ratio of outflowing gas to the local star formation rate. Average mass loading factors of ≲ 2 are inferred from our model in good agreement with direct measurements of outflowing gas in z ≃ 2 galaxies. © 2013. The American Astronomical Society. All rights reserved.

Vacher H.,French Institute of Health and Medical Research | Vacher H.,Aix - Marseille University | Trimmer J.S.,University of California at Davis
Pflugers Archiv European Journal of Physiology | Year: 2011

Voltage-gated ion channels are a diverse family of signaling proteins that mediate rapid electrical signaling events. Among these, voltage-gated potassium or Kv channels are the most diverse partly due to the large number of principal (or α) subunits and auxiliary subunits that can assemble in different combinations to generate Kv channel complexes with distinct structures and functions. The diversity of Kv channels underlies much of the variability in the active properties between different mammalian central neurons and the dynamic changes that lead to experience-dependent plasticity in intrinsic excitability. Recent studies have revealed that Kv channel α subunits and auxiliary subunits are extensively phosphorylated, contributing to additional structural and functional diversity. Here, we highlight recent studies that show that auxiliary subunits exert some of their profound effects on dendritic Kv4 and axonal Kv1 channels through phosphorylation-dependent mechanisms, either due to phosphorylation on the auxiliary subunit itself or by influencing the extent and/or impact of α subunit phosphorylation. The complex effects of auxiliary subunits and phosphorylation provide a potent mechanism to generate additional diversity in the structure and function of Kv4 and Kv1 channels, as well as allowing for dynamic reversible regulation of these important ion channels. © 2011 Springer-Verlag.

Leimkuhler S.,University of Potsdam | Iobbi-Nivol C.,Aix - Marseille University
FEMS Microbiology Reviews | Year: 2015

Molybdoenzymes are widespread in eukaryotic and prokaryotic organisms where they play crucial functions in detoxification reactions in the metabolism of humans and bacteria, in nitrate assimilation in plants and in anaerobic respiration in bacteria. To be fully active, these enzymes require complex molybdenum-containing cofactors, which are inserted into the apoenzymes after folding. For almost all the bacterial molybdoenzymes, molybdenum cofactor insertion requires the involvement of specific chaperones. In this review, an overview on the molybdenum cofactor biosynthetic pathway is given together with the role of specific chaperones dedicated for molybdenum cofactor insertion and maturation. Many bacteria are involved in geochemical cycles on earth and therefore have an environmental impact. The roles of molybdoenzymes in bioremediation and for environmental applications are presented. © FEMS 2015.

Leloup L.,Aix - Marseille University | Wells A.,University of Pittsburgh
Expert Opinion on Therapeutic Targets | Year: 2011

Introduction: The intracellular signaling cysteine proteases, calpains (specifically the ubiquitous calpains 1 and 2), are involved in numerous physiological and pathological phenomena. Several works have highlighted the implication of calpains in processes crucial for cancer development and progression. For these reasons, calpains are considered by several authors as potential anti-cancer targets. Areas covered: How calpains are implicated in cancer formation and development, how these enzymes are deregulated in cancer cells and how these proteases could be targeted by anti-cancer drugs. Studies published in the last 10 years are focused on. Expert opinion: Targeting calpain activity with specific inhibitors could be a novel approach to limiting development of primary tumors and formation of metastases, by inhibiting tumor cell migration and invasion, which allows dissemination as well as tumor neovascularization, which in turn allows expansion. However, such drugs could interfere with anti-cancer treatments, as ubiquitous calpains play crucial roles in chemotherapy-induced apoptosis. For these reasons, drugs targeting calpains would have to be used selectively to avoid interference with other treatments and physiological processes. Further studies will be required concerning the other members of the calpain family and their potential implication in cancer development before considering treatments targeting their activity. © 2011 Informa UK, Ltd.

Pinot F.,University of Strasbourg | Beisson F.,Aix - Marseille University
FEBS Journal | Year: 2011

In plants, fatty acids (FA) are subjected to various types of oxygenation reactions. Products include hydroxyacids, as well as hydroperoxides, epoxides, aldehydes, ketones and α,ω-diacids. Many of these reactions are catalysed by cytochrome P450s (P450s), which represent one of the largest superfamilies of proteins in plants. The existence of P450-type metabolizing FA enzymes in plants was established approximately four decades ago in studies on the biosynthesis of lipid polyesters. Biochemical investigations have highlighted two major characteristics of P450s acting on FAs: (a) they can be inhibited by FA analogues carrying an acetylenic function, and (b) they can be enhanced by biotic and abiotic stress at the transcriptional level. Based on these properties, P450s capable of producing oxidized FA have been identified and characterized from various plant species. Until recently, the vast majority of characterized P450s acting on FAs belonged to the CYP86 and CYP94 families. In the past five years, rapid progress in the characterization of mutants in the model plant Arabidopsis thaliana has allowed the identification of such enzymes in many other P450 families (i.e. CYP703, CYP704, CYP709, CYP77, CYP74). The presence in a single species of distinct enzymes characterized by their own regulation and catalytic properties raised the question of their physiological meaning. Functional studies in A. thaliana have demonstrated the involvement of FA hydroxylases in the synthesis of the protective biopolymers cutin, suberin and sporopollenin. In addition, several lines of evidence discussed in this minireview are consistent with P450s metabolizing FAs in many aspects of plant biology, such as defence against pathogens and herbivores, development, catabolism or reproduction. © 2010 FEBS.

Sacco E.,University of Cassino and Southern Lazio | Lebon F.,Aix - Marseille University
International Journal of Solids and Structures | Year: 2012

The present paper deals with a micromechanical model of interface able to couple the damage (micro-crack) evolution, the non-penetration conditions (Signorini equations) and the friction effect (Coulomb's law). At a typical point of the interface, a representative volume element (RVE) is considered; it is characterized by the presence of two different materials and by a microcrack evolving along the material discontinuity. An innovative deductive approach based on a micromechanical analysis and on a homogenization procedure is proposed. In particular, the solution of the micromechanical problem on the RVE is determined considering three subproblems and properly superimposing their solutions. Then, a simplified approach is proposed by modeling the behavior of the material constituting the RVE in a very essential manner. Evolutionary laws for the crack growth are given and the equations governing the unilateral and friction phenomena are presented. The original proposed procedure is applied to derive an interface model for masonry structures considering the brick-mortar interaction. The solutions of three subproblems are determined adopting the finite element method on the specific RVE for different crack lengths; then, the solutions are interpolated by adopting a spline technique and properly superimposed. A numerical procedure based on the return-mapping algorithm and the classical backward-Euler integration scheme is presented for the specific considered evolutive problem. Some numerical tests, for monotonic and cyclic loadings are presented, remarking the ability of the proposed approach to reproduce the complex features of brick-mortar interfaces; comparisons between the results obtained adopting the original proposed model and the simplified model are performed. © 2012 Elsevier Ltd. All rights reserved.

