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University of Paris-Sud is a French university distributed among several campuses in the southern suburb of Paris . The main campus is located in Orsay . This university is a member of the UniverSud Paris.Paris-Sud is one of the largest and most renowned French universities, particularly in science and mathematics. Paris-Sud is ranked 2nd in France, 7th in Europe and 39th worldwide by the 2013 Academic Ranking of World Universities . Furthermore, in this latest edition of ARWU ranking, the university is ranked 15th globally in the field of Natural science and Mathematics; in the five general subject rankings, the university is ranked 7th in mathematics and 19th in physics. Wikipedia.

Tremblay N.,Agriculture and Agri Food Canada | Wang Z.,Agriculture and Agri Food Canada | Cerovic Z.G.,University Paris - Sud
Agronomy for Sustainable Development | Year: 2012

The optimization of nitrogen (N) fertilization is the object of intense research efforts around the world. Overfertilization is commonly used as a form of insurance against uncertain soil fertility level. However, this practice results in lower nitrogen use efficiency, high levels of residual N after harvest, and losses in the environment. Determining an N recommendation that would preserve actual crop requirements, profitability of the farm, and quality of the environment has been subjected to a number of research initiatives with a variable degree of success. On one hand, soil tests are capable of estimating the intensity of N release at any point in time, but rarely the capacity factor over a longer period. On the other hand, in the context of in-season N applications, crops are often considered good integrators of factors such as the presence of mineral N, climatic conditions, soil properties, and crop management. Strategies have been proposed with plant sensor-based diagnostic information for N recommendations, but the sensitivity of reflectance-based parameters alone do not provide complete satisfaction (delayed sensitivity, need of specific chlorophyll, biomass or cover fraction ranges, lack of specificity to the N stress). Fluorescence sensing methods have been used to monitor crop physiology for years, and they may offer solutions for N status diagnosis over reflectance-based methods. In this paper, we review three plant fluorescence components related to four sensing approaches-variable chlorophyll fluorescence, leaf chlorophyll content-related fluorescence emission ratio, blue-green fluorescence, and epidermal screening of chlorophyll fluorescence by phenolic compounds-from the perspective of their relevance to N fertilization management of agricultural crops. We examine the existence of N-induced changes in each case, together with applications and limitations of the approach. Among these approaches, the fluorescence emission ratio method is the most important and the most widely used to date. However, blue-green fluorescence and epidermal screening of chlorophyll fluorescence by phenolic compounds has also received a great deal of attention particularly with the recent commercial release of instruments which can measure in real time and in vivo both the leaf chlorophyll content and several phenolic compounds (anthocyanins, flavonoïds, hydroxycinnamic acids). Overall, our conclusion is that fluorescence-based technologies allow for highly sensitive plant N status information, independently from soil interference, leaf area, or biomass status. They also allow for probing not only the chlorophyll status but also other physiological parameters known to react to N fertility conditions. These new parameters have the potential to provide new N status indicators that can be assessed remotely in a precision agriculture context. © INRA and Springer Science+Business Media B.V. 2011.

Benoit-Levy A.,CNRS Paris Institute of Astrophysics | Chardin G.,University Paris - Sud
Astronomy and Astrophysics | Year: 2012

The ΛCDM standard model, although an excellent parametrization of the present cosmological data, contains two as yet unobserved components, dark matter and dark energy, that constitute more than 95% of the Universe. Faced with this unsatisfactory situation, we study an unconventional cosmology, the Dirac-Milne universe, a matter-antimatter symmetric cosmology, in which antimatter is supposed to present a negative active gravitational mass. The main feature of this cosmology is the linear evolution of the scale factor with time, which directly solves the age and horizon problems of a matter-dominated universe. We study the concordance of this model to the cosmological test of type Ia supernovae distance measurements and calculate the theoretical primordial abundances of light elements for this cosmology. We also show that the acoustic scale of the cosmic microwave background naturally emerges at the degree scale despite an open geometry. © 2012 ESO.

PURPOSE OF REVIEW: Transthyretin familial amyloid polyneuropathy (TTR-FAP) is a highly disabling, life-threatening disease characterized by progressive sensorimotor and autonomic neuropathy. The profile of the disease across Europe is inadequately understood at present. RECENT FINDINGS: The incidence and clinical presentation of TTR-FAP varies widely within Europe, with early and late-onset disease subtypes. In those regions in which the disease is endemic (Portugal, Sweden, Cyprus, and Majorca), a Val30Met substitution in the TTR gene is the predominant genetic cause, whereas in the rest of Europe, cases of TTR-FAP are mainly sporadic with genetic heterogeneity. Current management strategies lack cohesion and patients can experience years of misdiagnosis and suboptimal treatment. SUMMARY: The article aims to disseminate the findings and recommendations from two recent meetings of the European Network for TTR-FAP (ATTReuNET), a panel comprising representatives from 10 European countries (Bulgaria, Cyprus, France, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, and Turkey) with expertise in the diagnosis and management of TTR-FAP. We explore the epidemiology and genetic mark of TTR-FAP across Europe and assess current management strategies, with a view to developing an alternative framework – a networked approach to disease management with an emphasis on collaboration and sharing of best practice. Copyright © 2016 Wolters Kluwer Health, Inc. All rights resereved.

Helie T.,French National Center for Scientific Research | Laroche B.,University Paris - Sud
IEEE Transactions on Automatic Control | Year: 2011

In this paper, the Volterra series decomposition of a class of single-input time-invariant systems, analytic in state and affine in input, is analyzed. Input-to-state convergence results are obtained for several typical norms (L ∞([O,T]), L ∞ (R +) as well as exponentially weighted norms). From the standard recursive construction of Volterra kernels, new estimates of the kernel norms are derived. The singular inversion theorem is then used to obtain the main result of the paper, namely, an easily computable bound of the convergence radius. Guaranteed error bounds for the truncated series are also provided. The relevance of the method is illustrated in several examples. © 2010 IEEE.

Salanne M.,Paris-Sorbonne University | Salanne M.,University Paris - Sud
Physical Chemistry Chemical Physics | Year: 2015

Room temperature ionic liquids (RTILs) are solvent with unusual properties, which are difficult to characterize experimentally because of their intrinsic complexity (large number of atoms, strong Coulomb interactions). Molecular simulations have therefore been essential in our understanding of these systems. Depending on the target property and on the necessity to account for fine details of the molecular structure of the ions, a large range of simulation techniques are available. Here I focus on classical molecular dynamics, in which the level of complexity of the simulation, and therefore the computational cost, mostly depends on the force field. Depending on the representation of the ions, these are either classified as all-atom or coarse-grained. In addition, all-atom force fields may account for polarization effects if necessary. The most widely used methods for RTILs are described together with their main achievements and limitations. © the Owner Societies 2015.

Bonnin R.A.,University Paris - Sud
PloS one | Year: 2012

The current spread of the gene encoding the metallo-ß-lactamase NDM-1 in Enterobacteriaceae is linked to a variety of surrounding genetic structures and plasmid scaffolds. The whole sequence of plasmid pGUE-NDM carrying the bla(NDM-1) gene was determined by high-density pyrosequencing and a genomic comparative analysis with other bla(NDM-1)-negative IncFII was performed. Plasmid pGUE-NDM replicating in Escherichia coli confers resistance to many antibiotic molecules including β-lactams, aminoglycosides, trimethoprim, and sulfonamides. It is 87,022 bp in-size and carries the two β-lactamase genes bla(NDM-1) and bla(OXA-1), together with three aminoglycoside resistance genes aacA4, aadA2, and aacC2. Comparative analysis of the multidrug resistance locus contained a module encompassing the bla(NDM-1) gene that is actually conserved among different structures identified in other enterobacterial isolates. This module was constituted by the bla(NDM-1) gene, a fragment of insertion sequence ISAba125 and a bleomycin resistance encoding gene. This is the first characterized bla(NDM-1)-carrying IncFII-type plasmid. Such association between the bla(NDM-1) gene and an IncFII-type plasmid backbone is extremely worrisome considering that this plasmid type is known to spread efficiently, as examplified with the worldwide dissemination of bla(CTX-M-15)-borne IncFII plasmids.

Fieulaine S.,French National Center for Scientific Research | Desmadril M.,University Paris - Sud | Meinnel T.,French National Center for Scientific Research | Giglione C.,French National Center for Scientific Research
Acta Crystallographica Section D: Biological Crystallography | Year: 2014

Peptide deformylases (PDFs), which are essential and ubiquitous enzymes involved in the removal of the N-formyl group from nascent chains, are classified into four subtypes based on the structural and sequence similarity of specific conserved domains. All PDFs share a similar three-dimensional structure, are functionally interchangeable in vivo and display similar properties in vitro, indicating that their molecular mechanism has been conserved during evolution. The human mitochondrial PDF is the only exception as despite its conserved fold it reveals a unique substrate-binding pocket together with an unusual kinetic behaviour. Unlike human PDF, the closely related mitochondrial PDF1As from plants have catalytic efficiencies and enzymatic parameters that are similar to those of other classes of PDFs. Here, the aim was to identify the structural basis underlying the properties of human PDF compared with all other PDFs by focusing on plant mitochondrial PDF1A. The construction of a chimaera composed of plant PDF1A with the nonrandom substitutions found in a conserved motif of its human homologue converted it into an enzyme with properties similar to the human enzyme, indicating the crucial role of these positions. The crystal structure of this human-like plant PDF revealed that substitution of two residues leads to a reduction in the volume of the ligand-binding site together with the introduction of negative charges, unravelling the origin of the weak affinity of human PDF for its substrate. In addition, the substitution of the two residues of human PDF modifies the transition state of the reaction through alteration of the network of interactions between the catalytic residues and the substrate, leading to an overall reduced reaction rate. © 2014 International Union of Crystallography.

Majumdar S.N.,University Paris - Sud
Physica A: Statistical Mechanics and its Applications | Year: 2010

In these lecture notes I will discuss the universal first-passage properties of a simple correlated discrete-time sequence x0=0,x1,x2,⋯,xn up to n steps where xi represents the position at step i of a random walker hopping on a continuous line by drawing independently, at each time step, a random jump length from an arbitrary symmetric and continuous distribution (it includes, e.g., the Lévy flights). I will focus on the statistics of two extreme observables associated with the sequence: (i) its global maximum and the time step at which the maximum occurs and (ii) the number of records in the sequence and their ages. I will demonstrate how the universal statistics of these observables emerge as a consequence of PollaczekSpitzer formula and the associated Sparre Andersen theorem. © 2010 Elsevier B.V. All rights reserved.

Brucker A.D.,SAP | Wolff B.,University Paris - Sud
Formal Aspects of Computing | Year: 2013

HOL-TestGen is a specification and test case generation environment extending the interactive theorem prover Isabelle/HOL. As such, Testgen allows for an integrated workflow supporting interactive theorem proving, test case generation, and test data generation. The HOL-TestGen method is two-staged: first, the original formula is partitioned into test cases by transformation into a normal form called test theorem. Second, the test cases are analyzed for ground instances (the test data) satisfying the constraints of the test cases. Particular emphasis is put on the control of explicit test-hypotheses which can be proven over concrete programs. Due to the generality of the underlying framework, our system can be used for black-box unit, sequence, reactive sequence and white-box test scenarios. Although based on particularly clean theoretical foundations, the system can be applied for substantial case-studies. © 2012 British Computer Society.

Codogno P.,University Paris - Sud
Current Biology | Year: 2011

Autophagy is inhibited by the mTOR signaling pathway, which is stimulated by increased amino acid levels. When cellular energy production is compromised, AMP-activated protein kinase is activated, mTOR is inhibited and autophagy is stimulated. Two recent studies have shed light on the molecular mechanism by which AMPK controls autophagic flux. © 2011 Elsevier Ltd All rights reserved.

Langevin D.,University Paris - Sud | Monroy F.,Complutense University of Madrid
Current Opinion in Colloid and Interface Science | Year: 2010

In this review, we describe interfacial rheology studies of polymer monolayers at the air-water interface. Since polyelectrolytes are usually soluble in water, the formation of surface monolayers requires the presence of a surfactant of opposite charge. The first part of the review is dedicated to these mixed monolayers. The second part is related to neutral monolayers that can be either adsorbed or deposited at the interface. Interfacial rheology studies of these systems are still scarce, despite a considerable interest: insoluble polymer monolayers in two dimensions are suitable model systems for the tests of polymer theories in two dimensions, such as and glass transition. The rheology of soluble polymer monolayers has important connections with the dynamic properties of dispersions stabilized with these polymers. © 2010 Elsevier Ltd.

Forterre P.,Institute Pasteur Paris | Forterre P.,University Paris - Sud | Krupovic M.,Institute Pasteur Paris | Prangishvili D.,Institute Pasteur Paris
Trends in Microbiology | Year: 2014

It has been claimed that giant DNA viruses represent a separate, fourth domain of life in addition to the domains of Bacteria, Archaea, and Eukarya. Such classification disregards fundamental differences between the two types of living entities - viruses and cells - and results in confusion and controversies in evolutionary scenarios. We highlight these problems and emphasize the importance of restricting the term 'domain' to the descendants of the last universal cellular ancestor (LUCA), based on the shared ribosome structure. We suggest tracing phylogeny of viruses along evolutionary lineages primarily defined by virion architectures and the structures of the major capsid proteins. © 2014 Elsevier Ltd.

Klein C.,University of Burgundy | Saut J.-C.,University Paris - Sud
Journal of Nonlinear Science | Year: 2012

We first review the known mathematical results concerning the Kadomtsev- Petviashvili type equations. Then we perform numerical simulations to analyze various qualitative properties of the equations: blow-up versus long time behavior, stability and instability of solitary waves. © Springer Science+Business Media, LLC 2012.

Schorghofer N.,University of Hawaii at Manoa | Forget F.,University Paris - Sud
Icarus | Year: 2012

Ice buried beneath a thin layer of soil has been revealed by neutron spectroscopy and explored by the Phoenix Mars Lander. It has also been exposed by recent impacts. This subsurface ice is thought to lose and gain volume in response to orbital variations (Milankovitch cycles). We use a powerful numerical model to follow the growth and retreat of near-surface ice as a result of regolith-atmosphere exchange continuously over millions of years. If a thick layer of almost pure ice has been deposited recently, it has not yet reached equilibrium with the atmospheric water vapor and may still remain as far equatorward as 43°N, where ice has been revealed by recent impacts. A potentially observable consequence is present-day humidity output from the still retreating ice. We also demonstrate that in a sublimation environment, subsurface pore ice can accumulate in two ways. The first mode, widely known, is the progressive filling of pores by ice over a range of depths. The second mode occurs on top of an already impermeable ice layer; subsequent ice accumulates in the form of pasted on horizontal layers such that beneath the ice table, the pores are completely full with ice. Most or all of the pore ice on Mars today may be of the second type. At the Phoenix landing site, where such a layer is also expected to exist above an underlying ice sheet, it may be extremely thin, due to exceptionally small variations in ice stability over time. © 2012 Elsevier Inc..

Yang Z.,University Pierre and Marie Curie | Lisiecki I.,University Pierre and Marie Curie | Walls M.,University Paris - Sud | Pileni M.-P.,University Pierre and Marie Curie
ACS Nano | Year: 2013

Here it is demonstrated that the diffusion process of oxygen in Co nanoparticles is controlled by their 2D ordering and crystallinity. The crystallinity of isolated Co nanoparticles deposited on a substrate does not play any role in the oxide formation. When they are self-assembled in 2D superlattices, the oxidation process is slowed and produces either core/shell (Co/CoO) nanoparticles or hollow CoO nanocrystals. This is attributed to the decrease in the oxygen diffusion rate when the nanoparticles are interdigitated. Initially, polycrystalline nanoparticles form core/shell (Co/CoO) structures, while for single-domain hexagonal close-packed Co nanocrystals, the outward diffusion of Co ions is favored over the inward diffusion of oxygen, producing hollow CoO single-domain nanocrystals. © 2013 American Chemical Society.

Cervical hematoma with airway compromise is a severe complication that may be rapidly lethal or result in irreversible cerebral anoxia if the hematoma is not urgently decompressed. It is therefore indispensable to know the essential relevant elements as well as predictive criteria for this complication before envisioning ambulatory thyroidectomy. The Association francophone de chirurgie endocrinienne (AFCE) sought to answer several questions raised by the proposal of ambulatory thyroidectomy and to propose recommendations based on a review of the literature, an inquiry sent out to members of the AFCE, and an in-depth research of the medicolegal risks involved, based essentially on jurisprudence. The details scrutinized included preoperative selection criteria, the characteristics of the operation and the basic elements of postoperative surveillance. The standard today is at least an overnight hospital stay. In fact, hospital stay can be less than 24h because the risk of cervical compressive hematoma is very unusual beyond this interval. Ambulatory (outpatient) thyroidectomy (0 nights) is possible under certain conditions for highly selected patients according to criteria described in the literature that also define relative contra-indications. In case of life-threatening or functional complications, the surgeon stands first in the line of responsibility. The surgeon must therefore ensure that the patient and family were fully informed of the contra-indications, the normal course of postoperative events, of pertinent elements of postoperative surveillance and of the conditions under which the patient can be safely discharged. The surgeon must also realize that this type of management is time-consuming. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Oil-producing flowers related to oil-bee pollination are a major innovation in Neotropical and Mexican Iridaceae. In this study, phylogenetic relationships were investigated among a wide array of New World genera of the tribes Sisyrinchieae, Trimezieae and Tigridieae (Iridaceae: Iridoideae) and the evolution of floral glandular structures, which are predominantly trichomal elaiophores, was examined in relation to the diversification of New World Iridaceae. Phylogenetic analyses based on seven molecular markers obtained from 97 species were conducted to produce the first extensive phylogeny of the New World tribes of subfamily Iridoideae. The resulting phylogenetic hypothesis was used to trace the evolutionary history of glandular structures present in the flowers of numerous species in each tribe. Hypotheses of differential diversification rates among lineages were also investigated using both topological and Binary-State Speciation and Extinction methods. Floral glandular structures and especially trichomal elaiophores evolved multiple times independently in the American tribes of Iridoideae. The distribution pattern of species displaying glandular trichomes across the phylogeny reveals lability in the pollination system and suggests that these structures may have played a significant role in the diversification of the Iridoideae on the American continent.

Bretes H.,University Paris Diderot | Bretes H.,University Paris - Sud
Nucleic acids research | Year: 2014

Assembly of messenger ribonucleoparticles (mRNPs) is a pivotal step in gene expression, but only a few molecular mechanisms contributing to its regulation have been described. Here, through a comprehensive proteomic survey of mRNP assembly, we demonstrate that the SUMO pathway specifically controls the association of the THO complex with mRNPs. We further show that the THO complex, a key player in the interplay between gene expression, mRNA export and genetic stability, is sumoylated on its Hpr1 subunit and that this modification regulates its association with mRNPs. Altered recruitment of the THO complex onto mRNPs in sumoylation-defective mutants does not affect bulk mRNA export or genetic stability, but impairs the expression of acidic stress-induced genes and, consistently, compromises viability in acidic stress conditions. Importantly, inactivation of the nuclear exosome suppresses the phenotypes of the hpr1 non-sumoylatable mutant, showing that SUMO-dependent mRNP assembly is critical to allow a specific subset of mRNPs to escape degradation. This article thus provides the first example of a SUMO-dependent mRNP-assembly event allowing a refined tuning of gene expression, in particular under specific stress conditions.

Jones A.P.,French National Center for Scientific Research | Jones A.P.,University Paris - Sud
Astronomy and Astrophysics | Year: 2012

Context. The properties of hydrogenated amorphous carbon (a-C:H) dust evolve in response to the local radiation field in the interstellar medium (ISM) and the evolution of these properties is particularly dependent upon the particle size. Aims. A model for finite-sized, low-temperature amorphous hydrocarbon particles, based on the microphysical properties of random and defected networks of carbon and hydrogen atoms, with surfaces passivated by hydrogen atoms, has been developed. Methods. The eRCN/DG and the optEC (s) models have been combined, adapted and extended into a new optEC (s)(a) model that is used to calculate the optical properties of hydrocarbon grain materials down into the sub-nanometre size regime, where the particles contain only a few tens of carbon atoms. Results. The optEC (s)(a) model predicts a continuity in properties from large to small (sub-nm) carbonaceous grains. Tabulated data of the size-dependent optical constants (from EUV to cm wavelengths) for a-C:H (nano-)particles as a function of the bulk material band gap [E g(bulk)], or equivalently the hydrogen content, are provided. The effective band gap [E g(eff.)] is found to be significantly larger than E g(bulk) for hydrogen-poor a-C(:H) nano-particles and their predicted long-wavelength (λ > 30 μm) optical properties differ from those derived for interstellar polycyclic aromatic hydrocarbons (PAHs). Conclusions. The optEC (s)(a) model is used to investigate the size-dependent structural and spectral evolution of a-C(:H) materials under ISM conditions, including: the IR-FUV extinction, the 217 nm bump and the infrared emission bands. The model makes several predictions that can be tested against observations. © 2012 ESO.

Deschamps P.,University Paris - Sud
Acta Societatis Botanicorum Poloniae | Year: 2014

Eukaryotes acquired the ability to process photosynthesis by engulfing a cyanobacterium and transforming it into a genuine organelle called the plastid. This event, named primary endosymbiosis, occurred once more than a billion years ago, and allowed the emergence of the Archaeplastida, a monophyletic supergroup comprising the green algae and plants, the red algae and the glaucophytes. Of the other known cases of symbiosis between cyanobacteria and eukaryotes, none has achieved a comparable level of cell integration nor reached the same evolutionary and ecological success than primary endosymbiosis did. Reasons for this unique accomplishment are still unknown and difficult to comprehend. The exploration of plant genomes has revealed a considerable amount of genes closely related to homologs of Chlamydiae bacteria, and probably acquired by horizontal gene transfer. Several studies have proposed that these transferred genes, which are mostly involved in the functioning of the plastid, may have helped the settlement of primary endosymbiosis. Some of these studies propose that Chlamydiae and cyanobacterial symbionts coexisted in the eukaryotic host of the primary endosymbiosis, and that Chlamydiae provided solutions for the metabolic symbiosis between the cyanobacterium and the host, ensuring the success of primary endosymbiosis. In this review, I present a reevaluation of the contribution of Chlamydiae genes to the genome of Archaeplastida and discuss the strengths and weaknesses of this tripartite model for primary endosymbiosis.