Bailly R.,Aix - Marseille University
Journal of Machine Learning Research | Year: 2011

In this paper, we address the problem of non-parametric density estimation on a set of strings ∑*. We introduce a probabilistic model - called quadratic weighted automaton, or QWA - and we present some methods which can be used in a density estimation task. A spectral analysis method leads to an effective regularization and a consistent estimate of the parameters. We provide a set of theoretical results on the convergence of this method. Experiments show that the combination of this method with likelihood maximization may be an interesting alternative to the well-known Baum-Welch algorithm. © 2011 R. BAILLY.

Anthony E.J.,Aix - Marseille University | Gratiot N.,Grenoble Institute of Technology
Ecological Engineering | Year: 2012

This short communication highlights potential destabilisation of the muddy coast of Guyana, South America, caused by large-scale mangrove destruction. The stability of the coast of Guyana, which is part of one of the world's most extensive mangrove coasts, depends on large mud banks migrating alongshore from the mouth of the Amazon River and on mangrove colonisation of these banks. Under the pressures of economic development, the coastal zone of Guyana is progressively being transformed into agricultural land and aquaculture estates, protected by coastal dikes. These hard coastal defence structures, constructed in recent years, are less effective in dissipating wave energy than mud banks. They also hinder the various processes involved in the consolidation and subsequent mangrove colonisation of these banks, notably by enclosing mature mangrove forests and preventing propagule transport from these forests to mud banks. If unchecked, the progressive breakdown in the mud-bank and associated mangrove system that has led to progradation of the coastal plain of Guyana over the last 5000 years will result in large-scale coastal erosion that can only be countered by further engineering structures at prohibitive costs. The only coastal defence strategy, sound and viable over the long term, with regards to both environmental conservation and cost, consists in restoring a dynamic mud-bank and mangrove system on this wave-exposed coast. © 2012 Elsevier B.V.

Weber A.A.-T.,University of Geneva | Weber A.A.-T.,Aix - Marseille University | Pawlowski J.,University of Geneva
PLoS ONE | Year: 2013

Protists are key players in microbial communities, yet our understanding of their role in ecosystem functioning is seriously impeded by difficulties in identification of protistan species and their quantification. Current microscopy-based methods used for determining the abundance of protists are tedious and often show a low taxonomic resolution. Recent development of next-generation sequencing technologies offered a very powerful tool for studying the richness of protistan communities. Still, the relationship between abundance of species and number of sequences remains subjected to various technical and biological biases. Here, we test the impact of some of these biological biases on sequence abundance of SSU rRNA gene in foraminifera. First, we quantified the rDNA copy number and rRNA expression level of three species of foraminifera by qPCR. Then, we prepared five mock communities with these species, two in equal proportions and three with one species ten times more abundant. The libraries of rDNA and cDNA of the mock communities were constructed, Sanger sequenced and the sequence abundance was calculated. The initial species proportions were compared to the raw sequence proportions as well as to the sequence abundance normalized by rDNA copy number and rRNA expression level per species. Our results showed that without normalization, all sequence data differed significantly from the initial proportions. After normalization, the congruence between the number of sequences and number of specimens was much better. We conclude that without normalization, species abundance determination based on sequence data was not possible because of the effect of biological biases. Nevertheless, by taking into account the variation of rDNA copy number and rRNA expression level we were able to infer species abundance, suggesting that our approach can be successful in controlled conditions. © 2013 Weber, Pawlowski.

Raoult D.,Aix - Marseille University
Intervirology | Year: 2013

Microbes were defined in the 19th century by L. Pasteur. Prokaryotes and eukaryotes, which are divided into two worlds of microbes, were introduced by E. Chatton in 1925. R. Woese divided this world into three domains based on ribosomal analysis (Bacteria, Archaea, and Eukarya). The discovery of Mimivirus and other Megavirales, that are microbes, led to divide the microbiological world into four branches. I introduced the name TRUC (Things Resisting Uncompleted Classifications) to accommodate the division in four of the currently known microbiological world. © 2013 S. Karger AG, Basel.

Pieri M.M.,University of Portsmouth | Pieri M.M.,Aix - Marseille University
Monthly Notices of the Royal Astronomical Society: Letters | Year: 2014

In light of recent successes in measuring baryon acoustic oscillations (BAO) in quasar absorption using the Lyman α (Lyα) transition, I explore the possibility of using the 1548 Å transition of triply ionized carbon (C IV) as a tracer. While the Lyα forest is a more sensitive tracer of intergalactic gas, it is limited by the fact that it can only be measured in the optical window at redshifts z > 2. Quasars are challenging to identify and observe at these high redshifts, but the C IV forest can be probed down to redshifts z ≈ 1.3, taking full advantage of the peak in the redshift distribution of quasars that can be targeted with high efficiency. I explore the strength of the C IV absorption signal and show that the absorbing population on the red side of the Lyα emission line is dominated by C IV (and so will dominate over the potential BAO signal of other metals). As a consequence, I argue that forthcoming surveys may have a sufficient increase in quasar number density to offset the lower sensitivity of the C IV forest and provide competitive precision using both the C IV autocorrelation and the C IV-quasar cross-correlation at (z) ≈ 1.6. © 2014 The Authors.

Herrerias M.J.,University of Nottingham | Joyeux R.,Macquarie University | Girardin E.,Aix - Marseille University
Applied Energy | Year: 2013

The relationship between energy consumption and economic growth has created a large body of research in the energy-economics literature. In this paper, we investigate such a relation in the case of Chinese regions from 1995 to 2009. The majority of previous studies have ignored the regional dimension and the cross-sectional dependence of provinces. Besides, different energy policies adopted by the government have influenced energy intensity over time, showing improvement in the 1990s and deterioration from 2000 onwards. Thus, it is necessary to examine these two periods separately. Moreover, a detailed disaggregation of total energy consumption into electricity, coal, coke, and crude oil consumption and its linkage with economic growth may provide new insights for the design of energy policy across Chinese regions. We use panel techniques to test the direction of the causality in the long- and short-run between these different types of energy consumption and economic growth. Our results are mixed from 1995 to 2009 due the aforementioned break around 1999. However, in all cases our estimations provide empirical evidence that from 1999 to 2009 there is unidirectional causation from economic growth to energy consumption in the long-run. Therefore, energy-saving policies can be adopted without interrupting the path of growth. © 2013 Elsevier Ltd.

The primary function assigned to the sodiumdependent glutamate transporters, also known as excitatory amino acid transporters (EAATs), is to maintain the extracellular glutamate concentration in the low micromolar range, allowing glutamate to be used as a signaling molecule in the brain and preventing its cytotoxic effects. However, glutamate and cyst(e)ine, that is also a substrate of EAATs, are also important metabolites used for instance in the synthesis of the main antioxidant glutathione. This review describes the evidence suggesting that EAATs, by providing glutathione precursors, are crucial to prevent oxidative death in particular cells of the nervous system while being dispensable in others. This differential importance may depend on the way antioxidant defenses are maintained in each cell type and on the metabolic fate of transported substrates, both being probably controlled by EAAT interacting proteins. As oxidative stress invariably contributes to various forms of cell death, a better understanding of how antioxidant defenses are maintained in particular brain cells will probably help to develop protective strategies in degenerative insults specifically affecting these cells. © Springer-Verlag 2011.

Cossart R.,Aix - Marseille University
Current Opinion in Neurobiology | Year: 2014

GABAergic microcircuits structure the activation of neuronal ensembles that support most cortical computations. Because of the heterogeneous nature of the GABAergic cell community, a full understanding of structure-function relationships in these microcircuits may be hampered by a reductionist approach that consists of classifying them according to an exhaustive collection of parameters. It therefore could be beneficial to our understanding of these complex cells to also consider other approaches. Thus, graph theory has recently taught us that biological networks often include hub nodes that are essential for information flow, and ensuing experimental evidence has demonstrated the existence of 'operational' hub neurons. So far, only GABAergic neurons have been identified as 'operational hubs', further emphasizing their critical function in controlling cortical network dynamics. © 2013.

Recent literature reviews showed that overweight and obesity represent a major health threat in adults with intellectual disability (ID). However, the current evidence around the prevalence and risk factors associated with overweight and obesity in children and adolescents with ID remains unclear. The objective of this article was thus to review the available English- and French-language studies examining the prevalence and risk factors associated with overweight and obesity in youths with ID. Ten studies providing original data on this topic were identified and included in this review. Results demonstrated that (i) overweight and obesity represent a significant secondary health problem in youths with ID; and (ii) obesity risk significantly increases with age. Considering all of the limitations of the reviewed studies (i.e. heterogeneity in sample size and in overweight and obesity classification criteria; lack of comparison group; restrictive number of risk factors examined, etc.), these findings remain preliminary and highlight the need for future research in this area. © 2010 The Authors obesity reviews © 2010 International Association for the Study of Obesity.

Millot V.,University Paris Diderot | Sire Y.,Aix - Marseille University
Archive for Rational Mechanics and Analysis | Year: 2014

This paper is devoted to the asymptotic analysis of a fractional version of the Ginzburg–Landau equation in bounded domains, where the Laplacian is replaced by an integro-differential operator related to the square root Laplacian as defined in Fourier space. In the singular limit (Formula presented). , we show that solutions with uniformly bounded energy converge weakly to sphere valued 1/2-harmonic maps, that is, the fractional analogues of the usual harmonic maps. In addition, the convergence holds in smooth functions spaces away from a countably (Formula presented). -rectifiable closed set of finite (n−1)-Hausdorff measure. The proof relies on the representation of the square root Laplacian as a Dirichlet-to-Neumann operator in one more dimension, and on the analysis of a boundary version of the Ginzburg–Landau equation. Besides the analysis of the fractional Ginzburg–Landau equation, we also give a general partial regularity result for stationary 1/2-harmonic maps in an arbitrary dimension. © 2014, Springer-Verlag Berlin Heidelberg.

Chemla S.,French Institute for Research in Computer Science and Automation | Chavane F.,Aix - Marseille University
Journal of Physiology Paris | Year: 2010

In this review, we present the voltage-sensitive dye imaging (VSDI) method. The possibility offered for in vivo (and in vitro) brain imaging is unprecedented in terms of spatial and temporal resolution. However, the unresolved multi-component origin of the optical signal encourages us to perform a detailed analysis of the method limitation and the existing models. We propose a biophysical model at a mesoscopic scale in order to understand and interpret this signal. © 2009 Elsevier Ltd. All rights reserved.

Schaeffer N.,Aix - Marseille University | Le Dizes S.,Joseph Fourier University
Journal of Fluid Mechanics | Year: 2010

In this paper, we analyse by numerical simulations the nonlinear dynamics of the elliptic instability in the configurations of a single strained vortex and a system of two counter-rotating vortices. We show that although a weakly nonlinear regime associated with a limit cycle is possible, the nonlinear evolution far from the instability threshold is, in general, much more catastrophic for the vortex. In both configurations, we put forward some evidence of a universal nonlinear transition involving shear layer formation and vortex loop ejection, leading to a strong alteration and attenuation of the vortex, and a rapid growth of the vortex core size. Copyright © Cambridge University Press 2010.

Dolocan V.O.,Aix - Marseille University
Applied Physics Letters | Year: 2014

Interactions between pairs of magnetic domain walls (DW) and pinning by radial constrictions were studied in cylindrical nanowires with surface roughness. It was found that a radial constriction creates a symmetric pinning potential well, with a change of slope when the DW is situated outside the notch. Surface deformation induces an asymmetry in the pinning potential as well as dynamical pinning. The depinning fields of the domain walls were found generally to decrease with increasing surface roughness. A DW pinned at a radial constriction creates a pinning potential well for a free DW in a parallel wire. We determined that trapped bound DW states appear above the depinning threshold and that the surface roughness facilitates the trapped bound DW states in parallel wires. © 2014 AIP Publishing LLC.

Ben-Ari Y.,Aix - Marseille University
Nature Reviews Neuroscience | Year: 2015

Birth is associated with a neuroprotective, oxytocin-mediated abrupt excitatory-to-inhibitory GABA shift that is abolished in autism, and its restoration attenuates the disorder in offspring. In this Opinion article, I discuss the links between birth-related stressful mechanisms, persistent excitatory GABA actions, perturbed network oscillations and autism. I propose that birth (parturition) is a critical period that confirms, attenuates or aggravates the deleterious effects of intrauterine genetic or environmental insults. © 2015 Macmillan Publishers Limited. All rights reserved.

Charles L.,Aix - Marseille University
Mass Spectrometry Reviews | Year: 2014

Mass spectrometry is increasingly used in the field of synthetic polymers as a fast and accurate technique for end-group analysis. More particularly, matrix-assisted laser desorption/ ionization (MALDI) has gained much popularity because it allows quite simple mass spectra to be obtained, displaying a single distribution for each polymeric species present in the sample, in contrast to electrospray ionization (ESI) which readily promotes multiple charging for most polymers. A soft ionization process, ensuring the integrity of the species upon transfer into gas phase ions, is however mandatory for polymer end-group analysis since information about the chain terminations mainly rely on the m/z values measured for polymer adducts. As compared to ESI, MALDI is sometimes suspected to be a quite "hard" ionization technique, leading to spontaneous dissociation of ionized species either in the source or during their flight time. This issue is of particular concern for polymers carrying so-called fragile end-groups arising from their mode of synthesis. In particular, controlled radical polymerization (CRP) processes, one of the most important advances in the field of polymer science during the last 20 years, allow the production of polymers with well-defined molecular distribution and low polydispersities, but they are all based on the low dissociation energy of the chemical bond between the last monomer and the terminating group. As a result, if macromolecules are activated while being ionized, this end-group is prone to fragmentation and ions measured in the mass spectra do no longer reflect the original chain composition. However, different results are reported in the literature about the ability of MALDI to generate intact ions from CRP synthetic polymers. This article reviews MALDI MS data reported for synthetic polymers produced by atom transfer radical polymerization (ATRP), reversible addition- fragmentation transfer polymerization (RAFT), and nitroxide- mediated polymerization (NMP), the three most studied CRP techniques. The general principle of each polymerization process, which defines the structure of the end-groups in both targeted macromolecules and species arising from eventual side-reactions, is first briefly presented. An overview of MALDI data reported for samples obtained upon polymerization of different monomers are then commented for each polymerization techniques with regards to the success of the ionization method to generate intact cationic adducts and its propensity to distinguish in-source fragments from polymerization sideproducts. © 2013 by Wiley Periodicals, Inc.