Rezac J.,Czech Institute of Organic Chemistry And Biochemistry | De La Lande A.,University Paris - Sud
Journal of Chemical Theory and Computation | Year: 2015

Separation of the energetic contribution of charge transfer to interaction energy in noncovalent complexes would provide important insight into the mechanisms of the interaction. However, the calculation of charge-transfer energy is not an easy task. It is not a physically well-defined term, and the results might depend on how it is described in practice. Commonly, the charge transfer is defined in terms of molecular orbitals; in this framework, however, the charge transfer vanishes as the basis set size increases toward the complete basis set limit. This can be avoided by defining the charge transfer in terms of the spatial extent of the electron densities of the interacting molecules, but the schemes used so far do not reflect the actual electronic structure of each particular system and thus are not reliable. We propose a spatial partitioning of the system, which is based on a charge transfer-free reference state, namely superimposition of electron densities of the noninteracting fragments. We show that this method, employing constrained DFT for the calculation of the charge-transfer energy, yields reliable results and is robust with respect to the strength of the charge transfer, the basis set size, and the DFT functional used. Because it is based on DFT, the method is applicable to rather large systems. © 2015 American Chemical Society.

Corcos D.,University Paris - Sud
Scandinavian Journal of Immunology | Year: 2015

Adaptive immunity is a complex system that appeared twice in vertebrates (in gnathostomes and in jawless fish) although it is not required for invertebrate defence. The adaptive immune system is tightly associated with self-non-self discrimination, and it is now clear that this interplay is not limited to the prevention of autoreactivity. Micro-organisms are usually considered for their pathogenicity or symbiotic ability, but, for most small metazoans, they mainly constitute food. Vertebrates are characterized by feeding by predation on larger preys, when compared to their ancestors who were filter feeders and ate micro-organisms. Predation gives a strong selective advantage, not only due to the availability of new food resources but also by the ability to eliminate competitors for environmental resources (intraguild predation (IGP)). Unlike size-structured IGP, intraspecific predation of juveniles, zygotes or gametes can be detrimental for species fitness in some circumstances. The ability of individuals to recognize highly polymorphic molecules on the surface of gametes present in the plankton and so distinguish self versus non-self gametes might have constituted a strong selective advantage in intraspecific competition. Here, I propose the theory that the capacity to rearrange receptors has been selected in ancestral vertebrates as a consequence of this strong need for discriminating between hetero-cannibalism versus filial cannibalism. This evolutionary origin sheds light on presently unexplained features of the immune system, including the existence of regulatory T cells and of non-pathogenic natural autoimmunity. © 2015 The Foundation for the Scandinavian Journal of Immunology.

Jansen Y.,University Paris - Sud | Dragicevic P.,French Institute for Research in Computer Science and Automation
IEEE Transactions on Visualization and Computer Graphics | Year: 2013

We present an interaction model for beyond-desktop visualizations that combines the visualization reference model with the instrumental interaction paradigm. Beyond-desktop visualizations involve a wide range of emerging technologies such as wall-sized displays, 3D and shape-changing displays, touch and tangible input, and physical information visualizations. While these technologies allow for new forms of interaction, they are often studied in isolation. New conceptual models are needed to build a coherent picture of what has been done and what is possible. We describe a modified pipeline model where raw data is processed into a visualization and then rendered into the physical world. Users can explore or change data by directly manipulating visualizations or through the use of instruments. Interactions can also take place in the physical world outside the visualization system, such as when using locomotion to inspect a large scale visualization. Through case studies we illustrate how this model can be used to describe both conventional and unconventional interactive visualization systems, and compare different design alternatives. © 1995-2012 IEEE.

Bogomolny E.,University Paris - Sud
Journal of Physics A: Mathematical and Theoretical | Year: 2010

The asymptotic behaviour of the mean spectral density for the product of N × N random unitary matrices distributed according to the Haar measure and a fixed diagonal matrix is investigated. The large N limit of the exact expression derived by Wei and Fyodorov (2008 J. Phys. A: Math. Theor. 41 502001) is calculated by a modification of the saddle point method. It is shown that in the bulk the result coincides with the one obtained within the free probability theory by Haagerup and Larsen (2000 J. Funct. Anal. 176 331). Close to the edge points of the bulk asymptotics, the mean density for large N is described by a universal function depending on a certain scaling variable. The large deviation formulae valid outside the bulk are also derived. Obtained formulae agree well with the results of direct numerical calculations. © 2010 IOP Publishing Ltd.

Jones A.P.,French National Center for Scientific Research | Jones A.P.,University Paris - Sud
Astronomy and Astrophysics | Year: 2012

Context. The compositional properties of hydrogenated amorphous carbons are known to evolve in response to the local conditions. Aims. We present a model for low-temperature, amorphous hydrocarbon solids, based on the microphysical properties of random and defected networks of carbon and hydrogen atoms, that can be used to study and predict the evolution of their properties in the interstellar medium. Methods. We adopt an adaptable and prescriptive approach to model these materials, which is based on a random covalent network (RCN) model, extended here to a full compositional derivation (the eRCN model), and a defective graphite (DG) model for the hydrogen poorer materials where the eRCN model is no longer valid. Results. We provide simple expressions that enable the determination of the structural, infrared and spectral properties of amorphous hydrocarbon grains as a function of the hydrogen atomic fraction, X H. Structural annealing, resulting from hydrogen atom loss, results in a transition from H-rich, aliphatic-rich to H-poor, aromatic-rich materials. Conclusions. The model predicts changes in the optical properties of hydrogenated amorphous carbon dust in response to the likely UV photon-driven and/or thermal annealing processes resulting, principally, from the radiation field in the environment. We show how this dust component will evolve, compositionally and structurally in the interstellar medium in response to the local conditions. © 2012 ESO.

Jones A.P.,French National Center for Scientific Research | Jones A.P.,University Paris - Sud
Astronomy and Astrophysics | Year: 2012

Context. The properties of hydrogenated amorphous carbon (a-C:H) dust are known to evolve in response to the local conditions. Aims. We present an adaptable model for the determination of the optical properties of low-temperature, interstellar a-C:H grains that is based on the fundamental physics of their composition. Methods. The imaginary part of the refractive index, k, for a-C:H materials, from 50eV to cm wavelengths, is derived and the real part, n, of the refractive index is then calculated using the Kramers-Kronig relations. Results. The formulated optEC(s) model allows a determination of the complex dielectric function, ε, and refractive index, m(n,k), for a-C:H materials as a continuous function the band gap, Eg, which is shown to lie in the range ≈-0.1 to 2.7 eV. We provide expressions that enable a determination of their optical constants and tabulate m(n,k,Eg) for 14 different values of Eg. We explore the evolution of the likely extinction and emission behaviours of a-C:H grains and estimate the relevant transformation time-scales. Conclusions. With the optEC(s) model we are able to predict how the optical properties of an a-C:H dust component in the interstellar medium will evolve in response to, principally, the local interstellar radiation field. The evolution of a-C:H materials appears to be consistent with many dust extinction, absorption, scattering and emission properties, and also with H2 molecule, daughter "PAH" and hydrocarbon molecule formation resulting from its photo-driven decomposition. © 2012 ESO.

Kaffy J.,University Paris - Sud
Current pharmaceutical design | Year: 2013

Regulator of a vast array of vital cellular processes including cell-cycle progression, apoptosis and antigen presentation, the proteasome represents a major therapeutic target. Therefore, selective inhibitors of the proteasome are promising candidates to develop new treatments for diseases like inflammation, immune diseases and cancer. For proof, the boronic acid, Bortezomib has been approved for treating incurable multiple myeloma in 2003 and mantle lymphoma in 2006 and five others proteasome inhibitors are currently in clinical trials for treatment of different cancers. These compounds and many described proteasome inhibitors interact covalently with the active site of the enzyme through an electrophilic reactive function. Non-covalent inhibitors, mainly peptides, pseudopeptides and some organic compounds, have been less widely investigated. Devoid of reactive function prone to nucleophilic attack, they could offer the advantage of an improved selectivity, a less excessive reactivity and instability which are often associated with side effects in therapeutics. This review highlights the current state of research in the field of non-covalent proteasome inhibitors.

Juvela M.,University of Helsinki | Ysard N.,University of Helsinki | Ysard N.,University Paris - Sud
Astronomy and Astrophysics | Year: 2012

Context. With the current Herschel and Planck satellite missions, there is strong interest in the interpretation of the details of the sub-millimetre dust emission spectra. The data contain information on the properties of the interstellar clouds and the physics of the dust grains. A lot of work has been done to understand the negative correlation observed between the spectral index β Obs and the colour temperature T C that in the χ 2 fits is partly caused by the observational noise. Aims. In the (T C, β Obs) plane, the confidence regions are elongated, banana-shaped structures. Previous studies have indicated that the errors may exhibit strongly asymmetric features that have important consequences for the investigation of individual objects and the interpretation of the relation between the T C and β Obs parameters. We study under which conditions the confidence regions exhibit such anomalous, strongly non-Gaussian behaviour that could affect the interpretation of the observed (T C, β Obs) relations. Methods. We examined a set of modified black body spectra and spectra calculated from radiative transfer models of filamentary interstellar clouds. We analysed simulated observations at discrete wavelengths between 100 μm and 850 μm. We performed modified black body fits and examined the structure of the χ 2(T C, β Obs) function of the fits. Results. We demonstrate cases where, when the signal-to-noise ratio is low, the χ 2 has multiple local minima in the (T C, β Obs) plane. A small change in the weighting of the data points can cause the solution to jump to completely different values. In particular, if there is noise, the analysis of spectra with T > 10 K and β Obs ≈ 2 can lead to a separate population of solutions with much lower colour temperature and higher spectral indices. The anomalies are caused by the noise. However, the tendency to show multiple χ 2 minima depends on the model (in part via the influence on the signal-to-noise ratios) and on the set of wavelengths included in the analysis. Deviations from the underlying assumption of a single modified black body spectrum are not significant. Conclusions. The presence of several local minima implies that the results obtained from the χ 2 minimisation depend on the starting point of the optimisation and may correspond to non-global minima. Because of the strongly non-Gaussian nature of the errors, the obtained (T C, β Obs) distribution may be contaminated by a few solutions with unrealistically low colour temperatures and high spectral indices. Proper weighting must be applied to avoid the determination of the β Obs(T C) relation to be unduly affected by these measurements. © 2012 ESO.

Mazenc F.,Supelec | Niculescu S.-I.,University Paris - Sud
Automatica | Year: 2011

For time-varying forward-complete nonlinear systems with delay in the input, a new reduction model approach is proposed. It presents three advantages. First, the corresponding control laws do not include distributed terms. Second, it yields closed-loop systems with positive solutions that can be easily derived. Finally, the stabilized systems possess some robustness properties that can be estimated. © 2011 Elsevier Ltd. All rights reserved.

Casas J.,CNRS Research Institute of Insect Biology | Dangles O.,University Paris - Sud
Annual Review of Entomology | Year: 2010

Terrestrial and aquatic arthropods sense fluid flow in many behavioral and ecological contexts, using dedicated, highly sensitive mechanosensory hairs, which are often abundant. Strong similarities exist in the biomechanics of flow sensors and in the sensory ecology of insects, arachnids, and crustaceans in their respective fluid environments. We extend these considerations to flow in sand and its implications for flow sensing by arthropods inhabiting this granular medium. Finally, we highlight the need to merge the various findings of studies that have focused on different arthropods in different fluids. This could be achieved using the unique combination, for sensory ecology, of both a workable and well-accepted mathematical model for hair-based flow sensing, both in air and water, and microelectronic mechanical systems microtechnology to tinker with physical models. © 2010 by Annual Reviews All rights reserved.

Krupovic M.,Institute Pasteur Paris | Forterre P.,Institute Pasteur Paris | Forterre P.,University Paris - Sud
PLoS ONE | Year: 2011

The Microviridae comprises icosahedral lytic viruses with circular single-stranded DNA genomes. The family is divided into two distinct groups based on genome characteristics and virion structure. Viruses infecting enterobacteria belong to the genus Microvirus, whereas those infecting obligate parasitic bacteria, such as Chlamydia, Spiroplasma and Bdellovibrio, are classified into a subfamily, the Gokushovirinae. Recent metagenomic studies suggest that members of the Microviridae might also play an important role in marine environments. In this study we present the identification and characterization of Microviridae-related prophages integrated in the genomes of species of the Bacteroidetes, a phylum not previously known to be associated with microviruses. Searches against metagenomic databases revealed the presence of highly similar sequences in the human gut. This is the first report indicating that viruses of the Microviridae lysogenize their hosts. Absence of associated integrase-coding genes and apparent recombination with dif-like sequences suggests that Bacteroidetes-associated microviruses are likely to rely on the cellular chromosome dimer resolution machinery. Phylogenetic analysis of the putative major capsid proteins places the identified proviruses into a group separate from the previously characterized microviruses and gokushoviruses, suggesting that the genetic diversity and host range of bacteriophages in the family Microviridae is wider than currently appreciated. © 2011 Krupovic, Forterre.

Ellwanger U.,University Paris - Sud
Journal of High Energy Physics | Year: 2012

A natural region in the parameter space of the NMSSM can accomodate a CP-even Higgs boson with a mass of about 125GeV and, simultaneously, an enhanced cross section times branching ratio in the di-photon channel. This happens in the case of strong singlet-doublet mixing, when the partial width of a 125GeV Higgs boson into bb̄ is strongly reduced. In this case, a second lighter CP-even Higgs boson is potentially also observable at the LHC.

Langevin D.,University Paris - Sud
Current Opinion in Colloid and Interface Science | Year: 2015

The mechanisms for bubble coalescence in the absence of surfactants were clarified, including for salt solutions. No complete model is available yet for surfactant solutions. The notion of critical applied pressure for film rupture, decreasing with increasing film size, appears applicable to foam films, emulsion films and even asymmetric films. © 2015 Elsevier Ltd.

Gabelli J.,University Paris - Sud | Feve G.,Ecole Normale Superieure de Paris | Berroir J.-M.,Ecole Normale Superieure de Paris | Placais B.,Ecole Normale Superieure de Paris
Reports on Progress in Physics | Year: 2012

We review the first experiment on dynamic transport in a phase-coherent quantum conductor. In our discussion, we highlight the use of time-dependent transport as a means of gaining insight into charge relaxation on a mesoscopic scale. For this purpose, we studied the ac conductance of a model quantum conductor, i.e. the quantum RC circuit. Prior to our experimental work, Büttiker et al (1993 Phys. Lett. A 180 364-9) first worked on dynamic mesoscopic transport in the 1990s. They predicted that the mesoscopic RC circuit can be described by a quantum capacitance related to the density of states in the capacitor and a constant charge-relaxation resistance equal to half of the resistance quantum h/2e 2, when a single mode is transmitted between the capacitance and a reservoir. By applying a microwave excitation to a gate located on top of a coherent submicronic quantum dot that is coupled to a reservoir, we validate this theoretical prediction on the ac conductance of the quantum RC circuit. Our study demonstrates that the ac conductance is directly related to the dwell time of electrons in the capacitor. Thereby, we observed a counterintuitive behavior of a quantum origin: as the transmission of the single conducting mode decreases, the resistance of the quantum RC circuit remains constant while the capacitance oscillates. © 2012 IOP Publishing Ltd.

Mathy C.J.M.,Harvard - Smithsonian Center for Astrophysics | Mathy C.J.M.,Harvard University | Zvonarev M.B.,Harvard University | Zvonarev M.B.,University Paris - Sud | And 2 more authors.
Nature Physics | Year: 2012

Fast obstacles in a medium are responsible for striking physical phenomena, such as aerodynamic flutter, Čerenkov radiation and acoustic shock waves. In a hydrodynamic picture, quantum systems exhibit analogues of these dynamical features. Here we uncover novel quantum dynamics induced by fast particles by considering impurities injected supersonically into a one-dimensional quantum liquid. We find that the injected particle never comes to a full stop, at odds with conventional expectations of relaxation. Furthermore the system excites a new type of collective mode, manifesting itself in several observable quantities, such as long-lived oscillations in the velocity of the injected particle and simultaneous oscillations of the correlation hole formed around the impurity. These features are inherently quantum-mechanical and provide an example of a dynamically formed quantum coherent state propagating through a many-body environment while maintaining its coherence. The signatures of these effects can be probed directly with existing experimental tools. © 2012 Macmillan Publishers Limited. All rights reserved.

Pankrashkin K.,University Paris - Sud
Journal of Physics A: Mathematical and Theoretical | Year: 2010

The spectral problem on a periodic domain with cracks is studied. An asymptotic form of dispersion relations is calculated under the assumption that the opening of the cracks is small. © 2010 IOP Publishing Ltd.

Foyer C.H.,University of Leeds | Noctor G.,University Paris - Sud
Plant, Cell and Environment | Year: 2012

Light-driven redox chemistry is a powerful source of redox signals that has a decisive input into transcriptional control within the cell nucleus. Like photosynthetic electron transport pathways, the respiratory electron transport chain exerts a profound control over gene function, in order to balance energy (reductant and ATP) supply with demand, while preventing excessive over-reduction or over-oxidation that would be adversely affect metabolism. Photosynthetic and respiratory redox chemistries are not merely housekeeping processes but they exert a controlling influence over every aspect of plant biology, participating in the control of gene transcription and translation, post-translational modifications and the regulation of assimilatory reactions, assimilate partitioning and export. The number of processes influenced by redox controls and signals continues to increase as do the components that are recognized participants in the associated signalling pathways. A step change in our understanding of the overall importance of the cellular redox hub to plant cells has occurred in recent years as the complexity of the management of the cellular redox hub in relation to metabolic triggers and environmental cues has been elucidated. This special issue describes aspects of redox regulation and signalling at the cutting edge of current research in this dynamic and rapidly expanding field. © 2011 Blackwell Publishing Ltd.

Moller A.P.,University Paris - Sud | Mousseau T.A.,University of South Carolina
Biological Reviews | Year: 2013

Natural levels of radioactivity on the Earth vary by more than a thousand-fold; this spatial heterogeneity may suffice to create heterogeneous effects on physiology, mutation and selection. We review the literature on the relationship between variation in natural levels of radioactivity and evolution. First, we consider the effects of natural levels of radiation on mutations, DNA repair and genetics. A total of 46 studies with 373 effect size estimates revealed a small, but highly significant mean effect that was independent of adjustment for publication bias. Second, we found different mean effect sizes when studies were based on broad categories like physiology, immunology and disease frequency; mean weighted effect sizes were larger for studies of plants than animals, and larger in studies conducted in areas with higher levels of radiation. Third, these negative effects of radiation on mutations, immunology and life history are inconsistent with a general role of hormetic positive effects of radiation on living organisms. Fourth, we reviewed studies of radiation resistance among taxa. These studies suggest that current levels of natural radioactivity may affect mutational input and thereby the genetic constitution and composition of natural populations. Susceptibility to radiation varied among taxa, and several studies provided evidence of differences in susceptibility among populations or strains. Crucially, however, these studies are few and scattered, suggesting that a concerted effort to address this lack of research should be made. © 2012 The Authors. Biological Reviews © 2012 Cambridge Philosophical Society.

Ellwanger U.,University Paris - Sud
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2011

In the Next-to-Minimal Supersymmetric Standard Model, CP-even Higgs bosons can have masses in the range of 80-110 GeV in agreement with constraints from LEP due to their sizeable singlet component. Nevertheless their branching ratio into two photons can be more than 10 times larger than the one of a Standard Model Higgs boson of similar mass due to a reduced coupling to b quarks. This can lead to a spectacular enhancement of the Higgs signal rate in the di-photon channel at hadron colliders by a factor 6. Corresponding scenarios can occur in the Next-to-Minimal Supersymmetric Standard Model for a relatively low Susy breaking scale. © 2011 Elsevier B.V.

Moller A.P.,University Paris - Sud | Moller A.P.,Center for Advanced Study
Behavioral Ecology | Year: 2010

Many animals have successfully adapted to human proximity, with dramatic increases in abundance as a consequence. Although such transitions imply a fitness advantage, the fitness benefits of associations between animals and humans have not been thoroughly investigated. In a comparative study of nest predation, I compared predation rates in 6874 nests of 11 species of birds with sympatric populations breeding indoors and outdoors. Mean nest predation rates were 23.5% outdoors, but only 1.0% indoors, because corvid nest predators never entered buildings. There was a negative correlation between nest predation rate and the proportion of individuals breeding indoors, implying that as species became more adapted to humans, and hence breeding indoors became more frequent, there was a significant decrease in nesting failure that translated into a difference in reproductive success due to reductions in nest predation. Finally, the difference in predation rate between outdoor and indoor nests was related to time since urbanization and number of generations since urbanization, implying that initially there was a large selection differential followed by reduced fitness differences between birds breeding outdoors and indoors due to gradual adaptation to human proximity by reproducing birds. With a high intensity of natural selection, these findings suggest that such adaptation to human proximity may only take a few hundred generations, as shown by several species that have only recently become associated with humans. © 2010 The Author.

Ghashghaie J.,University Paris - Sud | Badeck F.W.,Italian Agricultural Research Council | Badeck F.W.,Potsdam Institute for Climate Impact Research
New Phytologist | Year: 2014

In general, leaves are 13C-depleted compared with all other organs (e.g. roots, stem/trunk and fruits). Different hypotheses are formulated in the literature to explain this difference. One of these states that CO2 respired by leaves in the dark is 13C-enriched compared with leaf organic matter, while it is 13C-depleted in the case of root respiration. The opposite respiratory fractionation between leaves and roots was invoked as an explanation for the widespread between-organ isotopic differences. After summarizing the basics of photosynthetic and post-photosynthetic discrimination, we mainly review the recent findings on the isotopic composition of CO2 respired by leaves (autotrophic organs) and roots (heterotrophic organs) compared with respective plant material (i.e. apparent respiratory fractionation) as well as its metabolic origin. The potential impact of such fractionation on the isotopic signal of organic matter (OM) is discussed. Some perspectives for future studies are also proposed. © 2013 New Phytologist Trust.

Clavel-Chapelon F.,University Paris - Sud
International Journal of Epidemiology | Year: 2015

The E3N (Etude Epidémiologique auprès de femmes de la Mutuelle Générale de l'Education Nationale) cohort was initiated in 1990 to investigate therisk factors associated with cancer and other major non-communicable diseases in women. The participants were insured through a national health system that primarily covered teachers, and were enrolled from 1990 after returning baseline self-administered questionnaires and providing informed consent. The cohort comprised nearly 100 000 women with baseline ages ranging from 40 to 65 years. Follow-up questionnaires were sent approximately every 2-3 years after the baseline and addressed general and lifestyle characteristics together with medical events (cancer, cardiovascular diseases, diabetes, depression, fractures and asthma, among others). The follow-up questionnaire response rate remained stable at approximately 80%. A biological material bank was generated and included blood samples collected from 25 000 women and saliva samples from an additional 47 000 women. Ageing among the E3N cohort provided the opportunity to investigate factors related to age-related diseases and conditions as well as disease survival. The new E4N complementary cohort (Epidemiology 4 kNowledge), which comprises the children and grandchildren of the E3N cohort as well as the children's fathers, will allow researchers to investigate key life periods during which exposures to environmental factors most strongly influence the later disease risk. The E3N and E4N cohort data will be used to investigate diseases and risk factors through a transgenerational approach. Requests for collaborations are welcome, particularly those in conjunction with rare diseases. © The Author 2014; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association.

We prepared high-density plasmonic nanostructures on a glass substrate. By using soft UV nanoimprint lithography, gold nanodisks with a diameter of 65 nm were obtained on an area of 1 mm2. We tested these gold nanosensors in the biotin/streptavidin system to study their selectivity and sensitivity of detection. The prepared gold nanodisks could detect streptavidin at 10 pM. © 2012 by the authors.

Servin A.L.,CNRS Biomolecules: Conception, Isolation, and Synthesis Laboratory | Servin A.L.,University Paris - Sud
Clinical Microbiology Reviews | Year: 2014

The pathogenicity and clinical pertinence of diffusely adhering Escherichia coli expressing the Afa/Dr adhesins (Afa/Dr DAEC) in urinary tract infections (UTIs) and pregnancy complications are well established. In contrast, the implication of intestinal Afa/Dr DAEC in diarrhea is still under debate. These strains are age de-pendently involved in diarrhea in children, are apparently not involved in diarrhea in adults, and can also be asymptomatic intestinal microbiota strainsin children and adult. This comprehensive review analyzes the epidemiology and diagnosis and highlights recent progress which has improved the understanding of Afa/Dr DAEC pathogenesis. Here,Isummarize the roles of Afa/Dr DAEC virulence factors, including Afa/Dr adhesins, flagella, Sat toxin, and pks island products, in the development of specific mechanisms of pathogenicity. In intestinal epithelial polarized cells, the Afa/Dr adhesins trigger cell membrane receptor clustering and activation of the linked cell signaling pathways, promote structural and functional cell lesions and injuries in intestinal barrier, induce proinflammatory responses, create angiogenesis, instigate epithelial-mesenchymal transition-like events, and lead to pks-dependent DNA damage. UTI-associated Afa/Dr DAEC strains, following adhesin-membrane receptor cell interactions and activation of associated lipid raft-dependent cell signaling pathways, internalize in a microtubule-dependent manner within urinary tract epithelial cells, develop a particular intracellular lifestyle, and trigger a toxin-dependent cell detachment. In response to Afa/Dr DAEC infection, the host epithelial cells generate antibacterial defense responses. Finally, I discuss a hypothetical role of intestinal Afa/Dr DAEC strains that can act as “silent pathogens” with the capacity to emerge as “pathobionts” for the development of inflammatory bowel disease and intestinal carcinogenesis. © 2014, American Society for Microbiology. All Rights Reserved.

Aubrun F.,University Claude Bernard Lyon 1 | Mazoit J.-X.,University Paris - Sud | Riou B.,University Pierre and Marie Curie
British Journal of Anaesthesia | Year: 2012

Relief of acute pain during the immediate postoperative period is an important task for anaesthetists. Morphine is widely used to control moderate-to-severe postoperative pain and the use of small i.v. boluses of morphine in the post-anaesthesia care unit allows a rapid titration of the dose needed for adequate pain relief. The essential principle of a titration regimen must be to adapt the morphine dose to the pain level. Although morphine would not appear to be the most appropriate choice for achieving rapid pain relief, this is the sole opioid assessed in many studies of immediate postoperative pain management using titration. More than 90 of the patients have pain relief using a protocol of morphine titration and the mean dose required to obtain pain relief is 12 (7) mg, after a median of four boluses. Sedation is frequent during i.v. morphine titration and should be considered as a morphine-related adverse event and not evidence of pain relief. The incidence of ventilatory depression is very low when the criteria to limit the dose of i.v. morphine are enforced. Morphine titration can be used with caution in elderly patients, in children, or in obese patients. In practice, i.v. morphine titration allows the physician to meet the needs of individual patients rapidly and limits the risk of overdose making this method the first step in postoperative pain management. © The Author [2012]. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved.

Ben-Abdallah P.,University Paris - Sud | Biehs S.-A.,Carl von Ossietzky University
Applied Physics Letters | Year: 2013

A thermal diode transports heat mainly in one preferential direction rather than in the opposite direction. This behavior is generally due to the non-linear dependence of certain physical properties with respect to the temperature. Here we introduce a radiative thermal diode which rectifies heat transport thanks to the phase transitions of materials. Rectification coefficients greater than 70% and up to 90% are shown, even for small temperature differences. This result could have important applications in the development of future contactless thermal circuits or in the conception of radiative coatings for thermal management. © 2013 AIP Publishing LLC.

Caillol J.-M.,University Paris - Sud | Caillol J.-M.,French National Center for Scientific Research
Nuclear Physics B | Year: 2012

We study some analytical properties of the solutions of the non-perturbative renormalization group flow equations for a scalar field theory with Z2 symmetry in the ordered phase, i.e. at temperatures below the critical temperature. The study is made in the framework of the local potential approximation. We show that the required physical discontinuity of the magnetic susceptibility χ(M) at M=±M0 (M0 spontaneous magnetization) is reproduced only if the cut-off function which separates high and low energy modes satisfies to some restrictive explicit mathematical conditions; we stress that these conditions are not satisfied by a sharp cut-off in dimensions of space d<4.By generalizing a method proposed earlier by Bonanno and Lacagnina [Nucl. Phys. B 693 (2004) 36] to any kind of cut-off we propose to solve numerically the renormalization group flow equations for the threshold functions rather than for the local potential. It yields an algorithm sufficiently robust and precise to extract universal as well as non-universal quantities from numerical experiments at any temperature, in particular at sub-critical temperatures in the ordered phase. Numerical results obtained for the φ4 potential with three different cut-off functions are reported and compared. The data confirm our theoretical predictions concerning the analytical behavior of χ(M) at M=±M0.Fixed point solutions of the adimensioned renormalization group flow equations are also obtained in the same vein, that is by solving the fixed points equations and the associated eigenvalue problem for the threshold functions rather than for the potential. We report high precision data for the odd and even spectra of critical exponents for different cut-offs obtained in this way. © 2011 Elsevier B.V..

Felden B.,French Institute of Health and Medical Research | Vandenesch F.,University of Lyon | Bouloc P.,University Paris - Sud | Romby P.,University of Strasbourg
PLoS Pathogens | Year: 2011

Staphylococcus aureus is a major human pathogen causing a wide spectrum of nosocomial and community-associated infections with high morbidity and mortality. S. aureus generates a large number of virulence factors whose timing and expression levels are precisely tuned by regulatory proteins and RNAs. The aptitude of bacteria to use RNAs to rapidly modify gene expression, including virulence factors in response to stress or environmental changes, and to survive in a host is an evolving concept. Here, we focus on the recently inventoried S. aureus regulatory RNAs, with emphasis on those with identified functions, two of which are directly involved in pathogenicity. © 2011 Felden et al.

Xing M.,Johns Hopkins University | Haugen B.R.,Aurora University | Schlumberger M.,University Paris - Sud
The Lancet | Year: 2013

Substantial developments have occurred in the past 5-10 years in clinical translational research of thyroid cancer. Diagnostic molecular markers, such as RET-PTC, RAS, and BRAFV600E mutations; galectin 3; and a new gene expression classifier, are outstanding examples that have improved diagnosis of thyroid nodules. BRAF mutation is a prognostic genetic marker that has improved risk stratification and hence tailored management of patients with thyroid cancer, including those with conventionally low risks. Novel molecular-targeted treatments hold great promise for radioiodine-refractory and surgically inoperable thyroid cancers as shown in clinical trials; such treatments are likely to become a component of the standard treatment regimen for patients with thyroid cancer in the near future. These novel molecular-based management strategies for thyroid nodules and thyroid cancer are the most exciting developments in this unprecedented era of molecular thyroid-cancer medicine.

Dreiner H.K.,University of Bonn | Staub F.,University of Bonn | Vicente A.,University Paris - Sud
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

We study the possible LHC collider signatures in the next-to-minimal supersymmetric standard model. The general next-to-minimal supersymmetric standard model consists of 29 supersymmetric particles which can be mass ordered in 29!9×1030 ways. To reduce the number of hierarchies to a more manageable amount we assume a degeneracy of the sfermions of the first two generations with the same quantum numbers. Further assumptions about the neutralino and chargino masses leave 15 unrelated parameters. We check all 15!≈1012 relevant mass orderings for the dominant decay chains and the corresponding collider signatures at the LHC. As preferred signatures, we consider charged leptons, missing transverse momentum, jets, and W, Z or Higgs bosons. We present the results for three different choices of the singlet to Higgs coupling λ: (a) small, O(λ)O(Ytop). We compare these three scenarios with the MSSM expectations as well as among each other. We also mention a possible mass hierarchy leading to seven jets plus one lepton signatures at the LHC and comment briefly on the consequence of possible R-parity violation. © 2013 American Physical Society.

Matveenko S.I.,University Paris - Sud
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2010

We found an analytical solution for the vortex structure in a rapidly rotating trapped Bose-Einstein condensate in the lowest Landau level approximation. This solution is exact in the limit of a large number of vortices and is obtained for the case of a condensate in a anisotropic harmonic potential. The solution describes as limiting cases both a triangle vortex lattice in the symmetric potential trap and a quasi-one-dimensional structure of vortex rows in an asymmetric case, when the rotation frequency is very close to the lower trapping potential frequency. The shape of the density profile is found to be close to the Thomas-Fermi inverted paraboloid form, except in the vicinity of edges of a condensate cloud. © 2010 The American Physical Society.

Flower D.R.,Durham University | Pineau des Forets G.,University Paris - Sud | Pineau des Forets G.,Paris Observatory
Monthly Notices of the Royal Astronomical Society | Year: 2012

We have developed further the technique of time-dependent modelling of magnetohydrodynamic shock waves, with a view to interpreting the molecular line emission from outflow sources. The extensively observed source L1157 B1 was chosen as an exemplar of the application of this technique. The dynamical age of the shock wave model was varied in the range 500 ≤t≤ 5000yr, with the best fit to the observed line intensities being obtained for t= 1000yr; this is of the same order as the dynamical age derived by Gueth, Guilloteau & Bachiller from their observations of L1157 B1. The emission line spectra of H 2, CO, SiO, ortho- and para-H 2O, ortho- and para-NH 3, and A- and E-type CH 3OH were calculated in parallel with the dynamical and chemical parameters of the model, using the 'large velocity gradient' (LVG) approximation to the line transfer problem. We compared the predictions of the models with the observed intensities of emission lines of H 2, CO, SiO, ortho-H 2O, ortho-NH 3 and CH 3OH, which include recent Herschel satellite measurements. In the case of SiO, we show (in Appendix A) that extrapolations of the collisional rate coefficients beyond the range of kinetic temperature for which they were originally calculated lead to spurious rotational line intensities and profiles. The computed emission-line spectra of SiO, NH 3 and CH 3OH are shown to depend on the assumed initial composition of the grain mantles, from whence they are released, by sputtering in the shock wave, into the gas phase. The dependence of the model predictions on the adopted form of the grain-size distribution is investigated in Appendix B; the corresponding integral line intensities are given in tabular form, for a range of C-type shock speeds, in the online Supporting Information. © 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS.

Goudail F.,University Paris - Sud
Optics Letters | Year: 2010

We compare the performances of three different Polarimetric imaging modalities, scalar, Stokes, and Mueller, in terms of achievable contrast for target detection applications. These modalities require, respectively, 1, 4, and 16 intensity measurements to form the Polarimetrie image. We show that the technique that leads to the best contrast is the scalar one, which requires only one optimized measurement. © 2010 Optical Society of America.

Babichev E.,University Paris - Sud | Deffayet C.,University of Paris Pantheon Sorbonne | Deffayet C.,Paris West University Nanterre La Defense
Classical and Quantum Gravity | Year: 2013

We introduce the Vainshtein mechanism which plays a crucial role in massive gravities, as well as in related theories such as Galileons and their extensions. This mechanism, also known as k-mouflage, allows to hide via nonlinear effects - typically for source distances smaller than a so-called Vainshtein radius which depends on the source and on the theory considered - some degrees of freedom whose effects are then only left important at large distances, e.g. for cosmology. It is introduced here in nonlinear Fierz-Pauli theories (massive gravities), including the dRGT theories, in their decoupling limits, as well as in other models such as the DGP model or generalized Galileons. This presentation is self-contained, and before discussing the Vainshtein mechanism we introduce some useful results and concepts concerning massive gravity, such as the vDVZ discontinuity, the decoupling limits or the Boulware-Deser ghost. © 2013 IOP Publishing Ltd.

Lansberg J.P.,University Paris - Sud
Nuclear Physics A | Year: 2013

I discuss Υ{hooked} production in pp collisions at RHIC, Tevatron and LHC energies, in particular the behaviour of the differential cross section in rapidity and the impact of QCD corrections on the P T differential cross section. I also emphasise the very good agreement between the parameter-free predictions of the Colour-Singlet Model (CSM) and the first LHC data, especially in the region of low transverse momenta, which is the most relevant one for heavy-ion studies. I also show that the CSM predicts Υ{hooked} cross-section ratios in agreement with the most recent LHC data. I then briefly discuss the nuclear-matter effects on Υ{hooked} production at RHIC and the LHC in p(d)A collisions and, by extension, in AA collisions. I argue that a) the Υ{hooked} break-up probability can be neglected, at RHIC and the LHC, b) gluon shadowing -although non-negligible- is not strong enough to describe forward RHIC data, c) backward RHIC data hints at a gluon EMC effect, possibly stronger than the quark one. Outlooks for the LHC pPb run are also presented. © 2012 Elsevier B.V.

Thuery P.,CEA Saclay Nuclear Research Center | Riviere E.,University Paris - Sud
Dalton Transactions | Year: 2013

Five oxalate complexes containing both uranyl and copper(ii) ions and 2,2′-bipyridine (bipy), 2,2′-bipyrimidine (bipym) or 1,10-phenanthroline (phen) as co-ligands have been synthesized under hydrothermal conditions and their crystal structures were determined. [UO 2Cu(C2O4)(NO3)2(bipy) (H2O)] (1) is a molecular complex in which the two cations are connected by the bis-chelating oxalate. A one-dimensional uranyl oxalate ribbon is formed in [UO2Cu(C2O4)2(bipym) (H2O)] (2), with uranyl ions bound to two chelating anions and to a third, monodentate oxalate which holds the decorating [Cu(bipym)(H 2O)]2+ groups. Complex [(UO2) 2Cu2(C2O4)2(bipym) 3(OH)2]·2NO3 (3) is a two-dimensional assembly in which uranyl oxalate chains are linked to one another by [Cu 2(bipym)3]4+ dinuclear units through bridging hydroxide ions. Finally, [UO2Cu(C2O4) 2(bipy)] (4) and [UO2Cu(C2O4) 2(phen)] (5) display identical three-dimensional arrangements containing uranyl oxalate sheets connected to one another by copper oxalate dinuclear units. The magnetic properties of compounds 2 and 4 have been investigated. Weak inter-chain antiferromagnetic interactions between copper(ii) atoms are present in 2, while 4 displays strong oxalate-mediated antiferromagnetic exchange (J = -335 cm-1). These complexes are the first uranyl-d block metal oxalate complexes to be reported. © 2013 The Royal Society of Chemistry.

Noel V.,French National Center for Scientific Research | Chepfer H.,University Paris - Sud
Journal of Geophysical Research: Atmospheres | Year: 2010

We analyze optical signatures in 18 months of CALIOP layer-integrated backscatter and depolarization ratio to investigate the geographical and seasonal distribution of oriented crystals in ice clouds on a global scale. Oriented crystals are found to be rare: they appear in ∼6% of all ice cloud layers, and inside these layers the proportion of oriented crystals is estimated below 5%, even though they have a significant effect on the cloud optical properties. The geographical pattern of crystal orientation is very stable over the year, without any noticeable cycle. We investigate the atmospheric conditions which might lead to crystal orientation, including synoptic-scale dynamics and thermodynamic profiles. In the tropics, detections of crystal orientation are more numerous in areas dominated by convection on a monthly basis, and at midlatitudes less numerous in areas dominated by strong horizontal winds. Synoptic effects, however, appear secondary; orientation is primarily driven by temperature. Oriented crystals are mostly nonexistent in ice clouds colder than -30°C, and very frequent in warmer ice clouds, appearing in 30% of such clouds in the tropics and up to 50% at higher latitudes. The temperatures where oriented crystals are found (-30°C to -10°C) are conducive to the formation of planar crystals. Results suggest oriented crystals are more frequent just above cloud base in slightly thicker cloud layers, which might provide clues to how and why orientation takes place. Copyright 2010 by the American Geophysical Union.

Bonzom V.,Perimeter Institute for Theoretical Physics | Gurau R.,Perimeter Institute for Theoretical Physics | Rivasseau V.,University Paris - Sud
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2012

We study analytically the Ising model coupled to random lattices in dimension three and higher. The family of random lattices we use is generated by the large N limit of a colored tensor model generalizing the two-matrix model for Ising spins on random surfaces. We show that, in the continuum limit, the spin system does not exhibit a phase transition at finite temperature, in agreement with numerical investigations. Furthermore we outline a general method to study critical behavior in colored tensor models. © 2012 Elsevier B.V.

Djouadi A.,University Paris - Sud | Djouadi A.,CERN | Lenz A.,CERN
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2012

The search for the effects of heavy fermions in the extension of the Standard Model with a fourth generation is part of the experimental program of the Tevatron and LHC experiments. Besides being directly produced, these states affect drastically the production and decay properties of the Higgs boson. In this Letter, we first reemphasize the known fact that in the case of a light and long-lived fourth neutrino, the present collider searches do not permit to exclude a Higgs boson with a mass below the WW threshold. In a second step, we show that the recent results from the ATLAS and CMS Collaborations which observe an excess in the γγ and 4ℓ ± search channels corresponding to a Higgs boson with a mass M H≈125 GeV, cannot rule out the fourth generation possibility if the H→γγ decay rate is evaluated when naively implementing the leading O(GFmf'2) electroweak corrections. Including the exact next-to-leading order electroweak corrections leads to a strong suppression of the H→γγ rate and makes this channel unobservable with present data. Finally, we point out that the observation by the Tevatron Collaborations of a ≳2σ excess in the mass range M H=115-135 GeV in the channel qq-→WH→Wbb- can definitely not be accommodated by the fourth generation fermion scenario. All in all, if the excesses observed at the LHC and the Tevatron are indeed due to a Higgs boson, they unambiguously exclude the perturbative fermionic fourth generation case. In passing, we also point out that the Tevatron excess definitely rules out the fermiophobic Higgs scenario as well as scenarios in which the Higgs couplings to gauge bosons and bottom quarks are significantly reduced. © 2012 Elsevier B.V.

Forterre P.,University Paris - Sud
Origins of Life and Evolution of Biospheres | Year: 2010

Are viruses alive? Until very recently, answering this question was often negative and viruses were not considered in discussions on the origin and definition of life. This situation is rapidly changing, following several discoveries that have modified our vision of viruses. It has been recognized that viruses have played (and still play) a major innovative role in the evolution of cellular organisms. New definitions of viruses have been proposed and their position in the universal tree of life is actively discussed. Viruses are no more confused with their virions, but can be viewed as complex living entities that transform the infected cell into a novel organism-the virus-producing virions. I suggest here to define life (an historical process) as the mode of existence of ribosome encoding organisms (cells) and capsid encoding organisms (viruses) and their ancestors. I propose to define an organism as an ensemble of integrated organs (molecular or cellular) producing individuals evolving through natural selection. The origin of life on our planet would correspond to the establishment of the first organism corresponding to this definition. © The Author(s) 2010.