Most glutamatergic synapses in the mammalian central nervous system are covered by thin astroglial processes that exert a dual action on synaptically released glutamate: they form physical barriers that oppose diffusion and they carry specific transporters that remove glutamate from the extracellular space. The present study was undertaken to investigate the dual action of glia by means of computer simulation. A realistic synapse model based on electron microscope data and Monte Carlo algorithms were used for this purpose. Results show (1) that physical obstacles formed by glial processes delay glutamate exit from the cleft and (2) that this effect is efficiently counteracted by glutamate uptake. Thus, depending on transporter densities, the presence of perisynaptic glia may result in increased or decreased glutamate transient in the synaptic cleft. Changes in temporal profiles of cleft glutamate concentration induced by glia differentially impact the response of the various synaptic and perisynaptic receptor subtypes. In particular, GluN2B- and GluN2C-NMDA receptor responses are strongly modified while GluN2A-NMDA receptor responses are almost unaffected. Thus, variations in glial transporter expression may allow differential tuning of NMDA receptors according to their subunit composition. In addition, simulation data suggest that the sink effect generated by transporters accumulation in the vicinity of the release site is the main mechanism limiting glutamate spill-out. Physical obstacles formed by glial processes play a comparatively minor role. © 2013 Jean-Pierre Kessler.

Donner J.S.,ICFO - Institute of Photonic Sciences | Thompson S.A.,ICFO - Institute of Photonic Sciences | Kreuzer M.P.,ICFO - Institute of Photonic Sciences | Baffou G.,Aix - Marseille University | And 2 more authors.
Nano Letters | Year: 2012

Heat is of fundamental importance in many cellular processes such as cell metabolism, cell division and gene expression.(1-3) Accurate and noninvasive monitoring of temperature changes in individual cells could thus help clarify intricate cellular processes and develop new applications in biology and medicine. Here we report the use of green fluorescent proteins (GFP) as thermal nanoprobes suited for intracellular temperature mapping. Temperature probing is achieved by monitoring the fluorescence polarization anisotropy of GFP. The method is tested on GFP-transfected HeLa and U-87 MG cancer cell lines where we monitored the heat delivery by photothermal heating of gold nanorods surrounding the cells. A spatial resolution of 300 nm and a temperature accuracy of about 0.4 °C are achieved. Benefiting from its full compatibility with widely used GFP-transfected cells, this approach provides a noninvasive tool for fundamental and applied research in areas ranging from molecular biology to therapeutic and diagnostic studies. © 2012 American Chemical Society.

Deleuil T.,Aix - Marseille University
Review of European Community and International Environmental Law | Year: 2012

The common but differentiated responsibilities (CBDR) principle has played a major part in the post-2012 climate change negotiations. However, the rise of emerging economies and the multiplication of State categories have called the initial compromise under the United Nations Framework Convention on Climate Change (UNFCCC) into question and, until now, no balance between the conflicting claims of States has been found. Meanwhile, the principle is still not fixed in terms of its formulation, legal nature and practice. Although it enabled agreement on the UNFCCC in the 1990s, the principle has also contributed to climate negotiation deadlocks. As a result, it appears to be fading in the 2011 Durban decisions, giving place to general contextual norms. Moreover, the decision on the Durban Platform, through which the post-2020 negotiations will take place, does not refer to the principle at all. Still, it is clear that differential treatment will have a structuring role in the post-2020 negotiations. This article examines the Durban outcomes in the light of the CBDR principle, with a view to analyzing the prospects of differential treatment in international climate change law. © 2012 Blackwell Publishing Ltd.

De Padova P.,National Research Council Italy | Kubo O.,Japan International Center for Materials Nanoarchitectonics | Olivieri B.,National Research Council Italy | Quaresima C.,National Research Council Italy | And 4 more authors.
Nano Letters | Year: 2012

The synthesis of silicene, graphene-like silicon, has generated very strong interest. Here, we reveal the growth of high aspect ratio, perfectly straight, and aligned silicon nanoribbons, exhibiting pyramidal cross section. They are multistacks of silicene and show in angle-resolved photoemission cone-like dispersion of their φ and φ* bands, at the X̄ point of their one-dimensional Brillouin zone, with Fermi velocity of ∼1.3 × 10 6 m sec-1, which is very promising for potential applications. © 2012 American Chemical Society.

Fantini J.,Aix - Marseille University | Barrantes F.J.,CONICET
Frontiers in Physiology | Year: 2013

The plasma membrane of eukaryotic cells contains several types of lipids displaying high biochemical variability in both their apolar moiety (e.g., the acyl chain of glycerolipids) and their polar head (e.g., the sugar structure of glycosphingolipids). Among these lipids, cholesterol is unique because its biochemical variability is almost exclusively restricted to the oxidation of its polar -OH group. Although generally considered the most rigid membrane lipid, cholesterol can adopt a broad range of conformations due to the flexibility of its isooctyl chain linked to the polycyclic sterane backbone. Moreover, cholesterol is an asymmetric molecule displaying a planar α face and a rough β face. Overall, these structural features open up a number of possible interactions between cholesterol and membrane lipids and proteins, consistent with the prominent regulatory functions that this unique lipid exerts on membrane components. The aim of this review is to describe how cholesterol interacts with membrane lipids and proteins at the molecular/atomic scale, with special emphasis on transmembrane domains of proteins containing either the consensus cholesterol-binding motifs CRAC and CARC or a tilted peptide. Despite their broad structural diversity, all these domains bind cholesterol through common molecular mechanisms, leading to the identification of a subset of amino acid residues that are overrepresented in both linear and three-dimensional membrane cholesterol-binding sites.

Thibaudau F.,Aix - Marseille University | Thibaudau F.,CNRS Interdisciplinary Center on Nanoscience in Marseille
Journal of Physical Chemistry Letters | Year: 2012

We report results on ultrafast photothermal release of DNA from gold nanoparticles. We show that dehybridization of oligonucleotide duplex anchored on a gold nanoparticle surface occurs during a single laser pulse, leading to the release of single-strand DNA in solution. Breaking of the Au-S bond anchoring the duplex and the release of thiolated DNA are also evidenced. Our findings show that the size distribution of the nanoparticles plays a major role in the control of both phenomena. We establish a criterion regarding the size distribution of nanoparticles that allows full release of DNA without breaking of the anchoring thiol bonds. © 2012 American Chemical Society.