Malartre M.,University Paris - Sud
Cellular and Molecular Life Sciences | Year: 2016

EGFR signalling is a well-conserved signalling pathway playing major roles during development and cancers. This review explores what studying the EGFR pathway during Drosophila eye development has taught us in terms of the diversity of its regulatory mechanisms. This model system has allowed the identification of numerous positive and negative regulators acting at specific time and place, thus participating to the tight control of signalling. EGFR signalling regulation is achieved by a variety of mechanisms, including the control of ligand processing, the availability of the receptor itself and the transduction of the cascade in the cytoplasm. Ultimately, the transcriptional responses contribute to the establishment of positive and negative feedback loops. The combination of these multiple mechanisms employed to regulate the EGFR pathway leads to specific cellular outcomes involved in functions as diverse as the acquisition of cell fate, proliferation, survival, adherens junction remodelling and morphogenesis. © 2016 Springer International Publishing

Bourdel T.,University Paris - Sud
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2012

We study superfluid transitions in bidimensional (2D) and tridimensional (3D) disordered and interacting Bose gases. We work in the limit of long-range correlated disorder such that it can be treated in the local density approximation. We present superfluid transition curves in both the disorder-temperature plane and the disorder-entropy plane in 2D and 3D Bose gases. Surprisingly, we find that a small amount of disorder is always favorable to the apparition of a superfluid. Our results offer a quantitative comparison with recent experiments in 2D disordered ultracold gases, for which no exact theory exists. © 2012 American Physical Society.

Rullier-Albenque F.,CEA Saclay Nuclear Research Center | Colson D.,CEA Saclay Nuclear Research Center | Forget A.,CEA Saclay Nuclear Research Center | Alloul H.,University Paris - Sud
Physical Review Letters | Year: 2012

The resistivity, Hall effect, and transverse magnetoresistance have been measured in low residual resistivity single crystals of LiFeAs. A comparison with angle resolved photoemission spectroscopy and quantum oscillation data implies that four carrier bands unevenly contribute to the transport. However the scattering rates of the carriers all display the T2 behavior expected for a Fermi liquid. Near T c low field deviations of the magnetoresistance with respect to a H2 variation permit us to extract the superconducting fluctuation contribution to the conductivity. Though below T c the anisotropy of superconductivity is rather small, the superconducting fluctuation displays a quasi-ideal two-dimensional behavior which persists up to 1.4 T c. These results call for a refined theoretical understanding of the multiband behavior of superconductivity in this pnictide. © 2012 American Physical Society.

Berret B.,University Paris - Sud | Jean F.,ParisTech UniversiteParis Saclay
Journal of Neuroscience | Year: 2016

To want something now rather than later is a common attitude that reflects the brain’s tendency to value the passage of time. Because the time taken to accomplish an action inevitably delays task achievement and reward acquisition, this idea was ported to neural movement control within the “cost of time” theory. This theory provides a normative framework to account for the underpinnings of movement time formation within the brain and the origin of a self-selected pace inhumanand animal motion. Then,howdoes the brain exactly value time in the control of action? To tackle this issue, we used an inverse optimal control approach and developed a general methodology allowing to squarely sample infinitesimal values of the time cost from experimental motion data. The cost of time underlying saccades was found to have a concave growth, thereby confirming previous results on hyperbolic reward discounting, yet without making any prior assumption about this hypothetical nature. For self-paced reaching, however, movement time was primarily valued according to a striking sigmoidal shape; its rate of change consistently presented a steep rise before a maximum was reached and a slower decay was observed. Theoretical properties of uniqueness and robustness of the inferred time cost were established for the class of problems under investigation, thus reinforcing the significance of the present findings. These results may offer a unique opportunity to uncover how the brain values the passage of time in healthy and pathological motor control and shed new light on the processes underlying action invigoration. © 2016 the authors.

Sicard D.,University Paris - Sud | Legras J.-L.,French National Institute for Agricultural Research
Comptes Rendus - Biologies | Year: 2011

Yeasts of the Saccharomyces sensu stricto species complex are able to convert sugar into ethanol and CO2 via fermentation. They have been used for thousands years by mankind for fermenting food and beverages. In the Neolithic times, fermentations were probably initiated by naturally occurring yeasts, and it is unknown when humans started to consciously add selected yeast to make beer, wine or bread. Interestingly, such human activities gave rise to the creation of new species in the Saccharomyces sensu stricto complex by interspecies hybridization or polyploidization. Within the S. cerevisiae species, they have led to the differentiation of genetically distinct groups according to the food process origin. Although the evolutionary history of wine yeast populations has been well described, the histories of other domesticated yeasts need further investigation. © 2011 Académie des sciences.

Cozza A.,University Paris - Sud
IEEE Transactions on Electromagnetic Compatibility | Year: 2012

Results from random-matrix theory are applied to the modeling of random fluctuations in the modal density observed in an electrically large cavity. By starting from results describing the probability distribution of the modal spacing between adjacent frequencies of resonance, or nearest-neighbor spacing, we introduce a simple procedure allowing to pass from the modal spacing to the local modal density as measured over a finite bandwidth. This local definition of the modal density is more consistent with the physics of reverberation chambers, since it has been recently shown that the deviation from asymptotic statistics of field samples is dependent on the number of modes overlapping within a modal bandwidth. It is shown that as opposed to current interpretation, the number of overlapping modes is a strongly fluctuating quantity, and that estimating it by taking the frequency derivative of Weyls formula can lead to nonnegligible errors and misunderstandings. Regarding these fluctuations as second-order effects is, therefore, not sound from a physical point of view, since the existence of modal-depleted scenarios can easily explain the appearance of local anomalies in the field statistics, particularly, but not exclusively, in the lower frequency range of operation of reverberation chambers. © 1964-2012 IEEE.

Ribe N.M.,University Paris - Sud
Journal of Fluid Mechanics | Year: 2012

Buckling instabilities of thin sheets or plates of viscous fluid occur in situations ranging from food and polymer processing to geology. Slim, Teichman & Mahadevan (J. Fluid Mech., this issue, vol. 694, 2012, pp. 5-28) study numerically the buckling of a sheared viscous plate floating on a denser fluid using three approaches: a classical 'thin viscous plate' model; full numerical solution of the three-dimensional Stokes equations; and a novel 'advection-augmented' thin-plate model that accounts (in an asymptotically inconsistent way) for the advection of perturbations by the background shear flow. The advection-augmented thin-plate model is markedly superior to the classical one in its ability to reproduce the predictions of the Stokes solution, illustrating the utility of judicious violations of asymptotic consistency in fluid-mechanical models. © 2012 Cambridge University Press.

Wallet J.-C.,University Paris - Sud
Nuclear Physics B | Year: 2016

The noncommutative space Rλ3, a deformation of R3, supports a 3-parameter family of gauge theory models with gauge-invariant harmonic term, stable vacuum and which are perturbatively finite to all orders. Properties of this family are discussed. The partition function factorizes as an infinite product of reduced partition functions, each one corresponding to the reduced gauge theory on one of the fuzzy spheres entering the decomposition of Rλ3. For a particular sub-family of gauge theories, each reduced partition function is exactly expressible as a ratio of determinants. A relation with integrable 2-D Toda lattice hierarchy is indicated. © 2016 The Author.

Dubois-Violette M.,University Paris - Sud
Nuclear Physics B | Year: 2016

Based on an interpretation of the quark-lepton symmetry in terms of the unimodularity of the color group SU(3) and on the existence of 3 generations, we develop an argumentation suggesting that the "finite quantum space" corresponding to the exceptional real Jordan algebra of dimension 27 (the Euclidean Albert algebra) is relevant for the description of internal spaces in the theory of particles. In particular, the triality which corresponds to the 3 off-diagonal octonionic elements of the exceptional algebra is associated to the 3 generations of the Standard Model while the representation of the octonions as a complex 4-dimensional space C⊕C3 is associated to the quark-lepton symmetry (one complex for the lepton and 3 for the corresponding quark). More generally it is suggested that the replacement of the algebra of real functions on spacetime by the algebra of functions on spacetime with values in a finite-dimensional Euclidean Jordan algebra which plays the role of "the algebra of real functions" on the corresponding almost classical quantum spacetime is relevant in particle physics. This leads us to study the theory of Jordan modules and to develop the differential calculus over Jordan algebras (i.e. to introduce the appropriate notion of differential forms). We formulate the corresponding definition of connections on Jordan modules. © 2016 The Author.

Mitropoulos D.,National and Kapodistrian University of Athens | Artibani W.,University of Verona | Graefen M.,University of Hamburg | Remzi M.,Landesklinikum Korneuburg | And 2 more authors.
European Urology | Year: 2012

Context: The incidence of postoperative complications is still the most frequently used surrogate marker of quality in surgery, but no standard guidelines or criteria exist for reporting surgical complications in the area of urology. Objective: To review the available reporting systems used for urologic surgical complications, to establish a possible change in attitude towards reporting of complications using standardised systems, to assess systematically the Clavien-Dindo system when used for the reporting of complications related to urologic surgical procedures, to identify shortcomings in reporting complications, and to propose recommendations for the development and implementation of future reporting systems that are focused on patient-centred outcomes. Evidence acquisition: Standardised systems for reporting and classification of surgical complications were identified through a systematic review of the literature. To establish a possible change in attitude towards reporting of complications related to urologic procedures, we performed a systematic literature search of all papers reporting complications after urologic surgery published in European Urology, Journal of Urology, Urology, BJU International, and World Journal of Urology in 1999-2000 and 2009-2010. Data identification for the systematic assessment of the Clavien-Dindo system currently used for the reporting of complications related to urologic surgical interventions involved a Medline/Embase search and the search engines of individual urologic journals and publishers using Clavien, urology, and complications as keywords. All selected papers were full-text retrieved and assessed; analysis was done based on structured forms. Evidence synthesis: The systematic review of the literature for standardised systems used for reporting and classification of surgical complications revealed five such systems. As far as the attitude of urologists towards reporting of complications, a shift could be seen in the number of studies using most of the Martin criteria, as well as in the number of studies using either standardised criteria or the Clavien-Dindo system. The latter system was not properly used in 72 papers (35.3%). Conclusions: Uniformed reporting of complications after urologic procedures will aid all those involved in patient care and scientific publishing (authors, reviewers, and editors). It will also contribute to the improvement of the scientific quality of papers published in the field of urologic surgery. When reporting the outcomes of urologic procedures, the committee proposes a series of quality criteria. © 2011 European Association of Urology. Published by Elsevier B.V. All rights reserved.

Lamari F.D.,University of Paris 13 | Levesque D.,University Paris - Sud
Carbon | Year: 2011

The hydrogen adsorption on basal graphite planes functionalized by hydrogen atoms is studied by molecular modeling and numerical simulation at temperatures of 77 K and 293 K up to high pressure. At 77 K and pressure of 1 MPa, on such an adsorbing surface, the excess hydrogen physisorption is estimated equal to ∼ 7:0 wt%. At 293 K and 30 MPa, the excess physisorption reaches ∼ 1:5 wt%. A comparison between the hydrogen adsorption properties of functionalized graphite basal planes and plain graphite basal planes is presented for materials exhibiting similar porosities. © 2011 Published by Elsevier Ltd.

Moller A.P.,University Paris - Sud | Moller A.P.,Center for Advanced Study
Behavioral Ecology | Year: 2010

Urbanization and domestication share features in terms of characters that are favored by selection. These include loss of fear of humans, reduced corticosterone levels, prolonged breeding seasons, and several others. Here, I test the hypothesis that urbanization results from differential colonization of urban areas by species with heterogeneous levels of fear in the ancestral rural populations, followed by a reduction in variance in fear responses with a subsequent increase in diversity of fear responses as urban populations become adapted to the urban environment. Using information on variance in flight initiation distances (FIDs) when approached by a human, I show that rural populations of birds characterized by short mean flight distances and large variances in flight distances differentially colonized urban areas. As a consequence of this urban invasion, urban populations lost variation in FID. The variance in FID was initially larger in rural than in urban populations but eventually became larger in urban populations with time since urbanization. This secondary increase in variance in FID of urban populations was associated with an increase in population density of urban populations, suggesting that as birds became adapted to urban areas, they secondarily gained variance in behavioral flexibility.

Psimaras D.,French Institute of Health and Medical Research | Carpentier A.F.,University Paris - Sud | Rossi C.,Laboratory of Clinical Epidemiology
Journal of Neurology, Neurosurgery and Psychiatry | Year: 2010

Objective: Paraneoplastic neurological syndromes (PNS) probably result from an immune reaction against antigens shared by the nervous system and tumour cells. To characterise CSF alterations in these syndromes, we studied a large series of paraneoplastic patients. Methods: Using the PNS European database which includes patients diagnosed with PNS in Europe, we reviewed the clinical data of all patients included between 2000 and 2007 for which information on CSF was available. Patients were studied if they met the following inclusions criteria: (1) definite paraneoplastic disease with anti-Hu, anti-Yo, anti-CV2, anti-Ri anti-Ma/Ta and anti-Tr antibodies; (2) clinical information available; and (3) at least one CSF study. Results: 295 patients met the inclusion criteria. Abnormal CSF (pleiocytosis and/or high protein level and/ or oligoclonal bands) was found in 93% of patients. Pleiocytosis, but not hyperproteinorachia, was more frequently seen in patients in whom the CSF study was done early in the evolution. In 24 patients, oligoclonal bands were the only abnormality found in the CSF (10%). Elevated numbers of cells were found in 47% of patients before the third month compared with 28% after the third month (p<0.01). This evolution might suggest a subacute inflammation phase within the nervous system, followed by a non-inflammatory phase. The inflammation profile was similar in all antibody types, cancers or neurological syndromes of the PNS. Surprisingly, anti-Hu patients with high pleiocytosis at the time of diagnostic had a better survival in this study than those without pleiocytosis (572 days vs 365 days; p = 0.05). Conclusion: CSF inflammation is a common finding in PNS patients and can be a helpful tool for diagnosis, especially if this analysis is done within 3 months after neurological onset.

Hamai A.,University Paris - Sud
Science signaling | Year: 2012

Macroautophagy is an evolutionarily conserved homeostatic process that mediates the degradation of long-lived cytoplasmic components in eukaryotes, which allows cells to survive stresses such as inflammation, hypoxia, and deprivation of nutrients or growth factors. At least 30 members of the Atg (autophagy-related) protein family orchestrate this degradative process. Additional complexity resides in the signaling networks controlling the autophagic process, which include various posttranslational modifications of key components. Evidence is accumulating that protein acetylation represents an evolutionarily conserved mechanism tightly regulating macroautophagy.

Grasso M.,University Paris - Sud
Physical Review C - Nuclear Physics | Year: 2013

We examine Cr isotopes at the drip line, where surface effects related to the existence of a weakly bound s1/2 state are known to be important and tightly connected with the pairing phenomenon (antihalo effect). For these weakly bound isotopes, we evaluate the ground state to ground state two-neutron transfer probabilities within a mean-field-based approach. An important part of the discussion is devoted to the analysis of several procedures that can be employed to constrain the parameters of a phenomenological pairing interaction. The parameters are first adjusted to reproduce the experimental gaps evaluated with the five-point formula. This choice has, however, some consequences on the evolution of the pairing correlations along the isotopic chains and, in particular, at shell closures. Other procedures are then followed (adjustment on a theoretical pairing gap at mid-shell and on the two-neutron separation energies). For the transfer probabilities, we discuss the effects associated with different choices of the spatial localization of the pairing interaction. We indicate that the analysis of pair-transfer reactions for such cases (where the last bound state is a low-l state in a weakly bound nucleus) may improve our understanding of two aspects: the spatial distribution of pairing correlations in nuclei and the general problem of the persistence of pairing at the drip lines. © 2013 American Physical Society.

Ghofrani H.-A.,University of Marburg | Humbert M.,University Paris - Sud
European Respiratory Review | Year: 2014

Pulmonary arterial hypertension (PAH) is a complex, progressive disease with several pathobiological mechanisms, including the endothelin, nitric oxide and prostacyclin pathways. Current treatments for PAH target one of these pathways and, in more severe cases or instances of disease worsening, may be combined with a view to target multiple pathways in parallel. Treatment combination is performed sequentially (as an intensification from initial monotherapy) or upfront (use of two or more therapies in treatment-naı¨ve patients). Whilst combination therapy has been historically considered to be an option for the treatment of PAH, supporting evidence was typically limited to expert opinion, clinical experience and registry data.Data from randomised controlled trials on sequential combination therapy in particular has grown in recent years, resulting in a change in the level of recommendations in the latest update to the PAH treatment algorithm. However, short-term trials have shown inconsistent results, and have not been powered to assess morbidity/mortality outcomes. More recent data from long-term trials suggest a potential clinical benefit associated with sequential combination therapy.In this review we will introduce the concept of combination therapy, consider the latest evidence for both sequential and upfront combination therapy, and discuss additional considerations when initiating combination therapy in clinical practice. © ERS 2014.

Bellec M.,CNRS Condensed Matter Physics Laboratory | Kuhl U.,CNRS Condensed Matter Physics Laboratory | Montambaux G.,University Paris - Sud | Mortessagne F.,CNRS Condensed Matter Physics Laboratory
Physical Review Letters | Year: 2013

By means of a microwave tight-binding analogue experiment of a graphenelike lattice, we observe a topological transition between a phase with a pointlike band gap characteristic of massless Dirac fermions and a gapped phase. By applying a controlled anisotropy on the structure, we investigate the transition directly via density of states measurements. The wave function associated with each eigenvalue is mapped and reveals new states at the Dirac point, localized on the armchair edges. We find that with increasing anisotropy, these new states are more and more localized at the edges. © 2013 American Physical Society.

Richard-Miceli C.,University Paris - Sud | Criswell L.A.,University of California at San Francisco
Genome Medicine | Year: 2012

Most of the recently identified autoimmunity loci are shared among multiple autoimmune diseases. The pattern of genetic association with autoimmune phenotypes varies, suggesting that certain subgroups of autoimmune diseases are likely to share etiological similarities and underlying mechanisms of disease. In this review, we summarize the major findings from recent studies that have sought to refine genotype-phenotype associations in autoimmune disease by identifying both shared and distinct autoimmunity loci. More specifically, we focus on information from recent genome-wide association studies of rheumatoid arthritis, ankylosing spondylitis, celiac disease, multiple sclerosis, systemic lupus erythematosus, type 1 diabetes and inflammatory bowel disease. Additional work in this area is warranted given both the opportunity it provides to elucidate pathogenic mechanisms in autoimmunity and its potential to inform the development of improved diagnostic and therapeutic tools for this group on complex human disorders. © 2012 BioMed Central Ltd.

Leverrier A.,ICFO - Institute of Photonic Sciences | Grangier P.,University Paris - Sud
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2011

In this paper, we consider continuous-variable quantum-key-distribution (QKD) protocols which use non-Gaussian modulations. These specific modulation schemes are compatible with very efficient error-correction procedures, hence allowing the protocols to outperform previous protocols in terms of achievable range. In their simplest implementation, these protocols are secure for any linear quantum channels (hence against Gaussian attacks). We also show how the use of decoy states makes the protocols secure against arbitrary collective attacks, which implies their unconditional security in the asymptotic limit. © 2011 American Physical Society.

Djouadi A.,University Paris - Sud | Godbole R.M.,Indian Institute of Science | Mellado B.,University of Wisconsin - Madison | Mellado B.,University of Witwatersrand | Mohan K.,Indian Institute of Science
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2013

Determining the spin and the parity quantum numbers of the recently discovered Higgs-like boson at the LHC is a matter of great importance. In this Letter, we consider the possibility of using the kinematics of the tagging jets in Higgs production via the vector boson fusion (VBF) process to test the tensor structure of the Higgs-vector boson (HVV) interaction and to determine the spin and CP properties of the observed resonance. We show that an anomalous HVV vertex, in particular its explicit momentum dependence, drastically affects the rapidity between the two scattered quarks and their transverse momenta and, hence, the acceptance of the kinematical cuts that allow to select the VBF topology. The sensitivity of these observables to different spin-parity assignments, including the dependence on the LHC center of mass energy, are evaluated. In addition, we show that in associated Higgs production with a vector boson some kinematical variables, such as the invariant mass of the system and the transverse momenta of the two bosons and their separation in rapidity, are also sensitive to the spin-parity assignments of the Higgs-like boson. © 2013 Elsevier B.V.

Mauger J.-P.,French Institute of Health and Medical Research | Mauger J.-P.,University Paris - Sud
Biology of the Cell | Year: 2012

The endoplasmic reticulum (ER) is the major Ca2+ store inside the cell. Its organisation in specialised subdomains allows the local delivery of Ca2+ to specific cell areas on stimulation. The nuclear envelope (NE), which is continuous with the ER, has a double role: it insulates the nucleoplasm from the cytoplasm and it stores Ca2+ around the nucleus. Furthermore, all the constituents of the signalling cascade leading to Ca2+ mobilisation are found in the NE; this allows the nuclear Ca2+ to be regulated autonomously. On the other hand, cytosolic Ca2+ transients can propagate within the nucleus via the nuclear pore complex. The variations in nuclear Ca2+ concentration are important for controlling gene transcription and progression in the cell cycle. Recent data suggest that invaginations of the NE modify the morphology of the nucleus and may affect Ca2+ dynamics in the nucleus and regulate transcriptional activity. © 2012 Soçiété Francaise des Microscopies and Société de Biologie Cellulaire de France.

Receveur-Brechot V.,French National Center for Scientific Research | Durand D.,University Paris - Sud
Current Protein and Peptide Science | Year: 2012

While the crucial role of intrinsically disordered proteins (IDPs) in the cell cycle is now recognized, deciphering their molecular mode of action at the structural level still remains highly challenging and requires a combination of many biophysical approaches. Among them, small angle X-ray scattering (SAXS) has been extremely successful in the last decade and has become an indispensable technique for addressing many of the fundamental questions regarding the activities of IDPs. After introducing some experimental issues specific to IDPs and in relation to the latest technical developments, this article presents the interest of the theory of polymer physics to evaluate the flexibility of fully disordered proteins. The different strategies to obtain 3-dimensional models of IDPs, free in solution and associated in a complex, are then reviewed. Indeed, recent computational advances have made it possible to readily extract maximum information from the scattering curve with a special emphasis on highly flexible systems, such as multidomain proteins and IDPs. Furthermore, integrated computational approaches now enable the generation of ensembles of conformers to translate the unique flexible characteristics of IDPs by taking into consideration the constraints of more and more various complementary experiment. In particular, a combination of SAXS with high-resolution techniques, such as x-ray crystallography and NMR, allows us to provide reliable models and to gain unique structural insights about the protein over multiple structural scales. The latest neutron scattering experiments also promise new advances in the study of the conformational changes of macromolecules involving more complex systems. © 2012 Bentham Science Publishers.

Vincent F.B.,Monash University | Morand E.F.,Monash University | Murphy K.,Monash University | Mackay F.,Monash University | And 2 more authors.
Annals of the Rheumatic Diseases | Year: 2013

The introduction of biologics, especially tumour necrosis factor (TNF) inhibitors, has revolutionized the management of chronic inflammatory diseases. However, at least one third of patients with these diseases, receiving TNF inhibitors either do not respond to treatment, or lose initial responsiveness. For a significant proportion, improvement of clinical response is achieved after switching to another anti-TNF drug, suggesting a basis for failure unrelated to the therapeutic target itself. A likely explanation for this is immunogenicity, as all biologics are potentially immunogenic, and the resulting anti-drug antibodies (ADAb) can theoretically decrease the efficacy of biologics and/or induce adverse events. Indeed, in these chronic inflammatory diseases, many studies have now established correlations between ADAb formation, low serum drug levels, and the failure or loss of response to anti-TNF antibodies. This article will review key findings related to ADAb, and propose a model wherein monitoring of drug levels and ADAb may be a predictive tool leading to a better choice of biologics. Such an approach could improve chronic inflammatory disease management toward a personalized and more cost-effective approach.

Lansberg J.P.,University Paris - Sud | Lansberg J.P.,Ecole Polytechnique - Palaiseau
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2011

We update the study of the polarisation of J/ψ produced in proton-proton collisions at RHIC at s=200 GeV using the QCD-based Colour-Singlet Model (CSM), including next-to-leading order partonic matrix elements from gluon and light quark fusion and leading-order contributions from charm-quark initiated processes. To do so, we also evaluate the corresponding cross section differential in PT which agrees qualitatively with the measurements of PHENIX in the central and forward regions at low PT - for instance below 2 GeV, while emphasising the need for Initial State Radiation (ISR) resummation. At mid PT, we also compare the measurements from PHENIX and STAR with the same evaluation complemented with the dominant αS5 contributions (NNLO*). We find a reasonable agreement with the data. Regarding the polarisation, as shown for previous studies at larger s and PT, the polarisation pattern from gluon and light quark fusion in the helicity frame is drastically modified at NLO and is shown to be increasingly longitudinal. The yield from charm-gluon fusion is found to be slightly transversally polarised. Combining both these contributions with a data-driven range for the polarisation of J/ψ from Χc, we eventually provide an evaluation of the polarisation of the prompt J/Χ yield which is in a good agreement with the experimental data from PHENIX both in the central and forward regions. © 2010 Elsevier B.V.

Millevoi S.,University Paul Sabatier | Moine H.,University of Strasbourg | Vagner S.,French Institute of Health and Medical Research | Vagner S.,University Paris - Sud
Wiley Interdisciplinary Reviews: RNA | Year: 2012

G-quadruplexes are noncanonical structures formed by G-rich DNA and RNA sequences that fold into a four-stranded conformation. Experimental studies and computational predictions show that RNA G-quadruplexes are present in transcripts associated with telomeres, in noncoding sequences of primary transcripts and within mature transcripts. RNA G-quadruplexes at these specific locations play important roles in key cellular functions, including telomere homeostasis and gene expression. Indeed, RNA G-quadruplexes appear as important regulators of pre-mRNA processing (splicing and polyadenylation), RNA turnover, mRNA targeting and translation. The regulatory mechanisms controlled by RNA G-quadruplexes involve the binding of protein factors that modulate G-quadruplex conformation and/or serve as a bridge to recruit additional protein regulators. In this review, we summarize the current knowledge on the role of G-quadruplexes in RNA biology with particular emphasis on the molecular mechanisms underlying their specific function in RNA metabolism occurring in physiological or pathological conditions. © 2012 John Wiley & Sons, Ltd.

Shen H.-M.,National University of Singapore | Codogno P.,University Paris - Sud
Experimental Cell Research | Year: 2012

Macroautophagy or autophagy is a self-digesting mechanism that the cellular contents are engulfed by autophagosomes and delivered to lysosomes for degradation. Although it has been well established that autophagy is an important protective mechanism for cells under stress such as starvation via provision of nutrients and removal of protein aggregates and damaged mitochondria, there is a very complex relation between autophagy and cell death. At present, the molecular cross-talk between autophagy and apoptosis has been well discussed, while the relationship between autophagy and programmed necrotic cell death is less understood. In this review we focus on the role of autophagy in necrotic cell death by detailed discussion on two important forms of necrotic cell death: (i) necroptosis and (ii) poly-(ADP-ribose) polymerase (PARP)-mediated cell death. It is believed that one important aspect of the pro-survival function of autophagy is achieved via its ability to block various forms of necrotic cell death. © 2012 Elsevier Inc.

Battista F.,Lund University | Moskalets M.,Kharkiv Polytechnic Institute | Albert M.,University Paris - Sud | Samuelsson P.,Lund University
Physical Review Letters | Year: 2013

Optimal single electron sources emit regular streams of particles, displaying no low-frequency charge current noise. Because of the wave packet nature of the emitted particles, the energy is, however, fluctuating, giving rise to heat current noise. We investigate theoretically this quantum source of heat noise for an emitter coupled to an electronic probe in the hot-electron regime. The distribution of temperature and potential fluctuations induced in the probe is shown to provide direct information on the single-particle wave function properties and display strong nonclassical features. © 2013 American Physical Society.

Napolitani P.,University Paris - Sud | Colonna M.,National Institute of Nuclear Physics, Italy
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2013

We investigate the occurrence of bifurcations in the dynamical trajectories depicting central nuclear collisions at Fermi energies. The quantitative description of the reaction dynamics is obtained within a new transport model, based on the solution of the Boltzmann-Langevin equation in three dimensions, with a broad applicability for dissipative fermionic dynamics.Dilute systems formed in central collisions are shown to fluctuate between two energetically favourable mechanisms: reverting to a compact shape or rather disintegrating into several fragments. The latter result can be connected to the recent observation of bimodal distributions for quantities characterising fragmentation processes and may suggest new investigations. © 2013 Elsevier B.V.

Dehaene-Lambertz G.,University Paris - Sud | Spelke E.S.,Harvard University
Neuron | Year: 2015

The human infant brain is the only known machine able to master a natural language and develop explicit, symbolic, and communicable systems of knowledge that deliver rich representations of the external world. With the emergence of noninvasive brain imaging, we now have access to the unique neural machinery underlying these early accomplishments. After describing early cognitive capacities in the domains of language and number, we review recent findings that underline the strong continuity between human infants' and adults' neural architecture, with notably early hemispheric asymmetries and involvement of frontal areas. Studies of the strengths and limitations of early learning, and of brain dynamics in relation to regional maturational stages, promise to yield a better understanding of the sources of human cognitive achievements. © 2015 Elsevier Inc.

Deves M.,University Paris - Sud | Deves M.,Institute Of Neurobiologie A Fessard | Bourrat F.,French Institute of Health and Medical Research
Seminars in Cell and Developmental Biology | Year: 2012

Metazoans begin their life as a single cell. Then, this cell enters a more or less protracted period of active cell proliferation, which can be considered as the default cellular state. A crucial event, the developmental cell cycle exit, occurs thereafter. This phenomenon allows for differentiation to happen and regulates the final size of organs and organisms. Its control is still poorly understood. Herein, we review some transcriptional mechanisms of cell cycle exit in animals, and propose to use cellular conveyor belts as model systems for its study. We finally point to evidence that suggests that the mechanisms of developmental cell cycle arrest may have to be maintained in adult tissues. © 2012 Elsevier Ltd.

Durand-Zaleski I.,University Paris - Sud
Hormone Research in Paediatrics | Year: 2011

In the context of health-care costs, containment and economic downturn, there is a question as to whether the high cost of growth hormone (GH) therapy for patients with idiopathic short stature (ISS) is worth the health benefit provided. The economic evaluations of GH for the treatment of patients with ISS have considered gain in height as the major clinical endpoint. The incremental cost of each centimetre of adult height gained due to GH treatment has been estimated to be between £13,500 and £27,200 (€16,400 to €33,100), but could range from £4,300 to £272,000 (€5,200 to €330,900) depending on height gain, GH dose and unit cost, as well as discount rate chosen. Evidence regarding a potential benefit on health-related quality of life is lacking. Copyright © 2011 S. Karger AG, Basel.

Galluzzi L.,University of Paris Descartes | Galluzzi L.,Institute Gustave Roussy | Kepp O.,Institute Gustave Roussy | Kepp O.,French Institute of Health and Medical Research | And 4 more authors.
Nature Reviews Molecular Cell Biology | Year: 2012

Throughout more than 1.5 billion years of obligate endosymbiotic co-evolution, mitochondria have developed not only the capacity to control distinct molecular cascades leading to cell death but also the ability to sense (and react to) multiple situations of cellular stress, including viral infection. In addition, mitochondria can emit danger signals that alert the cell or the whole organism of perturbations in homeostasis, hence promoting the induction of cell-intrinsic or systemic adaptive responses, respectively. As such, mitochondria can be considered as master regulators of danger signalling. © 2012 Macmillan Publishers Limited. All rights reserved.

Graille M.,University Paris - Sud | Graille M.,Ecole Polytechnique - Palaiseau | Seraphin B.,Institute Of Genetique Et Of Biologie Moleculaire Et Cellulaire Igbmc | Seraphin B.,French National Center for Scientific Research | And 2 more authors.
Nature Reviews Molecular Cell Biology | Year: 2012

Living cells require the continuous production of proteins by the ribosomes. Any problem enforcing these protein factories to stall during mRNA translation may then have deleterious cellular effects. To minimize these defects, eukaryotic cells have evolved dedicated surveillance pathways: non-stop decay (NSD), no-go decay (NGD) and non-functional 18S-rRNA decay (18S-NRD). Recent studies support a general molecular framework for these surveillance pathways, the mechanisms of which are intimately related to translation termination. © 2012 Macmillan Publishers Limited. All rights reserved.

Sakai S.,University of Tokyo | Sakai S.,RIKEN | Civelli M.,University Paris - Sud | Imada M.,University of Tokyo
Physical Review Letters | Year: 2016

The dynamics of a microscopic cuprate model, namely, the two-dimensional Hubbard model, is studied with a cluster extension of the dynamical mean-field theory. We find a nontrivial structure of the frequency-dependent self-energies, which describes an unprecedented interplay between the pseudogap and superconductivity. We show that these properties are well described by quasiparticles hybridizing with (hidden) fermionic excitations, emergent from the strong electronic correlations. The hidden fermion enhances superconductivity via a mechanism distinct from a conventional boson-mediated pairing, and originates the normal-state pseudogap. Though the hidden fermion is elusive in experiments, it can solve many experimental puzzles. © 2016 American Physical Society.

Young J.,University Paris - Sud | Young J.,Hopitaux universitaires Paris Sud | Young J.,Institute National Of La Sante
Journal of Clinical Endocrinology and Metabolism | Year: 2012

The term "congenital hypogonadotropic hypogonadism" (CHH) refers to a group of disorders featuring complete or partial pubertal failure due to insufficient secretion of the pituitary gonadotropins LH and FSH. Many boys (or their parents) will seek medical consultation because of partial or absent virilization after 14 yr of age. Small testes are very frequent, but height is generally normal. Laboratory diagnosis of hypogonadotropic hypogonadismis relatively simple, with very low circulating total testosterone and low to low-normal gonadotropin and inhibin B levels. This hormone profile rules out a primary testicular disorder. Before diagnosing CHH, however, it is necessary to rule out a pituitary tumor or pituitary infiltration by imaging studies, juvenile hemochromatosis, and a systemic disorder that, by undermining nutritional status, could affect gonadotropin secretion and pubertal development. Anterior pituitary function must be thoroughly investigated to rule out a more complex endocrine disorder with multiple hormone deficiencies and thus to conclude that the hypogonadotropic hypogonadism is isolated. The most likely differential diagnosis before age 18 yr is constitutional delay of puberty. A part from non-Kallmann syndromic forms, which are often diagnosed during childhood, the two main forms of CHH seen by endocrinologists are Kallmann syndrome, in which CHH is associated with impaired sense of smell, and isolated CHH with normal olfaction. Anosmia can be easily diagnosed by questioning the patient, whereas olfactometry is necessary to determine reliably whether olfaction is normal or partially defective. This step is important be fore embarking on a search for genetic mutations, which will also be useful for genetic counseling. The choice of a particular hormone replacement therapy protocolaimed at virilizing the patient will depend on age at diagnosis and local practices. Copyright © 2012 by The Endocrine Society.

Moussallam B.,University Paris - Sud
European Physical Journal C | Year: 2013

Previous representations of pion-pair production amplitudes by two real photons at low energy, which combine dispersion theoretical constraints with elastic unitarity, chiral symmetry and soft-photon constraints are generalised to the case where one photon is virtual. The constructed amplitudes display explicitly the dependence on the ππ phase-shifts, on pion form factors and on pion polarisabilities. They apply both for space-like and time-like virtualities despite the apparent overlap of the left- and right-hand cuts, by implementing a definition of resonance exchange amplitudes complying with analyticity and consistent limiting prescriptions for the energy variables. Applications are made to the pion generalised polarisabilies, to vector-meson radiative decays, and to the σγ electromagnetic form factor. Finally, an evaluation of the contribution of γππ states in the hadronic vacuum polarisation to the muon g-2 is given, which should be less model dependent than previous estimates. © 2013 Springer-Verlag Berlin Heidelberg and Società Italiana di Fisica.

Gerard C.,University Paris - Sud | Wrochna M.,Joseph Fourier University
Communications in Mathematical Physics | Year: 2015

We construct Hadamard states for the Yang–Mills equation linearized around a smooth, space-compact background solution. We assume the spacetime is globally hyperbolic and its Cauchy surface is compact or equal (Formula presented.). We first consider the case when the spacetime is ultra-static, but the background solution depends on time. By methods of pseudodifferential calculus we construct a parametrix for the associated vectorial Klein–Gordon equation. We then obtain Hadamard two-point functions in the gauge theory, acting on Cauchy data. A key role is played by classes of pseudodifferential operators that contain microlocal or spectral type low-energy cutoffs. The general problem is reduced to the ultra-static spacetime case using an extension of the deformation argument of Fulling, Narcowich and Wald. As an aside, we derive a correspondence between Hadamard states and parametrices for the Cauchy problem in ordinary quantum field theory. © 2015, Springer-Verlag Berlin Heidelberg.

Lena C.,University Paris - Sud
Journal of Mathematical Physics | Year: 2015

We study how the eigenvalues of a magnetic Schrödinger operator of Aharonov-Bohm type depend on the singularities of its magnetic potential. We consider a magnetic potential defined everywhere in R2 except at a finite number of singularities, so that the associated magnetic field is zero. On a fixed planar domain, we define the corresponding magnetic Hamiltonian with Dirichlet boundary conditions and study its eigenvalues as functions of the singularities. We prove that these functions are continuous, and in some cases even analytic. We sketch the connection of this eigenvalue problem to the problem of finding spectral minimal partitions of the domain. © 2015 AIP Publishing LLC.

Lambert S.,Institute Curie | Lambert S.,University Paris - Sud | Carr A.M.,University of Sussex
Chromosoma | Year: 2013

Maintaining genome stability is essential for the accurate transmission of genetic material. Genetic instability is associated with human genome disorders and is a near-universal hallmark of cancer cells. Genetic variation is also the driving force of evolution, and a genome must therefore display adequate plasticity to evolve while remaining sufficiently stable to prevent mutations and chromosome rearrangements leading to a fitness disadvantage. A primary source of genome instability are errors that occur during chromosome replication. More specifically, obstacles to the movement of replication forks are known to underlie many of the gross chromosomal rearrangements seen both in human cells and in model organisms. Obstacles to replication fork progression destabilize the replisome (replication protein complex) and impact on the integrity of forked DNA structures. Therefore, to ensure the successful progression of a replication fork along with its associated replisome, several distinct strategies have evolved. First, there are well-orchestrated mechanisms that promote continued movement of forks through potential obstacles. Second, dedicated replisome and fork DNA stabilization pathways prevent the dysfunction of the replisome if its progress is halted. Third, should stabilisation fail, there are mechanisms to ensure damaged forks are accurately fused with a converging fork or, when necessary, re-associated with the replication proteins to continue replication. Here, we review what is known about potential barriers to replication fork progression, how these are tolerated and their impact on genome instability. © 2013 Springer-Verlag Berlin Heidelberg.

Mura S.,University Paris - Sud
International journal of nanomedicine | Year: 2011

Because of the described hazards related to inhalation of manufactured nanoparticles, we investigated the lung toxicity of biodegradable poly (lactide-co-glycolide) (PLGA) nanoparticles displaying various surface properties on human bronchial Calu-3 cells. Positively and negatively charged as well as neutral nanoparticles were tailored by coating their surface with chitosan, Poloxamer, or poly (vinyl alcohol), respectively. Nanoparticles were characterized in terms of size, zeta potential, and surface chemical composition, confirming modifications provided by hydrophilic polymers. Although nanoparticle internalization by lung cells was clearly demonstrated, the cytotoxicity of the nanoparticles was very limited, with an absence of inflammatory response, regardless of the surface properties of the PLGA nanoparticles. These in vitro results highlight the safety of biodegradable PLGA nanoparticles in the bronchial epithelium and provide initial data on their potential effects and the risks associated with their use as nanomedicines.

Houee-Levin C.,University Paris - Sud | Bobrowski K.,Institute of Nuclear Chemistry and Technology of Poland
Journal of Proteomics | Year: 2013

The method of radiolysis is based upon the interaction of ionising radiation with the solvent (water). One can form the same free radicals as in conditions of oxidative stress (•OH, O2 •-, NO2 •...). Moreover, the quantity of reactive oxygen (ROS) or nitrogen (RNS) species formed in the irradiated medium can be calculated knowing the dose and the radiation chemical yield, G, thus this method is quantitative. The use of the method of radiolysis has provided a wealth of data, especially about the kinetics of the oxidation by various free radicals and their mechanisms, the identification of transients formed, their lifetimes and the possibility to repair them by the so-called antioxidants. In this review we have collected the most recent data about protein oxidation that might be useful to a proteomic approach. This article is part of a Special Issue entitled: Posttranslational Protein modifications in biology and Medicine. © 2013 Elsevier B.V.

Mariette X.,University Paris - Sud
Arthritis Research and Therapy | Year: 2012

In a study in a recent issue of Arthritis Research & Therapy, Yoshimoto and colleagues demonstrate that peripheral monocytes from patients with Sjögren's syndrome (SS) produce significantly higher amounts of B cell-activating factor (BAFF) and interleukin-6 (IL-6) in comparison with normal monocytes. This difference exists at baseline and is amplified after stimulation with interferon-gamma. Increased IL-6 secretion is partially suppressed by an anti-BAFF antibody, suggesting that signal transduction pathways mediated by BAFF are implicated in the regulation of IL-6 production by monocytes. The origin and pathways involved in this higher susceptibility to BAFF-driven IL-6 induction by monocytes of patients with SS are still unknown. © 2012 BioMed Central Ltd.

Foyer C.H.,University of Leeds | Noctor G.,University Paris - Sud
Antioxidants and Redox Signaling | Year: 2013

Our aim is to deliver an authoritative and challenging perspective of current concepts in plant redox signaling, focusing particularly on the complex interface between the redox and hormone-signaling pathways that allow precise control of plant growth and defense in response to metabolic triggers and environmental constraints and cues. Plants produce significant amounts of singlet oxygen and other reactive oxygen species (ROS) as a result of photosynthetic electron transport and metabolism. Such pathways contribute to the compartment-specific redox-regulated signaling systems in plant cells that convey information to the nucleus to regulate gene expression. Like the chloroplasts and mitochondria, the apoplast-cell wall compartment makes a significant contribution to the redox signaling network, but unlike these organelles, the apoplast has a low antioxidant-buffering capacity. The respective roles of ROS, low-molecular antioxidants, redox-active proteins, and antioxidant enzymes are considered in relation to the functions of plant hormones such as salicylic acid, jasmonic acid, and auxin, in the composite control of plant growth and defense. Regulation of redox gradients between key compartments in plant cells such as those across the plasma membrane facilitates flexible and multiple faceted opportunities for redox signaling that spans the intracellular and extracellular environments. In conclusion, plants are recognized as masters of the art of redox regulation that use oxidants and antioxidants as flexible integrators of signals from metabolism and the environment. © Copyright 2013, Mary Ann Liebert, Inc.