Knauth P.,Aix - Marseille University | Di Vona M.L.,University of Rome Tor Vergata
Solid State Ionics | Year: 2012

Recent progress on proton-conducting Sulfonated Aromatic Polymers is reviewed, including composite and cross-linked ionomers. Proton conductivity and water uptake, studied as function of relative humidity, can be combined to calculate the effective proton mobility in ionomers. The plot of proton mobility versus proton concentration shows common features for various ionomers, which can be related to percolation and tortuosity of hydrated nanometric channels. Proton conductivity can even be enhanced in cross-linked ionomers, possibly due to a reduction of channel tortuosity. © 2012 Elsevier B.V.

De Bentzmann S.,Aix - Marseille University | Plesiat P.,Laboratoire Of Bacteriologie
Environmental Microbiology | Year: 2011

Pseudomonas aeruginosa, a Gram-negative environmental species and an opportunistic microorganism, establishes itself in vulnerable patients, such as those with cystic fibrosis or hospitalized in intensive care units. It has become a major cause of nosocomial infections worldwide (about 10% of all such infections in most European Union hospitals) and a serious threat to Public Health. The overuse and misuse of antibiotics have also led to the selection of resistant strains against which very few therapeutic options exist. How an environmental species can cause human infections remains a key question that still needs elucidation despite the incredibly high progress that has been made in the P. aeruginosa biology over the past decades. The workshop belonging to Current trends in Biomedicine series, which was held under the sponsorship of the Universidad International de Andalucia between the 8th and the 10th November 2010 brought in the most recent advances in the environmental life of P. aeruginosa, the human P. aeruginosa infections, the new animal models to study Pseudomonas infections, the new genetic aspects including metabolomics, genomics and bioinformatics and the community lifestyle named biofilm that accounts for P. aeruginosa persistence in humans. This workshop organized by Soeren Molin (Danemark), Juan-Luis Ramos (Spain) and Sophie de Bentzmann (France) gathered 46 researchers coming from 11 European and American countries in a small format and was hosted in the 'Sede Antonio Machado' in Baeza. It was organized in seven sessions covering animal models for P. aeruginosa pathogenesis, resistance to drugs, regulatory potency including small RNA, two component systems, extracytoplasmic function sigma factors and trancriptional regulators, new therapies emerging from dissection of molecular mechanisms, and evolutionary mechanisms of P. aeruginosa strains in patients. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

Piccoli B.,Rutgers University | Rossi F.,Aix - Marseille University
Archive for Rational Mechanics and Analysis | Year: 2014

In this article, we generalize the Wasserstein distance to measures with different masses. We study the properties of this distance. In particular, we show that it metrizes weak convergence for tight sequences. We use this generalized Wasserstein distance to study a transport equation with a source, in which both the vector field and the source depend on the measure itself. We prove the existence and uniqueness of the solution to the Cauchy problem when the vector field and the source are Lipschitzian with respect to the generalized Wasserstein distance. © 2013 Springer-Verlag Berlin Heidelberg.

Timsit Y.,Aix - Marseille University
Molecules | Year: 2012

Strand separation is a fundamental molecular process essential for the reading of the genetic information during DNA replication, transcription and recombination. However, DNA melting in physiological conditions in which the double helix is expected to be stable represents a challenging problem. Current models propose that negative supercoiling destabilizes the double helix and promotes the spontaneous, sequence-dependent DNA melting. The present review examines an alternative view and reveals how DNA compaction may trigger the sequence dependent opening of the base pairs. This analysis shows that in DNA crystals, tight DNA-DNA interactions destabilize the double helices at various degrees, from the alteration of the base-stacking to the opening of the base-pairs. The electrostatic repulsion generated by the DNA close approach of the negatively charged sugar phosphate backbones may therefore provide a potential source of the energy required for DNA melting. These observations suggest a new molecular mechanism for the initial steps of strand separation in which the coupling of the DNA tertiary and secondary interactions both actively triggers the base pair opening and stabilizes the intermediate states during the melting pathway. © 2012 by the authors; licensee MDPI, Basel, Switzerland.

Di Piazza A.,Aix - Marseille University
Geographical Research | Year: 2014

This paper presents a new geometry of the western Pacific based on an analysis of the time necessary for canoes to sail to islands around Samoa. Using methods proposed by Francis Galton in 1866 and 1881, updated by a computer simulation of sailing trajectories, the author demonstrates the existence of a navigational threshold east of Samoa through systematic 'displacement' of islands according to sailing time in winter and summer - a threshold that helps explain the ca 2000 year pause between the Lapita era settlement of Melanesia-West Polynesia and the settlement of East Polynesia. © 2013 Institute of Australian Geographers.

Herve G.,SNPE | Roussel C.,Aix - Marseille University | Graindorge H.,SNPE
Angewandte Chemie - International Edition | Year: 2010

(Figure Presented) Lowering the boom: 3,4,5-trinitro-1H-pyr-azole (TNP, see picture) has been prepared by the unexpected nitration of 3,5dinitropyrazole with a super-electrophile generated from 20-30% sulfuric oleum mixed with nitric acid. The remarkable stability of TNP results from the preservation of the ring geometry and the specific conformation of the nitro group at C4 which confers low acidity on the material. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.

Bonami P.,Aix - Marseille University
Mathematical Programming Computation | Year: 2012

The strengthened lift-and-project closure of a mixed integer linear program is the polyhedron obtained by intersecting all strengthened lift-and-project cuts obtained from its initial formulation, or equivalently all mixed integer Gomory cuts read from all tableaux corresponding to feasible and infeasible bases of the LP relaxation. In this paper, we present an algorithm for approximately optimizing over the strengthened lift-and-project closure. The originality of our method is that it relies on a cut generation linear programming problem which is obtained from the original LP relaxation by only modifying the bounds on the variables and constraints. This separation LP can also be seen as dual to the cut generation LP used in disjunctive programming procedures with a particular normalization. We study properties of this separation LP, and discuss how to use it to approximately optimize over the strengthened lift-and-project closure. Finally, we present computational experiments and comparisons with recent related works. © 2012 Springer and Mathematical Optimization Society.

Chepoi V.,Aix - Marseille University
SIAM Journal on Computing | Year: 2012

In this paper, we present a counterexample to a conjecture of Rozoy and Thiagarajan from 1991 (also called the nice labeling problem) asserting that any (coherent) event structure with finite degree admits a labeling with a finite number of labels or, equivalently, that there exists a function f: ℕ → ℕ such that an event structure with degree ≤ n admits a labeling with at most f(n) labels. Our counterexample is based on Burling's construction from 1965 of 3-dimensional box hypergraphs with clique number 2 and arbitrarily large chromatic numbers and the bijection between domains of event structures and median graphs established by Barthélemy and Constantin in 1993. © by SIAM. Unauthorized reproduction of this article is prohibited.