Lambert S.,Institute Curie | Lambert S.,University Paris - Sud | Carr A.M.,University of Sussex
Current Opinion in Genetics and Development | Year: 2013

Replication failures induced by replication fork barriers (RFBs) or global replication stress generate many of the chromosome rearrangement (CR) observed in human genomic disorders and cancer. RFBs have multiple causes and cells protect themselves from the consequences of RFBs using three general strategies: preventing expression of RFB activity, stabilising the arrested replisome and, in the case of replisome failure, shielding the fork DNA to allow rebuilding of the replisome. Yeast models provide powerful tools to understand the cellular response to RFBs, delineate pathways that suppress genome instability and define mechanisms by which CRs occur when these fail. Recent progress has identified key features underlying RFBs activity and is beginning to uncover the DNA dynamics that bring about genome instability. © 2012 .

Gaugue I.,University of Paris Pantheon Sorbonne | Gaugue I.,French Institute of Health and Medical Research | Oberto J.,University Paris - Sud | Plumbridge J.,University of Paris Pantheon Sorbonne
Molecular Microbiology | Year: 2014

In Bacillus subtilis separate sets of genes are implicated in the transport and metabolism of the amino sugars, glucosamine and N-acetylglucosamine. The genes for use of N-acetylglucosamine (nagAB and nagP) are found in most firmicutes and are controlled by a GntR family repressor NagR (YvoA). The genes for use of glucosamine (gamAP) are repressed by another GntR family repressor GamR (YbgA). The gamR-gamAP synton is only found in B.subtilis and a few very close relatives. Although NagR and GamR are close phylogenetically, there is no cross regulation between their operons. GlcN6P prevents all binding of GamR to its targets. NagR binds specifically to targets containing the previously identified dre palindrome but its binding is not inhibited by GlcN6P or GlcNAc6P. GamR-like binding sites were also found in some other Bacilli associated with genes for use of chitin, the polymer of N-acetylglucosamine, and with a gene for another GamR homologue (yurK). We show that GamR can bind to two regions in the chi operon of B.licheniformis and that GamR and YurK are capable of heterologous regulation. GamR can repress the B.licheniformislicH-yurK genes and YurK can repress B.subtilisgamA. © 2014 John Wiley & Sons Ltd.

The telluric planets and the asteroid belt display the same internal structure with a metallic inner core and a silicate outer shell. Experimental data and petrological evidence in silicate systems show that granite can be produced by extreme igneous differentiation through various types of igneous processes.On Moon, 4.4-3.9. Ga granite clasts display dry mineral assemblages. They correspond to at least 8 discrete intrusive events. Large K/Ca enrichment and low REE abundances in granite relative to KREEP are consistent with silicate liquid immiscibility, a process observed in melt inclusions within olivine of lunar basalts and in lunar meteorites. Steep-sided domes identified by remote sensing can represent intrusive or extrusive felsic formations.On Mars, black-and-white rhythmic layers observed on the Tharsis rise along the flanks of the peripheral scarps of the Tharsis Montes giant volcanoes suggest the possible eruption of felsic pyroclastites. Though no true granites were found so far in the Martian SNC meteorites, felsic glasses and mesostases were identified and a component close to terrestrial continental (granitic) crust is inferred from trace element and isotope systematics.Venus has suffered extensive volcanic resurfacing, whereas folded and faulted areas resemble terrestrial continents. Near large shield volcanoes, with dominant basaltic compositions, steep-sided domes have been interpreted as non-degassed silicic extrusions. The hypothesis of a granitic component is "tantalising".Extra-terrestrial granite is frequently found as clasts and mesostases in asteroidal meteorites. Porphyritic textures, with alkali feldspar crystals up to several centimetres in size, were observed in silicate enclaves within iron meteorites. In the chondrite clan, polymict breccias can contain granitic clasts, whose provenance is debated. One clast from the Adzhi-Bogdo meteorite yields a 4.53. ±. 0.03. Ga Pb-Pb age, making it the oldest known granite in the solar system.The vast majority of granitic materials recognised so far in the extra-terrestrial record are characterised by ferroan A-type compositions, characterised by high to very high K 2O and medium CaO contents, sodic varieties being exceedingly rare. Textural evidence of graphic quartz-alkali feldspar intergrowths within crystallised products suggests that they are igneous in origin and crystallised quickly from a liquid. In water-depleted to water-free environments, fluorine and chlorine can play significant roles, as their effects on liquidus temperatures and crystallising assemblages are nearly identical to those of water. The distribution of alkalis and alkaline earths cannot be related only to extensive crystal fractionation, but is likely induced by supplementary silicate liquid immiscibility. Medium-temperature silicate liquid immiscibility is well known as a mode of differentiation in experimental petrology studies at very low pressures on systems dominated by Fe, Ti, K, and P as major elements.The ultimate question is, therefore, not whether granite (s.l.) occurs in any given planetary body, but if sufficient volumes of granitic materials could have been produced to constitute stable continental nuclei. © 2012 Elsevier B.V.

Mezard M.,University Paris - Sud | Toninelli C.,French National Center for Scientific Research
IEEE Transactions on Information Theory | Year: 2011

We study the group testing of a set of N items each of which is defective with probability p. We focus on the double limit of small defect probability, p ≪ 1, and large number of variables, N ≫ 1, taking either p → 0 after N → ∞ or p=1/Nβ with β ∈ (0,1/2). In both settings the optimal number of tests which are required to identify with certainty the defectives via a two-stage procedure, T̄(N,p), is known to scale as Np|log p|. Here we determine the sharp asymptotic value of T̄(N,p)/(Np|log p|) and construct a class of two-stage algorithms over which this optimal value is attained. This is done by choosing a proper bipartite regular graph (of tests and variable nodes) for the first stage of the detection. Furthermore we prove that this optimalvalue is also attained on average over a random bipartite graph where all variables have the same degree and the tests connected to a given variable are randomly chosen with uniform distribution among all tests. Finally, we improve the existing upper and lower bounds for the optimal number of tests in the case p=1/Nβ with β ∈[1/2,1). © 2011 IEEE.

Lansberg J.P.,University Paris - Sud
Journal of Physics G: Nuclear and Particle Physics | Year: 2011

We study J/ψ production in pp collisions at √s=1.96 and 7 TeV using the colour-singlet model (CSM), including next-to-leading order (NLO) corrections and dominant α5S contributions (NNLO*). We find that the CSM reproduces the existing data if the upper range of the NNLO* is near the actual - but presently unknown - NNLO. The direct yield polarization for the NLO and NNLO * is increasingly longitudinal in the helicity frame when PT gets larger. When one combines the direct yield with a data-driven range for the polarization of J/ψ from χc, the prompt J/ψ polarization yield polarization in the CSM gets significantly closer to the experimental data from the CDF collaboration. © 2011 IOP Publishing Ltd.

Ciuchini M.,Third University of Rome | Stocchi A.,University Paris - Sud
Annual Review of Nuclear and Particle Science | Year: 2011

With the next-generation experiments, flavor physics is fully entering the era of precision measurements. Its focus is shifting from testing the Standard Model to finding and characterizing New Physics contributions. We review the opportunities offered by future flavor experiments and discuss the expected sensitivities of the most important measurements. We also present some examples of measurable deviations from the Standard Model in the flavor sector generated in a selection of New Physics models, which demonstrate the potentially major contribution of precision flavor physics to the effort of going beyond the Standard Model. © 2011 by Annual Reviews. All rights reserved.

Mambrini Y.,University Paris - Sud | Zaldivar B.,Institute Fisica Teorica
Journal of Cosmology and Astroparticle Physics | Year: 2011

Recently, several astrophysical data or would-be signals has been observed in different dark-matter oriented experiments. In each case, one could fit the data at the price of specific nature of the coupling between the Standard Model (SM) particles and a light Dark Matter candidate: hadrophobic (INTEGRAL, PAMELA) or leptophobic (WMAP Haze, dijet anomalies of CDF, FERMI Galactic Center observation). In this work, we show that when one takes into account the more recent LEP and Tevatron analysis, a light thermal fermionic Dark Matter (10 GeV) that couples to electrons is mainly ruled out if one combines the analysis with WMAP constraints. We also study the special case of scalar dark matter, using a single-photon events simulation to constrain the coupling of dark matter to electron. © 2011 IOP Publishing Ltd and SISSA.

D'Espagnat B.,University Paris - Sud
Foundations of Physics | Year: 2011

Contrary to classical physics, which was strongly objective i. e. could be interpreted as a description of mind-independent reality, standard quantum mechanics (SQM) is only weakly objective, that is to say, its statements, though intersubjectively valid, still merely refer to operations of the mind. Essentially, in fact, they are predictive of observations. On the view that SQM is universal conventional realism is thereby refuted. It is shown however that this does not rule out a broader form of realism, called here 'open realism', restoring the notion of mind-independent reality. © 2011 Springer Science+Business Media, LLC.

Omnes R.,University Paris - Sud
Foundations of Physics | Year: 2011

A famous essay by Wigner is reexamined in view of more recent developments around its topic, together with some remarks on the metaphysical character of its main question about mathematics and natural sciences. © 2011 Springer Science+Business Media, LLC.

Desesquelles P.,University Paris - Sud
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2011

A new method is proposed which allows the building of a signal basis, i.e. a matrix of traces corresponding to identified locations of gamma interactions with the crystal, directly from a set of signals delivered by the detector. The usual on-line algorithms dedicated to the location of the hits can apply this basis to perform signal decomposition. The method also provides Jacobian transforms that can be used to compute very quickly the hit locations in situations when signals are not overlapping. © 2011 Elsevier B.V. All right reserved.

Langlois D.,University Paris Diderot | Van Tent B.,University Paris - Sud
Classical and Quantum Gravity | Year: 2011

We investigate new shapes (in multipole space) of local primordial non-Gaussianities in the cosmic microwave background. Allowing for a primordial isocurvature mode along with the main adiabatic one, the angular bispectrum is in general a superposition of six distinct shapes: the usual adiabatic term, a purely isocurvature component and four additional components that arise from correlations between the adiabatic and the isocurvature modes. We present a class of early Universe models in which various hierarchies between these six components can be obtained, while satisfying the present upper bound on the isocurvature fraction in the power spectrum. Remarkably, even with this constraint, detectable non-Gaussianity could be produced by isocurvature modes. We finally discuss the prospects of detecting these new shapes with the Planck data, including polarization. © 2011 IOP Publishing Ltd.

Chassefiere E.,University Paris - Sud | Chassefiere E.,French National Center for Scientific Research | Leblanc F.,University Pierre and Marie Curie
Earth and Planetary Science Letters | Year: 2011

It has been suggested that Mars' atmospheric CH4 could be produced by crustal hydrothermal systems. The two most plausible mechanisms proposed so far, not exclusive from each other, are homogeneous formation by fluid-rock interaction during magmatic events and serpentinization of ultramafic rocks. The first goal of the present paper is to provide an upper limit on the release rate of serpentinization-derived CH4. Due to the release of numerous H2 molecules together with one CH4 molecule, followed by thermal escape of all released H atoms to space and subsequent H isotopic fractionation, even a relatively modest serpentinization-derived CH4 release acting over geological time scales may result in a significant enrichment of D wrt H in Mars' cryo-hydrosphere, including atmosphere, polar caps and subsurface reservoirs. By assuming that the CH4 release rate has been proportional to the volcanic extrusion rate during the last 4billion years, we calculate the present D/H ratio resulting from the crustal oxidation due to serpentinization, including the additional effect of sulfur oxidation. We show that this rate doesn't exceed 20% (within a factor of 2) of the estimated present value of the CH4 release rate. If not, the present D/H ratio on Mars would be larger than observed (~5 SMOW). This result suggests that, either the production of CH4 is sporadic with a present release rate larger than the average rate, or there are other significant sources of CH4 like homogeneous formation from mantle carbon degassing or bacterial activity. Second, assuming further that most of the H isotopic fractionation observed today is due to serpentinization, we show that a ~400m thick global equivalent layer of water may have been stored in serpentine since the late Noachian. This result doesn't depend on the chemical form of the released hydrogen (H2 or CH4). Such a quantity is generally considered as the amount required for explaining the formation of valley networks on Mars. Serpentinization therefore appears as a potentially efficient sink of water on Mars, much more efficient than O escape' for having removed large amounts of water from the hydrosphere. © 2011 Elsevier B.V.

Rousseau D.,University Paris - Sud
IEEE Software | Year: 2012

David Rousseau describes the extensive enormous software development effort associated with the discovery of the Higgs boson as an important component of the Standard Model. The Atlas software has been developed and used by researchers at CERN to help in the discovery of the Higgs boson. Atlas's different processing stages are performed on the Atlas grid sites except for the initial reconstruction stage. Each site offers CPU and disk resources and has the latest Atlas software preinstalled. Copies of the analysis datasets are spread sparsely throughout these centers and physicists submit tasks to the grid by specifying the input dataset to be processed and the exact configuration of the software to be run. The grid system automatically splits the task into separate jobs and sends the job to where the dataset is available. The framework of all the Atlas software follows a whiteboard architecture implemented in C++.

Fu H.S.,Swedish Institute of Space Physics | Fu H.S.,Beihang University | Khotyaintsev Y.V.,Swedish Institute of Space Physics | Vaivads A.,Swedish Institute of Space Physics | And 2 more authors.
Nature Physics | Year: 2013

The mechanism that produces energetic electrons during magnetic reconnection is poorly understood. This is a fundamental process responsible for stellar flares, substorms, and disruptions in fusion experiments. Observations in the solar chromosphere an. The Earth's magnetosphere indicate significant electron acceleration during reconnection, whereas in the solar wind, energetic electrons are absent. Here we show that energetic electron acceleration is caused by unsteady reconnection. I. The Earth's magnetosphere an. The solar chromosphere, reconnection is unsteady, so energetic electrons are produced; in the solar wind, reconnection is steady, so energetic electrons are absent. The acceleration mechanism is quasi-adiabatic: betatron and Fermi acceleration in outflow jets are two processes contributing to electron energization during unsteady reconnection. The localized betatron acceleration in the outflow is responsible for at least half of the energy gain fo. The peak observed fluxes. © 2013 Macmillan Publishers Limited. All rights reserved.

Cozza A.,University Paris - Sud
IEEE Transactions on Antennas and Propagation | Year: 2012

A generalized time-reversal (TR) technique for the generation of coherent wavefronts within complex media is presented in this paper. Although completely general, this method is primarily considered for testing purposes herein, where an equipment under test is submitted to a series of impinging wavefronts with varying features. Electromagnetic compatibility, antenna testing as well as telecommunications facilities where complex-wavefront schemes (e.g., multi-path configurations) are required, could benefit from the proposed approach. The main advantages and limitations of current standard TR approaches are reviewed in this respect, exposing their inadequacy for this particular context. The proposed alternative technique, named time-reversal electromagnetic chamber (TREC) is introduced and studied by means of a formal theoretical analysis, showing how a reverberation chamber (RC) supporting a diffused-field condition can be operated as a generator of deterministic pulsed wavefronts. The TREC is demonstrated to be capable of generating arbitrary wavefronts with a remarkable accuracy, allowing to revisit the RC as a deterministic facility: the main advantages of RCs and anechoic ones are merged, leading to a new facility capable of potentially generating in real-time pulsed wavefronts while using low input energies, without requiring neither mechanical displacements nor any special features of the sources. © 1963-2012 IEEE.

Monsef F.,University Paris - Sud
IEEE Transactions on Electromagnetic Compatibility | Year: 2012

The physical parameter well adapted to assess the degree of overmodedness of a reverberation chamber (RC) is the number MM of modes overlapping in a mode bandwidth. The lowest usable frequency of an RC often corresponds to a low modal overlap of one or two modes. Notwithstanding, in spite of this poor number of modes the RC still works. We show, using Monte Carlo simulation, that the number of modes must, in fact, not be restrained to MM and that the number of modes contributing to the field statistics can be, even at low modal overlap, somewhat larger than expected. © 1964-2012 IEEE.

Di Renzo M.,University Paris - Sud | Haas H.,University of Edinburgh
IEEE Communications Letters | Year: 2010

In this Letter, we show that the performance of Space Shift Keying (SSK) modulation can be improved via opportunistic power allocation methods. For analytical tractability, we focus on a 2 × 1 MultipleInputMultipleOutput (MIMO) system setup over correlated Rayleigh fading channels. A closedform solution of the optimal power allocation problem is derived, and it is shown that the transmitpower of each transmitantenna should be chosen as a function of the power imbalance ratio and correlation coefficient of the transmitreceive wireless links. Numerical results are shown to substantiate the analytical derivation and the claimed performance improvement. © 2010 IEEE.

Marine biogenic carbonates formed by invertebrates (e.g. corals and mollusks) represent complex composites of one or more mineral phases and organic molecules. This complexity ranges from the macroscopic structures observed with the naked eye down to sub micrometric structures only revealed by micro analytical techniques. Understanding to what extent and how organisms can control the formation of these structures requires that the mineral and organic phases can be identified and their spatial distribution related. Here we demonstrate the capability of confocal Raman microscopy applied to cross sections of a shell of Nerita undata to describe the distribution of calcite and aragonite including their crystallographic orientation with high lateral resolution (∼300 nm). Moreover, spatial distribution of functional groups of organic compounds can be simultaneously acquired, allowing to specifically relate them to the observed microstructures. The data presented in this case study highlights the possible new contributions of this method to the description of modalities of Nerita undata shell formation, and what could be expected of its application to other marine biogenic carbonates. Localization of areas of interest would also allow further investigations using more localized methods, such as TEM that would provide complementary information on the relation between organic molecules and crystal lattice. © 2011 Author(s).

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.

Goerbig M.O.,University Paris - Sud
Reviews of Modern Physics | Year: 2011

The basic aspects of electrons in graphene (two-dimensional graphite) exposed to a strong perpendicular magnetic field are reviewed. One of its most salient features is the relativistic quantum Hall effect, the observation of which has been the experimental breakthrough in identifying pseudorelativistic massless charge carriers as the low-energy excitations in graphene. The effect may be understood in terms of Landau quantization for massless Dirac fermions, which is also the theoretical basis for the understanding of more involved phenomena due to electronic interactions. The role of electron-electron interactions both in the weak-coupling limit, where the electron-hole excitations are determined by collective modes, and in the strong-coupling regime of partially filled relativistic Landau levels are presented. In the latter limit, exotic ferromagnetic phases and incompressible quantum liquids are expected to be at the origin of recently observed (fractional) quantum Hall states. Furthermore, the electron-phonon coupling in a strong magnetic field is discussed. Although the present review has a dominant theoretical character, a close connection with available experimental observation is intended. © 2011 American Physical Society.

Machado-Pinilla R.,Yeshiva University | Liger D.,University Paris - Sud | Leulliot N.,University of Paris Descartes | Meier U.T.,Yeshiva University
RNA | Year: 2012

The AAA+ ATPases pontin and reptin function in a staggering array of cellular processes including chromatin remodeling, transcriptional regulation, DNA damage repair, and assembly of macromolecular complexes, such as RNA polymerase II and small nucleolar (sno) RNPs. However, the molecular mechanism for all of these AAA+ ATPase associated activities is unknown. Here we document that, during the biogenesis of H/ACA RNPs (including telomerase), the assembly factor SHQ1 holds the pseudouridine synthase NAP57/dyskerin in a viselike grip, and that pontin and reptin (as components of the R2TP complex) are required to pry NAP57 from SHQ1. Significantly, the NAP57 domain captured by SHQ1 harbors most mutations underlying X-linked dyskeratosis congenita (X-DC) implicating the interface between the two proteins as a target of this bone marrow failure syndrome. Homing in on the essential first steps of H/ACA RNP biogenesis, our findings provide the first insight into the mechanism of action of pontin and reptin in the assembly of macromolecular complexes. Copyright © 2012 RNA Society.

Moller A.P.,University Paris - Sud | Garamszegi L.Z.,CSIC - Donana Biological Station
Behavioral Ecology | Year: 2012

Flight initiation distances (FIDs) of animals approached by a potential predator provide information about the risk that individuals are willing to take given their state and the environment. Species differ in mean and variance in FID, suggesting that species with a large variance in FID have individuals that take either small or great risks, whereas species with a small variance are composed of individuals that are homogeneous in their risk-taking behavior. Here, we investigate the correlations between interspecific variance in risk-taking behavior and habitat selection, breeding range and population size, dispersal, and life history. Greater between individual variation in risk-taking behavior for a given average level of risk taking would imply that more different habitats could be exploited, resulting in larger local and global population sizes and larger ranges. There should be a link between dispersal distances and FID because individuals of risk-averse species should encounter greater difficulties of finding suitable breeding habitats. High local and global population sizes should select for fast life histories with early age at first reproduction, high annual fecundity, low juvenile survival, and fast rates of senescence in species with variable FIDs. Finally, a greater diversity of habitat use should select for a longer reproductive season in species with more variable FIDs. Analyses of FIDs for 133 species of birds revealed results largely consistent with these predictions. Because risk taking correlates with other kinds of behavior that constitute a syndrome behavioral syndromes can play an important role in producing ecological syndromes (i.e., correlations between ecological traits). © 2012 The Author.

Scarabin P.-Y.,University Paris - Sud
Climacteric | Year: 2014

Venous thromboembolism (VTE) is a common and potentially fatal disease in postmenopausal women. VTE has emerged as the most prevalent adverse effect of oral estrogens in 50-60-year-old women. Obesity and VTE history can be easily used to identify women at high risk but genetic screening is not cost-effective. Based on consistent biological and epidemiological findings, transdermal estrogen is the safest option with respect to VTE, especially in women at high risk. There is strong evidence that VTE risk is greater in women using medroxyprogesterone acetate compared with those receiving other progestins. Based on observational data, progesterone appears safe with respect to VTE. More research and action are needed to avert the hepatic first-pass effect of oral estrogens and to increase awareness of hormone-related VTE. Improving individual risk stratification and a personalized approach to hormone therapy are major challenges for future work. © 2014 International Menopause Society.