Douzi B.,CNRS Optic of Semiconductor nanoStructures Group | Douzi B.,Aix - Marseille University | Filloux A.,Imperial College London | Voulhoux R.,CNRS Optic of Semiconductor nanoStructures Group
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2012

Gram-negative bacteria have evolved several secretory pathways to release enzymes or toxins into the surrounding environment or into the target cells. The type II secretion system (T2SS) is conserved in Gram-negative bacteria and involves a set of 12 to 16 different proteins. Components of the T2SS are located in both the inner and outer membranes where they assemble into a supra-molecular complex spanning the bacterial envelope, also called the secreton. The T2SS substrates transiently go through the periplasm before they are translocated across the outer membrane and exposed to the extracellular milieu. The T2SS is unique in its ability to promote secretion of large and sometimes multimeric proteins that are folded in the periplasm. The present review describes recently identified protein-protein interactions together with structural and functional advances in the field that have contributed to improve our understanding on how the type II secretion apparatus assembles and on the role played by individual proteins of this highly sophisticated system. © 2012 The Royal Society.

Mycotoxins are fungal secondary metabolites contaminating food and causing toxicity to animals and humans. Among the various mycotoxins found in crops used for food and feed production, the trichothecene toxin deoxynivalenol (DON or vomitoxin) is one of the most prevalent and hazardous. In addition to native toxins, food also contains a large amount of plant and fungal derivatives of DON, including acetyl-DON (3 and 15ADON), glucoside-DON (D3G), and potentially animal derivatives such as glucuronide metabolites (D3 and D15GA) present in animal tissues (e.g., blood, muscle and liver tissue). The present review summarizes previous and very recent experimental data collected in vivo and in vitro regarding the transport, detoxification/metabolism and physiological impact of DON and its derivatives on intestinal, immune, endocrine and neurologic functions during their journey from the gut to the brain. © 2013 by the authors; licensee MDPI, Basel, Switzerland.

Objectives: The gender identity disorder (GID), such as defined by the DSM, is usually used by French psychiatrists to take care of trans people in specialized hospital teams. The paper questions this diagnostic process in a context where the GID is object of debates and controversies and where the pathological characterization of the transgender experience is questioned. Methods: From an ethnographic fieldwork conducted between 2005 and 2008 in a French hospital, the paper focuses on the use of GID in the psychiatric consultation, trying to show what it imposes and proposes both to doctors and consultants. First of all, it is suggested that the term autodiagnosis should not be used to define consultants' discourse but to hold on to what they said precisely in the first consultation. Results: Three modes of declaration have been found: declarations of identity, declarations of situation and declarations of intent. This paper shows how they are put to test in the psychiatric investigation. Discussion: In this diagnosis process, the gender identity is seen as subjective but in a version of mental interiority in conformity with the classic western version of gender identity that sees gender as a property of the person. Conclusion: This way of taking care is not as productive as psychiatrists imagine it is. If most of them are attached to the diagnosis of GID, it is because they see it as the only way to protect against an inappropriate transitioning. Nevertheless, it is not sure whether it is the diagnosis, which can do this as the conclusion of this paper suggests. © 2015 Elsevier Masson SAS.

Pellissier H.,Aix - Marseille University
Chemical Reviews | Year: 2013

Domino reactions are classified according to the mechanism of the individual steps, which may be of the same or different type. The quality and importance of a domino reaction can be correlated to the number of bonds generated in such a process and the increase in complexity. The concept of domino sequences has allowed easily reaching high molecular complexity with very often excellent levels of stereocontrol with simple operational procedures, as well as advantages of savings in solvent, time, energy, and costs. The use of one-component, two-component, and multicomponent domino reactions in asymmetric synthesis is increasing constantly. Such single-step reactions allow the synthesis of a wide range of structurally diverse and complex chiral molecules from simple substrates in an economically favorable manner by avoiding the use of costly and time-consuming protection deprotection processes, as well as purification procedures of intermediates.

Santhanam P.,Marshall University | Taieb D.,Aix - Marseille University
Clinical Endocrinology | Year: 2014

18F-FDOPA (6-[18F]-L-fluoro-L-3, 4-dihydroxyphenylalanine)-based PET/CT imaging can be a useful tool for the detection of different neuroendocrine tumours (NETs). 18F-FDOPA is taken up into the cells via the neutral amino acid transporter (LAT1/4F2hc). This transporter is also coupled to the mammalian target of rapamycin (mTOR) signalling pathway. 18F-FDOPA PET/CT may be performed for confirmation of diagnosis of pheochromocytoma/paraganglioma, staging at initial presentation, restaging and follow-up of patients. In SDHx-related syndromes, 18F-FDG PET/CT should be performed in addition to 18F-FDOPA PET/CT. 18F-FDOPA PET/CT is also invaluable in the detection staging/restaging of carcinoid tumours and has greater sensitivity as compared to somatostatin receptor scintigraphy. 18F-FDOPA PET/CT can also distinguish between focal vs diffuse CHI. It is not as useful in adult hyperinsulinism due to increased background uptake, but the problem may be overcome with the help of premedication with carbidopa. It has limited use in pancreatic NETs. 18F-FDOPA PET/CT is a good modality for detection of persistent and residual medullary thyroid cancer (MTC), but 18F-FDG PET/CT may be needed in aggressive tumours. In summary, F-DOPA PET/CT has widespread utility in the diagnosis of different neuroendocrine tumours. © 2014 John Wiley & Sons Ltd.

Lim J.P.,National University of Singapore | Devaux J.,Aix - Marseille University | Yuki N.,National University of Singapore
Autoimmunity Reviews | Year: 2014

Guillain-Barré syndrome is classified into acute inflammatory demyelinating polyneuropathy and acute motor axonal neuropathy. Whereas autoantibodies to GM1 or GD1a induce the development of acute motor axonal neuropathy, pathogenic autoantibodies have yet to be identified in acute inflammatory demyelinating polyneuropathy and chronic inflammatory demyelinating polyneuropathy. This review highlights the importance of autoantibodies to peripheral nerve proteins in the physiopathology of acute and chronic inflammatory demyelinating polyneuropathies. Moreover, we listed up other potential antigens, which may become helpful biomarkers for acquired, dysimmune demyelinating neuropathies based on their critical functions during myelination and their implications in hereditary demyelinating neuropathies. © 2014 Elsevier B.V.

Wynblatt P.,Carnegie Mellon University | Chatain D.,Aix - Marseille University
Acta Materialia | Year: 2013

Molecular dynamics simulations have been performed to study the interaction between a faceted pore and an anisotropic grain boundary (GB). Nickel was chosen as a convenient model system. In order to establish the equilibrium crystal shape (ECS) of the pore, studies were also conducted on isolated pores. Isolated pores were found to be subject to the nucleation inhibition of equilibration that has been predicted by Rohrer et al. (J Am Ceram Soc 2000;83:214, 2001;84: 2099). This work shows that configurations close to the ECS can be obtained if supersaturation within a pore is artificially increased by adding mobile adatoms to the internal surfaces of the pores. In the case of pores located at GBs, the nucleation energy barriers to facet displacement are not present for facets in contact with the GB at the triple line, but may still persist for facets that have no contact with the GB. This problem can be overcome by approaching the equilibrium shape from different initial configurations. The configuration of the GB in the vicinity of the pore has been found to be essentially planar, indicating that GB puckering in the vicinity of anisotropic pores is not generally necessary. The present calculations show that incompatibilities between misoriented pore facets that meet at the triple line with the GB are easily accommodated by local atomic rearrangements at the disordered region of intersection with the GB. © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Gingras M.,CNRS Interdisciplinary Center on Nanoscience in Marseille | Gingras M.,Aix - Marseille University
Chemical Society Reviews | Year: 2013

Carbohelicenes are a class of fascinating chiral helical molecules which have a rich history in chemistry. Over a period of almost 100 years, chemists have developed many methods to prepare them in a racemic or in a non-racemic form. They also possess a series of interesting chiral, physical, electronic and optical properties. However, their utilization in chemistry or chemistry-related fields has rarely appeared in a detailed and comprehensive review. It is the purpose of this review to collect fundamental applications and functions involving carbohelicenes in various disciplines such as in materials science, in nanoscience, in biological chemistry and in supramolecular chemistry. From the numerous synthetic methodologies reported up to now, carbohelicenes and their derivatives can be tailor-made for a better involvement in several subfields. Among those domains are: nanosciences, chemosensing, liquid crystals, molecular switches, polymers, foldamers, supramolecular materials, molecular recognition, conductive and opto-electronic materials, nonlinear optics, chirality studies and asymmetric synthesis. Helicene chemistry is now at a developmental stage, where sufficient application data are now collected and are extremely useful. They provide many more ideas for setting up the basis for future innovative applications. © 2013 The Royal Society of Chemistry.

Gingras M.,CNRS Interdisciplinary Center on Nanoscience in Marseille | Gingras M.,Aix - Marseille University
Chemical Society Reviews | Year: 2013

Carbohelicenes belong to a class of fascinating, chiral, and helicoidal molecules, which have a rich history in chemistry since the very beginning of the 20th century. A renewed interest in polyaromatic chemistry and new synthetic challenges toward the search for innovative physical, biological, chemical and opto-electronic properties have brought high motivation in this field of studies. Theoretical insights gained from polyaromatic, chiral, conjugated and distorted π-systems are also responsible for this development. Several synthetic avenues were originally reported for making lower helicenes, but for many years, photochemical synthesis has remained a major method for producing small amount of helicenes. High-dilution conditions is still a limiting factor in their synthesis. The fulgurous impact of organometallic chemistry, novel synthetic methods, and recent catalytic systems has promoted the development of helicene chemistry, toward a library of tailor-made and highly functionalized helicene molecules. Helicene chemistry is being considered as an expanding and modern field, leading to several applications in supramolecular chemistry, in nanosciences, in chemical-biology, in polymers and materials science. This first part of a series of three reviews on carbohelicenes will be devoted to a comprehensive report on non-stereoselective reactions and methods for producing helicenes, along with their functionalization. © 2013 The Royal Society of Chemistry.

Regis J.,Aix - Marseille University
Acta neurochirurgica. Supplement | Year: 2013

Radiosurgery is commonly considered to be effective through a destructive physical mechanism acting on neural tissue. However, the results of modern neurophysiological, radiological, and histological studies are providing a basis on which to question this assumption. There are now multiple pieces of evidence pointing to a nonlesional mechanism of the radiosurgical action. It appears that tissue destruction is absent or minimal and in almost all cases insufficient to explain the clinical effects produced. There is a real possibility that radiosurgery induces changes in the functioning of neural tissue by differential effects on various neuronal populations and remodeling the glial environment, leading to modulation of function while preserving basic processing. Hence, the majority of radiosurgical procedures induce the desired biological effect without histological destruction of tissue. These findings may result in a major paradigm shift in the treatment of functional brain disorders.

Aquaron R.R.,Aix - Marseille University
Journal of Inherited Metabolic Disease | Year: 2011

Alkaptonuria (AKU) is an autosomal recessive disorder due to homogentisate 1,2-dioxygenase (HGD) deficiency in the liver and characterized by a triad of signs, according to chronology of appearance: homogentisic aciduria (HGA ) or alkaptonuria, ochronosis then ochronotic arthropathy. This inborn error of metabolism is caused by mutations in the HGD gene. In this work we report observations of 96 AKU French patients from 81 families collected in the literature since 1882 and from our personal contribution since 1986, giving an incidence of the disease of around 1:680,000 (96/64.10 6). As expected for an autosomal recessive disorder the main findings of this study were: a slight predominance of males (51/93, 54,8%) over females (42/93, 45,2%), a strong predominance of sibships with one affected individual (68/81, 84,0%) over sibships with two (11/81, 13.6%) and three(2/81, 2.4%) affected individuals. AKU families are scaterred among the French territory suggesting that most cases occured in non-consanguineous unions. Consanguinity was only found in five families. Other peculiarities of this study were (a) ten of these families have both parents from a foreign geographical origin: Poland(3), Italy(3), Portugal(2), Ukraine(1) and India(1) and four families with only one foreign parent (Algeria, Armenia, Serbia, UK), (b) HGD mutations were found in 23 families, (c) four of theses 96 patients were seen by us respectively 28, 29, 39 and 45 years after their report in the literature and (d) seven patients present cardiac and/or renal complications. © 2011 SSIEM and Springer.

Buat V.,Aix - Marseille University
Earth, Planets and Space | Year: 2013

We want to study dust attenuation at ultraviolet (UV) wavelengths at high redshift, where the UV is redshifted to the observed visible light wavelength range. In particular, we search for a bump at 2175 Â. We use photometric data in the Chandra Deep Field South (CDFS), obtained in intermediate and broad band filters by the MUSYC project, to sample the UV rest-frame of 751 galaxies with 0.95 < z < 2.2. When available, infrared (IR) Herschel/ PACS*data from the GOODS-Herschel project, coupled with Sp/fzer/MIPS measurements, are used to estimate the dust emission and to constrain dust attenuation. The spectral energy distribution of each source is fit using the CIGALE code. The average attenuation curve found for our sample galaxies exhibits a UV bump whose amplitude is similar to that observed in the extinction curve of the LMC super-shell region. The slope of the average attenuation curve at UV wavelength is found steeper than that for local starburst galaxies. The amount of dust attenuation at UV wavelengths is found to increase with stellar mass and to decrease as UV luminosity increases. © The Society of Geomagnetism and Earth Planetary and Space Sciences (SGEPSS).

Timsit Y.,Aix - Marseille University
International Journal of Molecular Sciences | Year: 2013

Transient or long-term DNA self-assembly participates in essential genetic functions. The present review focuses on tight DNA-DNA interactions that have recently been found to play important roles in both controlling DNA higher-order structures and their topology. Due to their chirality, double helices are tightly packed into stable right-handed crossovers. Simple packing rules that are imposed by DNA geometry and sequence dictate the overall architecture of higher order DNA structures. Close DNA-DNA interactions also provide the missing link between local interactions and DNA topology, thus explaining how type II DNA topoisomerases may sense locally the global topology. Finally this paper proposes that through its influence on DNA self-assembled structures, DNA chirality played a critical role during the early steps of evolution. © 2013 by the authors; licensee MDPI, Basel, Switzerland.