Sarsa A.,University of Cordoba, Spain | Le Sech C.,University Paris - Sud
Journal of Chemical Theory and Computation | Year: 2011

Variational Monte Carlo method is a powerful tool to determine approximate wave functions of atoms, molecules, and solids up to relatively large systems. In the present work, we extend the variational Monte Carlo approach to study confined systems. Important properties of the atoms, such as the spatial distribution of the electronic charge, the energy levels, or the filling of electronic shells, are modified under confinement. An expression of the energy very similar to the estimator used for free systems is derived. This opens the possibility to study confined systems with little changes in the solution of the corresponding free systems. This is illustrated by the study of helium atom in its ground state 1S and the first 3S excited state confined by spherical, cylindrical, and plane impenetrable surfaces. The average interelectronic distances are also calculated. They decrease in general when the confinement is stronger; however, it is seen that they present a minimum for excited states under confinement by open surfaces (cylindrical, planes) around the radii values corresponding to ionization. The ground 2S and the first 2P and 2D excited states of the lithium atom are calculated under spherical constraints for different confinement radii. A crossing between the 2S and 2P states is observed around rc = 3 atomic units, illustrating the modification of the atomic energy level under confinement. Finally the carbon atom is studied in the spherical symmetry by using both variational and diffusion Monte Carlo methods. It is shown that the hybridized state sp3 becomes lower in energy than the ground state 3P due to a modification and a mixing of the atomic orbitals s, p under strong confinement. This result suggests a model, at least of pedagogical interest, to interpret the basic properties of carbon atom in chemistry. © 2011 American Chemical Society.

Holland I.B.,University Paris - Sud
Essays in biochemistry | Year: 2011

This chapter concentrates mainly on structural and mechanistic aspects of ABC (ATP-binding cassette) transporters and, as an example of the physiological significance of these proteins, on lipid transport, vitally important for human health. The chapter considers those aspects of ABC transporter function that appear reasonably well established, those that remain controversial and what appear to be emerging themes. Although we have seen dramatic progress in ABC protein studies in the last 20 years, we are still far from a detailed molecular understanding of function. Nevertheless two critical steps - capture and release of allocrites (transport substrates) involving a binding cavity in the membrane domain, and hydrolysis of ATP by the NBD (nucleotide-binding domain) dimer - are now described by persuasive and testable models: alternating access, and sequential firing of catalysis sites respectively. However, these need to be tested rigorously by more structural and biochemical studies. Other aspects considered include the level at which ATP binding and dimer activation are controlled, the nature of the power stroke delivering mechanical energy for transport, and some unexpected and intriguing differences between importers and exporters. The chapter also emphasizes that some ABC transporters, although important for elimination of toxic compounds (xenobiotics), are also increasingly seen to play crucial roles in homoeostatic regulation of membrane biogenesis and function through translocation of endogenous allocrites such as cholesterol. Another emerging theme is the identification of accessory domains and partners for ABC proteins, resulting in a corresponding widening of the range of activities. Finally, what are the prospects for translational research and ABC transporters?

Moller A.P.,University Paris - Sud | Ibanez-Alamo J.D.,University of Granada
Animal Behaviour | Year: 2012

Altered predation risk in urban environments may contribute to animals becoming successfully urbanized by individuals from rural habitats. Escape behaviour has evolved to allow an individual to escape once captured by a predator. We tested whether altered predation risk in urban environments is associated with colonization of such habitats by comparing escape behaviour of 1132 individual birds belonging to 15 species from nearby rural and urban populations when captured by a human. Raptors (of which the Eurasian sparrowhawk, Accipiter nisus, was one of the most common species) were more common in rural than in urban habitats, whereas cats, Felis catus, showed the opposite pattern. There were consistent differences in escape behaviour between habitats, showing divergence in behaviour from the ancestral rural state. Urban birds wriggled less, showed higher tonic immobility, more often lost feathers, were less aggressive by biting less often, and emitted fear screams and alarm calls more often than rural birds. Furthermore, differences in escape behaviour between habitats were related to susceptibility to predation by sparrowhawks, as expected if differences in behaviour were due to differences in predation risk. Finally, an analysis of differences in escape behaviour between rural and urban birds revealed a significant relationship with time since urbanization, suggesting that escape behaviour has changed in urban environments over time. These findings suggest that release from predation and change in predator community associated with urbanization has altered the antipredator behaviour of birds colonizing towns and cities. © 2012 The Association for the Study of Animal Behaviour.

Environmental conditions experienced in early life may shape subsequent phenotypic traits including life history. We investigated how predation risk caused by domestic cats (Felis silvestris catus) and local breeding density affected patterns of reproductive and survival senescence in Barn Swallows (Hirundo rustica) breeding semicolonially in Denmark. We recorded the abundance of cats and the number of breeding pairs at 39 breeding sites during 24 years and related these to age-specific survival rate and reproductive senescence to test predictions of the life history theory of senescence. We found evidence for actuarial senescence for the first time in this species. Survival rate increased until reaching a plateau in midlife and then decreased later. We also found that survival rate was higher for males than females. Local breeding density or predation risk did not affect survival as predicted by theory. Barn Swallows with short lives did not invest more in reproduction in early life, inconsistent with expectations for trade-offs between reproduction and survival as theory suggests. However, we found that the rate of reproductive decline during senescence was steeper for individuals exposed to intense competition, and predation pressure accelerated the rate of reproductive senescence, but only in sites with many breeding pairs. These latter results are in accordance with one of the predictions suggested by the life history theory of aging. These results emphasize the importance of considering intraspecific competition and interspecific interactions such as predation when analyzing reproductive and actuarial senescence. ©.

Moller A.P.,University Paris - Sud
Behavioral Ecology | Year: 2012

Large animals have longer flight distances when approached by a potential predator than small animals, and predators therefore have longer flight distances than their prey. The ubiquitous presence of humans in urban areas selects for differential invasion by animals with short flight distances, and adaptation to urban environments results in further reductions in flight distance. Because prey are better able to cope with the proximity of humans than predators due to differences in flight distance, urban areas may act as refuges. Predators on average have a flight distance that is 8 times larger than that of their prey. In urban areas, humans were present within a distance of 54 m (the mean flight distance of raptor species) 16% of the time and 4% of the time within a distance of 7 m (the mean flight distance of prey species). In contrast, humans were present 1.2% of the time within a distance of 54 m but only 0.1% of the time within a distance of 7 m in rural habitats. Therefore, prey gained a 10-fold increase in predator refuge in urban compared with rural habitats. The reduction in flight distance between the ancestral rural and the current urban habitats decreased with the difference in flight distance between raptors and that of prey. The difference in flight distance between predators and that of prey increased with increasing preference of prey by sparrowhawks Accipiter nisus relative to their abundance, providing evidence of a selective advantage for prey. These results suggest that birds that are prey of raptors enjoy a selective advantage from association with humans. © 2012 The Author.

Gabbanini C.,National Research Council Italy | Dulieu O.,University Paris - Sud
Physical Chemistry Chemical Physics | Year: 2011

Ultracold metastable RbCs molecules are observed in a double species magneto-optical trap through photoassociation near the Rb(5S1/2) + Cs(6P3/2) dissociation limit followed by radiative stabilization. The molecules are formed in their lowest triplet electronic state and are detected by resonance enhanced two-photon ionization through the previously unobserved (3)3Π ← a3Σ+ band. The large rotational structure of the observed photoassociation lines is assigned to the lowest vibrational levels of the 0+ or 0- excited states correlated to the Rb(5P1/2) + Cs(6S1/2) dissociation limit. This demonstrates the possibility of inducing direct photoassociation in heteronuclear alkali-metal molecules at a short internuclear distance, as pointed out earlier [J. Deiglmayr et al., Phys. Rev. Lett., 2008, 101, 13304]. © the Owner Societies 2011.

Lansberg J.-P.,University Paris - Sud | Shao H.-S.,Beijing University of Technology | Shao H.-S.,CERN
Physical Review Letters | Year: 2013

We proceed for the first time to the evaluation of the Born cross section for J/ψ+ηc production, namely, via g+g→J/ ψ+ηc+g, and show that it has a harder PT spectrum than the J/ψ-pair yield at the Born level. If one stuck to a comparison at the Born level, one would conclude that J/ψ+ηc production would surpass that of J/ψ+J/ψ at large PT. This is nonetheless not the case since J/ψ-pair production, as for single J/ψ, receives leading-PT contributions at higher orders in αs. We also present the first evaluation of these leading-PT next-to-leading order contributions. These are indeed significant for increasing PT and are of essential relevance for comparison with forthcoming data. We also compute kinematic correlations relevant for double-parton-scattering studies. Finally, we evaluate the polarization of a J/ψ accompanied by either an ηc or a J/ψ and another light parton. These results may be of great help to understand the polarization of quarkonia produced at high energies. © 2013 American Physical Society.

Rault J.,University Paris - Sud
European Physical Journal E | Year: 2012

The thermodynamical and mechanical properties of (fragile and strong) glass are modeled based on a generalised activation energy relationship log τ = ΔGβ/RTn(T′) for the α process of glass-forming liquids. This cooperative process involves 1/n(T′) elementary β motions of activation Gibbs energy ΔGβ dependent on the equivalent temperature T′, the temperature of the liquid in equilibrium having the volume of the glass, function of temperature and aging conditions. From this modified VFT law the relaxation of any properties (V , H, stress, creep) can be calculated and approximated by the Kohlrausch function. This model predicts consistency relationships for: a) the temperature (and aging time) variation of the Kohlrausch exponent; b) the temperature dependence of the stabilisation time domain of strong and fragile glass; c) the linear relation between the activation parameters (E* energy, S* entropy, V* volume) of the α and β transition. The Lawson and Keyes (LK) relations are recalled and it is shown that these relations (somewhat equivalant to the compensation law or Meyer-Neldel rule) are observed generally in glass. Morever the (macroscopic) ratios ΔH/ΔV observed during aging or after a temperature jump and the (microscopic) ratio E*/V* are found equal to κγ (κ compressibily, γ Grüneisen parameter), in agreement with the LK predictions. From various experiments and in agreement with predictions of this model we conclude that the Grüneisen parameter γB (pressure derivative of the bulk modulus) and the Mean Square Displacement (MSD) characterising the anharmonicity of solids (and liquids) are the main parameters which govern the relaxation properties of the glass state. Linear relations between the parameters γB, the fragility m, and the Kohlrausch exponent ng at Tg are explained. These correlations underscore a strong relationship between the fragilty of glass formers and the extent of the anharmonicity in the interatomic interactions. © 2012 EDP Sciences/Società Italiana di Fisica/Springer-Verlag.

Schlumberger M.,University Paris - Sud
Journal of endocrinological investigation | Year: 2012

A small but not irrelevant percentage of differentiated thyroid cancers become refractory to radioiodine treatment either because they lose the ability of taking up iodine over the time or because, despite a persistent uptaking ability, the effect of the radioiodine is lost in terms of tumor burden reduction. These patients receive only few and transient benefits from other conventional therapies and particularly from chemotherapy. In the last decade, several new drugs have been discovered as potentially useful and tested in clinical trials. They are mainly represented by protein kinase inhibitor molecules that should be proposed to advanced and progressive 131I refractory thyroid cancer patients by enrolling them in clinical trials or by the "off label" use of the drug.

Andreeva V.A.,University Paris - Sud | Pokhrel P.,University of Hawaii at Manoa
Psycho-Oncology | Year: 2013

Objective Many countries host growing Eastern European immigrant communities whose breast cancer preventive behaviors are largely unknown. Thus, we aimed to synthesize current evidence regarding secondary prevention via breast cancer screening utilized by that population. Methods All observational, general population studies on breast cancer screening with Eastern European immigrant women and without any country, language, or age restrictions were identified. Screening modalities included breast self-examination, clinical breast examination, and mammography. Results The selected 30 studies were published between 1996 and 2013 and came from Australia, Canada, Denmark, Germany, Israel, the Netherlands, Spain, Switzerland, the UK, and the USA. The reported prevalence of monthly breast self-examination was 0-48%; for yearly clinical breast examination 27-54%; and for biennial mammography 0-71%. The substantial methodologic heterogeneity prevented a meta-analysis. Nonetheless, irrespective of host country, healthcare access, or educational level, the findings consistently indicated that Eastern European immigrant women underutilize breast cancer screening largely because of insufficient knowledge about early detection and an external locus of control regarding decision making in health matters. Conclusions This is a vulnerable population for whom the implementation of culturally tailored breast cancer screening programs is needed. As with other underscreened immigrant/minority groups, Eastern European women's inadequate engagement in prevention is troublesome as it points to susceptibility not only to cancer but also to other serious conditions for which personal action and responsibility are critical. Copyright © 2013 John Wiley & Sons, Ltd.

Dargent-Molina P.,University Paris - Sud
Global health promotion | Year: 2013

This paper reviews the literature that contributed to the design of the 'Ossébo' intervention and describes the study that is underway. Falls and fall-related injuries are a major cause of morbidity and mortality among older people. Extensive research into falls prevention has established physical exercise as an efficient method to reduce falls, but the effect of exercise on serious injuries caused by falls remains unclear. Moreover, populations that would benefit most from these interventions, as well as factors that determine adherence to exercise remain underreported. THE OSSÉBO INTERVENTION: 'Ossébo' is an on-going multicenter randomized controlled trial, aiming to assess the effect of a two-year community-based group physical exercise program on the prevention of falls among women aged 75-85 years old. The primary outcome examined is the rate of falls and injurious falls: secondary outcomes include functional capacities, fear of falling and quality of life. This study will help determine the effectiveness of a large scale falls prevention program and the factors that can potentially assist its success.

Goubet N.,University Pierre and Marie Curie | Richardi J.,University Pierre and Marie Curie | Albouy P.-A.,University Paris - Sud | Pileni M.-P.,University Pierre and Marie Curie
Advanced Functional Materials | Year: 2011

Here, two mechanisms of fcc Au supracrystal (assembly of Au nanocrystals) growth are proposed. The sizes of the Au nanocrystals and the solvent in which they are dispersed are major parameters that determine the final morphology of nanocrystal assemblies; films by layer-by-layer growth (heterogeneous growth), characterized by their plastic deformation, or well-defined shapes grown in solution (homogeneous growth). Experiments supported by simulations demonstrate that supracrystal nucleation is mainly driven by solvent-mediated interactions and not solely by the van der Waals attraction between nanocrystal cores, as widely assumed in the literature. With a low size distribution, gold nanocrystals can crystallize in supracrystals. These mesostructures show different morphologies. Here we show the influence of the nanocrystals size and solvent on the supracrystal nucleation, which controls the supracrystalline shape. Brownian dynamics simulations supported by experiments demonstrate that supracrystal nucleation is mainly driven by solvent-mediated interactions and not solely by the van der Waals attraction between nanocrystal cores, as widely assumed in the literature. The plastic deformation of film made of these supracrystals is also discussed. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chen Z.,University Paris - Sud
Celestial Mechanics and Dynamical Astronomy | Year: 2016

In this paper, the (Formula presented.)-minimization for the translational motion of a spacecraft in the circular restricted three-body problem (CRTBP) is considered. Necessary conditions are derived by using the Pontryagin Maximum Principle (PMP), revealing the existence of bang-bang and singular controls. Singular extremals are analyzed, recalling the existence of the Fuller phenomenon according to the theories developed in (Marchal in J Optim Theory Appl 11(5):441–486, 1973; Zelikin and Borisov in Theory of Chattering Control with Applications to Astronautics, Robotics, Economics, and Engineering. Birkhäuser, Basal 1994; in J Math Sci 114(3):1227–1344, 2003). The sufficient optimality conditions for the (Formula presented.)-minimization problem with fixed endpoints have been developed in (Chen et al. in SIAM J Control Optim 54(3):1245–1265, 2016). In the current paper, we establish second-order conditions for optimal control problems with more general final conditions defined by a smooth submanifold target. In addition, the numerical implementation to check these optimality conditions is given. Finally, approximating the Earth-Moon-Spacecraft system by the CRTBP, an (Formula presented.)-minimization trajectory for the translational motion of a spacecraft is computed by combining a shooting method with a continuation method in (Caillau et al. in Celest Mech Dyn Astron 114:137–150, 2012; Caillau and Daoud in SIAM J Control Optim 50(6):3178–3202, 2012). The local optimality of the computed trajectory is asserted thanks to the second-order optimality conditions developed. © 2016 Springer Science+Business Media Dordrecht

Chargueraud A.,University Paris - Sud
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2013

In spite of the popularity of small-step semantics, big-step semantics remain used by many researchers. However, big-step semantics suffer from a serious duplication problem, which appears as soon as the semantics account for exceptions and/or divergence. In particular, many premises need to be copy-pasted across several evaluation rules. This duplication problem, which is particularly visible when scaling up to full-blown languages, results in formal definitions growing far bigger than necessary. Moreover, it leads to unsatisfactory redundancy in proofs. In this paper, we address the problem by introducing pretty-big-step semantics. Pretty-big-step semantics preserve the spirit of big-step semantics, in the sense that terms are directly related to their results, but they eliminate the duplication associated with big-step semantics. © 2013 Springer-Verlag.

Niccoli G.,CNRS Physics Laboratory | Terras V.,University Paris - Sud
Letters in Mathematical Physics | Year: 2015

Generic inhomogeneous integrable XXZ chains with arbitrary spins are studied by means of the quantum separation of variables (SOV) method. Within this framework, a complete description of the spectrum (eigenvalues and eigenstates) of the antiperiodic transfer matrix is derived in terms of discrete systems of equations involving the inhomogeneity parameters of the model. We show here that one can reformulate this discrete SOV characterization of the spectrum in terms of functional T − Q equations of Baxter’s type, hence proving the completeness of the solutions to the associated systems of Bethe-type equations. More precisely, we consider here two such reformulations. The first one is given in terms of Q-solutions, in the form of trigonometric polynomials of a given degree $${\mathsf{N}_s}$$Ns, of a one-parameter family of T − Q functional equations with an extra inhomogeneous term. The second one is given in terms of Q-solutions, again in the form of trigonometric polynomials of degree $${\mathsf{N}_s}$$Ns but with double period, of Baxter’s usual (i.e., without extra term) T − Q functional equation. In both cases, we prove the precise equivalence of the discrete SOV characterization of the transfer matrix spectrum with the characterization following from the consideration of the particular class of Q-solutions of the functional T − Q equation: to each transfer matrix eigenvalue corresponds exactly one such Q-solution and vice versa, and this Q-solution can be used to construct the corresponding eigenstate. © 2015, Springer Science+Business Media Dordrecht.

Fert A.,Thales Alenia | Fert A.,University Paris - Sud | Levy P.M.,New York University
Physical Review Letters | Year: 2011

The spin Hall effect is a promising way for transforming charge currents into spin currents in spintronic devices. Large values of the spin Hall angle, the characteristic parameter of the yield of this transformation, have been recently found in noble metals doped with nonmagnetic impurities. We show that this can be explained by resonant scattering off impurity states split by the spin-orbit interaction. By using as an example copper doped with 5d impurities we describe the general conditions and provide a guide for experimentalists for obtaining the largest effects. © 2011 American Physical Society.

Mandal T.,Chennai Mathematical Institute | Mitra S.,University Paris - Sud
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

Models with quark and lepton compositeness predict the existence of colored partners of the Standard Model leptons. In this paper we study the LHC phenomenology of a charged colored lepton partner, namely the color octet electron, e8, in an effective theory framework. We explore various mechanisms for resonant production of e8's. With the pair production channel, the 14 TeV LHC can probe e8's with masses up to 2.5 TeV (2.8 TeV) with 100 fb-1 (300 fb-1) of integrated luminosity. A common feature in all the resonant production channels is the presence of two high-pT electrons and at least one high-pT jet in the final state. Using this feature, we implement a search method where the signal is a combination of pair and single production events. This method has potential to increase the LHC's reach significantly. Using the combined signal, we estimate the LHC discovery potential for the e8's. Our analysis shows that the LHC with 14 TeV center-of-mass energy and 100 fb-1 (300 fb-1) of integrated luminosity can probe e8's with masses up to 3.4 TeV (4 TeV) for the compositeness scale of 5 TeV. © 2013 American Physical Society.

Maynar P.,University of Seville | Trizac E.,University Paris - Sud
Physical Review Letters | Year: 2011

In its continuous version, the entropy functional measuring the information content of a given probability density may be plagued by a "measure" problem that results from improper weighting of phase space. This issue is addressed considering a generic collision process whereby a large number of particles or agents randomly and repeatedly interact in pairs, with prescribed conservation law(s). We find a sufficient condition under which the stationary single-particle distribution function maximizes an entropylike functional, that is free of the measure problem. This condition amounts to a factorization property of the Jacobian associated with the binary collision law, from which the proper weighting of phase space directly follows. © 2011 American Physical Society.

Belanger G.,University of Savoy | Dumont B.,CNRS Laboratory of Subatomic Physics & Cosmology | Ellwanger U.,University Paris - Sud | Gunion J.F.,University of California at Davis | Kraml S.,CNRS Laboratory of Subatomic Physics & Cosmology
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

The most recent LHC data have provided a considerable improvement in the precision with which various Higgs production and decay channels have been measured. Using all available public results from ATLAS, CMS and the Tevatron, we derive for each final state the combined confidence level contours for the signal strengths in the (gluon fusion+top-quark pair associated production) versus (vector boson fusion + associated production with vector bosons) space. These "combined signal strength ellipses" can be used in a simple, generic way to constrain a very wide class of new physics models in which the couplings of the Higgs boson deviate from the Standard Model prediction. Here, we use them to constrain the reduced couplings of the Higgs boson to up-quarks, down-quarks/leptons and vector boson pairs. We also consider new physics contributions to the loop-induced gluon-gluon and photon-photon couplings of the Higgs, as well as invisible/unseen decays. Finally, we apply our fits to some simple models with an extended Higgs sector, in particular to two-Higgs-doublet models of Type I and Type II, the inert doublet model, and the Georgi-Machacek triplet Higgs model. © 2013 American Physical Society.