Baffou G.,Aix - Marseille University | Quidant R.,ICFO - Institute of Photonic Sciences | Quidant R.,Catalan Institution for Research and Advanced Studies
Laser and Photonics Reviews | Year: 2013

Recent years have seen a growing interest in using metal nanostructures to control temperature on the nanoscale. Under illumination at its plasmonic resonance, a metal nanoparticle features enhanced light absorption, turning it into an ideal nano-source of heat, remotely controllable using light. Such a powerful and flexible photothermal scheme is the basis of thermo-plasmonics. Here, the recent progress of this emerging and fast-growing field is reviewed. First, the physics of heat generation in metal nanoparticles is described, under both continuous and pulsed illumination. The second part is dedicated to numerical and experimental methods that have been developed to further understand and engineer plasmonic-assisted heating processes on the nanoscale. Finally, some of the most recent applications based on the heat generated by gold nanoparticles are surveyed, namely photothermal cancer therapy, nano-surgery, drug delivery, photothermal imaging, protein tracking, photoacoustic imaging, nano-chemistry and optofluidics. Recent years have seen a growing interest in using metal nanostructures to control temperature on the nanoscale. Under illumination at its plasmonic resonance, a metal nanoparticle features enhanced light absorption, turning it into an ideal nano-source of heat, remotely controllable using light. Such a powerful and flexible photothermal scheme is the basis of thermo-plasmonics. Here, the recent progress of this emerging and fast-growing field is reviewed. First, the physics of heat generation in metal nanoparticles is described, under both continuous and pulsed illumination. The second part is dedicated to numerical and experimental methods that have been developed to further understand and engineer plasmonic-assisted heating processes on the nanoscale. Finally, some of the most recent applications based on the heat generated by gold nanoparticles are surveyed, namely photothermal cancer therapy, nano-surgery, drug delivery, photothermal imaging, protein tracking, photoacoustic imaging, nano-chemistry and optofluidics. © 2012 by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Barreto P.D.S.,Aix - Marseille University
Aging Clinical and Experimental Research | Year: 2010

Exercise and physical activity play an important role in physical frailty, but we do not know if they are markers, components and/or correlates of this syndrome. The purpose of this paper is briefly to discuss the potential roles played by physical activity and exercise on the development and progression of frailty, and to propose directions for future research in this field. Exercise practice lowers the levels of some frailty markers, such as tumor necrosis factor-alpha, interleukin-6, C-reactive protein, and uric acid, and also resistance to insulin. The influence of exercise on the main frailty domains is also well established in the literature. Exercise improves muscle strength, gait speed, cognition (particularly executive control related-tasks), weight maintenance, mood and, to a lesser extent, feelings of energy. Although exercise and physical activity positively influence the main frailty markers and domains, most findings were obtained for other elderly populations (e.g., healthy elderly, clinical populations). For future research, efforts must be made to define some key concepts (exercise or physical activity) in selecting study samples and in establishing intervention length. Attention must also be paid to identifying the most efficacious exercise interventions regarding type, frequency, intensity and session duration, and approaching a dose-response relationship between a physically active life-style and frailty. Thus, further research, especially longitudinal randomized controlled trials, is needed to understand the role of physical activity and exercise in the frailty syndrome. ©2010, Editrice Kurtis.

Reboul E.,French National Institute for Agricultural Research | Reboul E.,French Institute of Health and Medical Research | Reboul E.,Aix - Marseille University
Nutrients | Year: 2013

Vitamin A deficiency is a public health problem in most developing countries, especially in children and pregnant women. It is thus a priority in health policy to improve preformed vitamin A and/or provitamin A carotenoid status in these individuals. A more accurate understanding of the molecular mechanisms of intestinal vitamin A absorption is a key step in this direction. It was long thought that β-carotene (the main provitamin A carotenoid in human diet), and thus all carotenoids, were absorbed by a passive diffusion process, and that preformed vitamin A (retinol) absorption occurred via an unidentified energy-dependent transporter. The discovery of proteins able to facilitate carotenoid uptake and secretion by the enterocyte during the past decade has challenged established assumptions, and the elucidation of the mechanisms of retinol intestinal absorption is in progress. After an overview of vitamin A and carotenoid fate during gastro-duodenal digestion, our focus will be directed to the putative or identified proteins participating in the intestinal membrane and cellular transport of vitamin A and carotenoids across the enterocyte (i.e., Scavenger Receptors or Cellular Retinol Binding Proteins, among others). Further progress in the identification of the proteins involved in intestinal transport of vitamin A and carotenoids across the enterocyte is of major importance for optimizing their bioavailability. © 2013 by the authors; licensee MDPI, Basel, Switzerland.

Cardenas M.L.,Aix - Marseille University
FEBS Letters | Year: 2013

This article sketches the road from the establishment of the principles of enzyme kinetics, at the beginning of the 20th century, to the discovery of regulatory mechanisms and the models to explain them, from the middle of the century onwards. A long gap in time separates the two periods, in which technological advances were made that allowed the discovery of feedback inhibition and cooperativity. In particular, these discoveries and the theory needed to explain them could not have been made without knowledge of the major metabolic pathways and the enzymes and metabolites involved in them. © 2013 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

New-generation sequencing is already in routine clinical use, notably for the search of actionable mutations in oncology, and for non-invasive prenatal diagnostics. More applications are developing and will soon enter clinical practice. © 2014 médecine/sciences - Inserm.

Olive G.,Aix - Marseille University
Mathematics of Control, Signals, and Systems | Year: 2012

In this work, we study the null-controllability properties of linear parabolic systems with constant coefficients in the case where several controls are acting on different distributed subdomains and/or on the boundary.We prove a Kalman rank condition in the one-dimensional case. In the case where only distributed controls are considered, we also establish related results such as a Carleman estimate. © Springer-Verlag London Limited 2011.

Soloshonok V.A.,University of the Basque Country | Soloshonok V.A.,Ikerbasque | Roussel C.,Aix - Marseille University | Kitagawa O.,Shibaura Institute of Technology | And 3 more authors.
Chemical Society Reviews | Year: 2012

This tutorial review describes the self-disproportionation of enantiomers (SDE) of chiral, non-racemic compounds, subjected to chromatography on an achiral stationary phase using an achiral eluent, which leads to the substantial enantiomeric enrichment and the corresponding depletion in different fractions, as compared to the enantiomeric composition of the starting material. The physicochemical background of SDE is a dynamic formation of homo- or heterochiral dimeric or oligomeric aggregates of different chromatographic behavior. This phenomenon is of a very general nature as the SDE has been reported for different classes of organic compounds bearing various functional groups and possessing diverse elements of chirality (central, axial and helical chirality). The literature data dis