Galtier S.,University Paris - Sud | Galtier S.,Institut Universitaire de France
Astrophysical Journal | Year: 2012

We investigate a class of axisymmetric magnetohydrodynamic turbulence which satisfies the exact relation for third-order Elsässer structure functions. Following the critical balance conjecture, we assume the existence of a power-law relation between correlation length scales along and transverse to the local mean magnetic field direction. The flow direction of the vector third-order moments F ± is then along axisymmetric concave/convex surfaces, the axis of symmetry being given by the mean magnetic field. Under this consideration, the vector F ± satisfies a simple Kolmogorov law which depends on the anisotropic parameter a ±, which measures the concavity of the surfaces. A comparison with recent in situ multispacecraft solar wind observations is made; it is concluded that the underlying turbulence is very likely convex. A discussion is given about the physical meaning of such an anisotropy. © 2012. The American Astronomical Society. All rights reserved.

Kruger M.,Massachusetts Institute of Technology | Emig T.,University Paris - Sud | Kardar M.,Massachusetts Institute of Technology
Physical Review Letters | Year: 2011

The Casimir force between arbitrary objects in equilibrium is related to scattering from individual bodies. We extend this approach to heat transfer and Casimir forces in nonequilibrium cases where each body, and the environment, is at a different temperature. The formalism tracks the radiation from each body and its scatterings by the other objects. We discuss the radiation from a cylinder, emphasizing its polarized nature, and obtain the heat transfer between a sphere and a plate, demonstrating the validity of proximity transfer approximation at close separations and arbitrary temperatures. © 2011 American Physical Society.

Sazdjian H.,University Paris - Sud
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

Using gauge invariant quark Green's functions, defined with path-ordered gluon field phase factors along polygonal lines, and functional relations among them, two compatible bound state equations of the Dirac type are established for quark-antiquark systems, each relative to the quark or to the antiquark of the system. The kernels of the bound state equations are defined through a series of Wilson loop averages along closed polygonal contours and their functional derivatives on them. A sufficient criterion for spontaneous chiral symmetry breaking is derived, relating the Goldstone boson wave function in the zero total momentum limit with the scalar part of the gauge invariant quark two-point Green's function. © 2013 American Physical Society.

Holland I.B.,University Paris - Sud
Methods in molecular biology (Clifton, N.J.) | Year: 2010

I have tried to cover the minimal properties of the prolific number of protein secretion systems identified presently, particularly in Gram negative bacteria. New systems, however, are being reported almost by the month and certainly I have missed some. With the accumulating evidence one remains in awe of the complexity of some pathways, with the Type III, IV and VI especially fearsome and impressive. These systems illustrate that protein secretion from bacteria is not only about passage of large polypeptides across a bilayer but also through long tunnels, raising quite different questions concerning mechanisms. The mechanism of transport via the Sec-translocase-translocon is well on the way to full understanding, although a structure of a stuck intermediate would be very helpful. The understanding of the precise details of the mechanism of targeting specificity, and actual polypeptide translocation in other systems is, however, far behind. Groups willing to do the difficult (and risky) work to understand mechanism should therefore be more actively encouraged, perhaps to pursue multidisciplinary, collaborative studies. In writing this review I have become fascinated by the cellular regulatory mechanisms that must be necessary to orchestrate the complex flow of so many polypeptides, targeted by different signals to such a wide variety of transporters. I have tried to raise questions about how this might be managed but much more needs to be done in this area. Clearly, this field is very much alive and the future will be full of revealing and surprising twists in the story.

Laflorencie N.,University Paris - Sud | Mila F.,Institute Of Theorie Des Phenomenes Physiques
Physical Review Letters | Year: 2011

Since the discovery of superfluidity in He4 and Landau's phenomenological theory, the relationship between Bose condensation and superfluidity has been intensely debated. He4 is known by now to be both superfluid and condensed at low temperature, and more generally, in dimension D?2, all superfluid bosonic models realized in experiments are condensed in their ground state, the most recent example being provided by ultracold bosonic atoms trapped in an optical lattice. In this Letter, it is shown that a 2D gas of bosons which is not condensed at T=0 can be achieved by populating a layer through a frustrated proximity effect from a superfluid reservoir. This condensate-free bosonic fluid is further shown to be a superfluid with incommensurate correlations. © 2011 American Physical Society.

Oberto J.,University Paris - Sud
BMC Bioinformatics | Year: 2010

Background: The binding of regulatory proteins to their specific DNA targets determines the accurate expression of the neighboring genes. The in silico prediction of new binding sites in completely sequenced genomes is a key aspect in the deeper understanding of gene regulatory networks. Several algorithms have been described to discriminate against false-positives in the prediction of new binding targets; however none of them has been implemented so far to assist the detection of binding sites at the genomic scale.Results: FITBAR (Fast Investigation Tool for Bacterial and Archaeal Regulons) is a web service designed to identify new protein binding sites on fully sequenced prokaryotic genomes. This tool consists in a workbench where the significance of the predictions can be compared using different statistical methods, a feature not found in existing resources. The Local Markov Model and the Compound Importance Sampling algorithms have been implemented to compute the P-value of newly discovered binding sites. In addition, FITBAR provides two optimized genomic scanning algorithms using either log-odds or entropy-weighted position-specific scoring matrices. Other significant features include the production of a detailed genomic context map for each detected binding site and the export of the search results in spreadsheet and portable document formats. FITBAR discovery of a high affinity Escherichia coli NagC binding site was validated experimentally in vitro as well as in vivo and published.Conclusions: FITBAR was developed in order to allow fast, accurate and statistically robust predictions of prokaryotic regulons. This feature constitutes the main advantage of this web tool over other matrix search programs and does not impair its performance. The web service is available at http://archaea.u-psud.fr/fitbar. © 2010 Oberto; licensee BioMed Central Ltd.

Naville M.,University Paris - Sud
Briefings in functional genomics | Year: 2010

Premature termination of transcription, or attenuation, is an efficient RNA-based regulatory strategy that is commonly used in bacterial organisms. Attenuators are generally located in the 50 untranslated regions of genes or operons and combine a Rho-independent terminator, controlling transcription, with an RNA element that senses specific environmental signals. A striking diversity of sensing elements enable regulation of gene expression in response to multiple environmental conditions, including temperature changes, availability of small metabolites(such as ions, amino acids, nucleobases or vitamins), or availability of macromolecules such as tRNAs and regulatory proteins. The wide distribution of attenuators suggests an early emergence among bacteria. However, attenuators also display a great mobility and lability, illustrated by a multiplicity of recent horizontal transfers and duplications.For these reasons, attenuation systems are of high interest both from a fundamental evolutionary perspective and for possible biotechnological applications.

Moreau G.,University Paris - Sud
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

First, we study the fit of the Higgs boson rates, based on all the latest collider data, in the effective framework for any extra fermion(s) (EF). The best-fit results are presented in a generic formalism allowing us to apply those for the test of any EF scenario under the assumption that the corrections to the Higgs couplings are coming exclusively from EF effects. The variations of the fit with each one of the five fundamental parameters are described, and the obtained fits can be better than in the Standard Model (SM). We show how the determination of the EF loop contributions to the Higgs couplings with photons and gluons is relying on the knowledge of the top and bottom Yukawa couplings (affected by EF mixings); for determining the latter coupling, the relevance of the investigation of the Higgs production in association with bottom quarks is emphasized. In the instructive approximation of a single EF, we find that the constraints from the fit already turn out to be quite predictive in both cases of an EF mixed or not with SM fermions, and especially when combined with the extra-quark (-lepton) mass bounds from direct EF searches at the LHC (LEP) collider. In the case of an unmixed extra quark (in the same color representation as SM quarks), nontrivial fit constraints are pointed out on the Yukawa couplings for masses up to ∼200 TeV. In particular, we define the extra dysfermiophilia, which is predicted at 68.27% C.L. for any single extra quark (independently of its electric charge). Another result is that, among any components of SM multiplet extensions, the extra quark with a -7/3 electric charge is the one preferred by the present Higgs fit. © 2013 American Physical Society.

Eggermont A.M.,University Paris - Sud
Journal of clinical oncology : official journal of the American Society of Clinical Oncology | Year: 2013

The GM2 ganglioside is an antigen expressed in the majority of melanomas. The GM2-KLH/QS-21 vaccine induces high immunoglobulin M (IgM) and IgG antibody responses. The EORTC 18961 trial compared the efficacy of GM2-KLH/QS-21 vaccination versus observation. A total of 1,314 patients with a primary tumor > 1.50 mm in thickness (T3-4N0M0; American Joint Committee on Cancer stage II) were randomly assigned to GM2-KLH/QS-21 vaccination (n = 657) or observation (n = 657). Treatment consisted of subcutaneous injections once per week from week 1 to 4, then every 3 months for the first 2 years and every 6 months during the third year. Primary end point was relapse-free survival (RFS). Secondary end points were distant metastasis-free survival (DMFS) and overall survival (OS). Analyses were by intent to treat. After a median follow-up of 1.8 years, the trial was stopped at the second interim analysis for futility regarding RFS (hazard ratio [HR], 1.00; P = .99) and detrimental outcome regarding OS (HR, 1.66; P = .02). After a median follow-up of 4.2 years, we had recorded 400 relapses, nine deaths without relapse, a total of 236 deaths. At 4 years, the vaccination arm showed a decreased RFS rate of 1.2% (HR, 1.03; 95% CI, 0.84 to 1.25) and OS rate of 2.1% (HR, 1.16; 95% CI, 0.90 to 1.51). Toxicity was acceptable, with 4.6% of patients ending study participation because of toxicity. GM2-KLH/QS-21 vaccination does not improve outcome for patients with stage II melanoma.

Poitrasson F.,Institut Universitaire de France | Delpech G.,University Paris - Sud | Gregoire M.,Institut Universitaire de France
Contributions to Mineralogy and Petrology | Year: 2013

With the aim to better understand the cause of the iron isotope heterogeneity of mantle-derived bulk peridotites, we compared the petrological, geochemical and iron isotope composition of four xenolith suites from different geodynamic settings; sub-arc mantle (Patagonia); subcontinental lithospheric mantle (Cameroon), oceanic mantle (Kerguelen) and cratonic mantle (South Africa). Although correlations were not easy to obtain and remain scattered because these rocks record successive geological events, those found between δ57Fe, Mg#, some major and trace element contents of rocks and minerals highlight the processes responsible for the Fe isotope heterogeneity. While partial melting processes only account for moderate Fe isotope variations in the mantle (<0.2 ‰, with bulk rock values yielding a range of δ57Fe ± 0.1 ‰ relative to IRMM-14), the main cause of Fe isotope heterogeneity is metasomatism (>0.9 ‰). The kinetic nature of rapid metasomatic exchanges between low viscosity melts/fluids and their wall-rocks peridotite in the mantle is the likely explanation for this large range. There are a variety of responses of Fe isotope signatures depending on the nature of the metasomatic processes, allowing for a more detailed study of metasomatism in the mantle with Fe isotopes. The current database on the iron isotope composition of peridotite xenoliths and mafic eruptive rocks highlights that most basalts have their main source deeper than the lithospheric mantle. Finally, it is concluded that due to a complex geological history, Fe isotope compositions of mantle xenoliths are too scattered to define a mean isotopic composition with enough accuracy to assess whether the bulk silicate Earth has a mean δ57Fe that is chondritic, or if it is ~0.1 ‰ above chondrites as initially proposed. © 2013 Springer-Verlag Berlin Heidelberg.

Larroche O.,CEA DAM Ile-de-France | Klisnick A.,University Paris - Sud
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2013

The amplification of high-order-harmonics (HOH) seed pulses in a swept-gain XUV laser is investigated through numerical simulations of the full set of Bloch and two-dimensional paraxial propagation equations with our code colax. The needed atomic data are taken from a hydrodynamics and collisional-radiative simulation in the case of a Ni-like Ag plasma created from the interaction of an infrared laser with a solid target and pumped in the transient regime. We show that the interplay of strong population inversion and diffraction or refraction due to the short transverse dimensions and steep density gradient of the active plasma can lead to the amplification of an intense, ultrashort, quasi-"π" pulse triggered by the incoming seed. By properly tuning the system geometry and HOH pulse parameters, we show that an â‰10 fs, 8×1012 W/cm2 amplified pulse can be achieved in a 3-mm-long Ni-like Ag plasma, with a factor of â‰10 intensity contrast with respect to the longer-lasting wake radiation and amplified spontaneous emission. © 2013 American Physical Society.

Bentz C.,University Paris - Sud
Theoretical Computer Science | Year: 2011

Given an edge-weighted (di)graph and a list of sourcesink pairs of vertices of this graph, the minimum multicut problem consists in selecting a minimum-weight set of edges (or arcs), whose removal leaves no path from each source to the corresponding sink. This is a well-known NP-hard problem, and improving several previous results, we show that it remains APX-hard in unweighted directed acyclic graphs (DAG), even with only two sourcesink pairs. This is also true if we remove vertices instead of arcs. © 2011 Elsevier B.V. All rights reserved.

Sasihithlu K.,University Paris - Sud | Narayanaswamy A.,Columbia University
Optics Express | Year: 2014

We compute near-field radiative transfer between two spheres of unequal radii R1 and R2 such that R2 . 40R1. For R2 = 40R1, the smallest gap to which we have been able to compute radiative transfer is d = 0:016R1. To accomplish these computations, we have had to modify existing methods for computing near-field radiative transfer between two spheres in the following ways: (1) exact calculations of coefficients of vector translation theorem are replaced by approximations valid for the limit d - R1, and (2) recursion relations for a normalized form of translation coefficients are derived which enable us to replace computations of spherical Bessel and Hankel functions by computations of ratios of spherical Bessel or spherical Hankel functions. The results are then compared with the predictions of the modified proximity approximation. © 2014 Optical Society of America.

Iasonos A.,Sloan Kettering Cancer Center | O'Quigley J.,University Paris - Sud
Statistics in Medicine | Year: 2012

Model-based dose-finding designs such as the continual reassessment method (CRM) rely on some basic working model. In the Bayesian setting, these take the form of 'guess estimates' of the probabilities of toxicity at each level. In the likelihood setting, these estimates simply take the form of a model as operational characteristics are unaffected by arbitrary positive power transformations. These initial estimates are often referred to as the model skeleton. The impact of any prior distribution on the model parameter that describes the dose-toxicity curve will itself depend on the skeleton being used. We study the interplay between prior assumptions and skeleton choice in the context of two-stage CRM designs. We consider the behavior of a two-stage design at the point of transition from a 3+3 design to CRM. We study how use can be made of stage1 data to construct a more efficient skeleton in conjunction with any prior information through an example of a clinical trial. We evaluate to what extent stage1 data might be down weighted when the maximum tolerated dose (MTD) is far from the starting level and stage1 data is strongly informative. The results show no improvement in accuracy; thus, weighting is not necessary unless the investigators feel strongly about the location of the MTD and wish to accelerate into the vicinity of the MTD. In general, because this information is not available, we recommend that the design of two-stage trials utilize stage1 data to establish a skeleton. © 2012 John Wiley & Sons, Ltd.

De Medici L.,University Pierre and Marie Curie | De Medici L.,University Paris - Sud | De Medici L.,European Synchrotron Radiation Facility | Giovannetti G.,International School for Advanced Studies | Capone M.,International School for Advanced Studies
Physical Review Letters | Year: 2014

We show that electron- and hole-doped BaFe2As2 are strongly influenced by a Mott insulator that would be realized for half-filled conduction bands. Experiments show that weakly and strongly correlated conduction electrons coexist in much of the phase diagram, a differentiation which increases with hole doping. This selective Mottness is caused by the Hund's coupling effect of decoupling the charge excitations in different orbitals. Each orbital then behaves as a single-band doped Mott insulator, where the correlation degree mainly depends on how doped is each orbital from half filling. Our scenario reconciles contrasting evidences on the electronic correlation strength, implies a strong asymmetry between hole and electron doping, and establishes a deep connection with the cuprates. © 2014 American Physical Society.

Fizazi K.S.,University Paris - Sud
Journal of clinical oncology : official journal of the American Society of Clinical Oncology | Year: 2013

PURPOSE As part of the ENTHUSE (Endothelin A Use) program, the efficacy and safety of zibotentan (ZD4054), an oral specific endothelin A receptor antagonist, has been investigated in combination with docetaxel in patients with metastatic castration-resistant prostate cancer (CRPC). PATIENTS AND METHODS In this randomized, double-blind, placebo-controlled, phase III study, patients received intravenous docetaxel 75 mg/m(2) on day 1 of 21-day cycles plus oral zibotentan 10 mg or placebo once daily. The primary end point was overall survival (OS). Secondary end points included time to pain and prostate-specific antigen (PSA) progression, pain and PSA response, progression-free survival, health-related quality of life, and safety. Results A total of 1,052 patients received study treatment (docetaxel-zibotentan, n = 524; docetaxel-placebo, n = 528). At the time of data cutoff, there had been 277 and 280 deaths, respectively. There was no difference in OS for patients receiving docetaxel-zibotentan compared with those receiving docetaxel-placebo (hazard ratio, 1.00; 95% CI, 0.84 to 1.18; P = .963). No significant differences were observed on secondary end points, including time to pain progression (median 9.3 v 10.0 months, respectively) or pain response (odds ratio, 0.84; 95% CI, 0.61 to 1.16; P = .283). The median time to death was 20.0 and 19.2 months for the zibotentan and placebo groups, respectively. The most commonly reported adverse events in zibotentan-treated patients were peripheral edema (52.7%), diarrhea (35.4%), alopecia (33.9%), and nausea (33.3%). CONCLUSION Docetaxel plus zibotentan 10 mg/d did not result in a significant improvement in OS compared with docetaxel plus placebo in patients with metastatic CRPC.

Janin J.,University Paris - Sud
Protein Science | Year: 2014

A minimal model of protein-protein binding affinity that takes into account only two structural features of the complex, the size of its interface, and the amplitude of the conformation change between the free and bound subunits, is tested on the 144 complexes of a structure-affinity benchmark. It yields Kd values that are within two orders of magnitude of the experiment for 67% of the complexes, within three orders for 88%, and fails on 12%, which display either large conformation changes, or a very high or a low affinity. The minimal model lacks the specificity and accuracy needed to make useful affinity predictions, but it should help in assessing the added value of parameters used by more elaborate models, and set a baseline for evaluating their performances. © 2014 The Protein Society.

Valderrama M.P.,University Paris - Sud | Phillips D.,Ohio University
Physical Review Letters | Year: 2015

We analyze the power counting of two-body currents in nuclear effective field theories (EFTs). We find that the existence of nonperturbative physics at low energies, which is manifest in the existence of the deuteron and the S01 NN virtual bound state, combined with the appearance of singular potentials in versions of nuclear EFT that incorporate chiral symmetry, modifies the renormalization-group flow of the couplings associated with contact operators that involve nucleon-nucleon pairs and external fields. The order of these couplings is thereby enhanced with respect to the naive-dimensional-analysis estimate. Consequently, short-range currents enter at a lower order in the chiral EFT than has been appreciated up until now, and their impact on low-energy observables is concomitantly larger. We illustrate the changes in the power counting with a few low-energy processes involving external probes and few-nucleon systems, including electron-deuteron elastic scattering and radiative neutron capture by protons. © 2015 American Physical Society.

Petrov D.S.,University Paris - Sud
Physical Review Letters | Year: 2015

According to the mean-field theory a condensed Bose-Bose mixture collapses when the interspecies attraction becomes stronger than the geometrical average of the intraspecies repulsions, g122>g11g22. We show that instead of collapsing such a mixture gets into a dilute liquidlike droplet state stabilized by quantum fluctuations thus providing a direct manifestation of beyond mean-field effects. We study various properties of the droplet and find, in particular, that in a wide range of parameters its excitation spectrum lies entirely above the particle emission threshold. The droplet thus automatically evaporates itself to zero temperature, the property potentially interesting by itself and from the viewpoint of sympathetic cooling of other systems. © 2015 American Physical Society.

Dudas E.,Ecole Polytechnique - Palaiseau | Mambrini Y.,University Paris - Sud | Olive K.A.,University of Minnesota
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

We study a minimal extension of the Standard Model where a scalar field is coupled to the right-handed neutrino responsible for the seesaw mechanism for neutrino masses. In the absence of other couplings, below 8 TeV the scalar A has a unique decay mode A→νν, ν being the physical observed light neutrino state. Above 8 TeV (11 TeV), the 3-body (4-body) decay modes dominate. Imposing constraints on neutrino masses mν from atmospheric and solar experiments implies a long lifetime for A, much larger than the age of the Universe, making it a natural dark matter candidate. Its lifetime can be as large as 1029seconds, and its signature below 8 TeV would be a clear monochromatic neutrino signal, which can be observed by ANTARES or IceCube. Under certain conditions, the scalar A may be viewed as a Goldstone mode of a complex scalar field whose vacuum expectation value generates the Majorana mass for νR. In this case, we expect the dark matter scalar to have a mass 10GeV. © 2015 American Physical Society.

Bontemps D.,University Paris - Sud
IEEE Transactions on Information Theory | Year: 2011

This paper deals with the problem of universal lossless coding on a countable infinite alphabet. It focuses on some classes of sources defined by an envelope condition on the marginal distribution, namely exponentially decreasing envelope classes with exponent α. The minimax redundancy of exponentially decreasing envelope classes is proved to be equivalent to 1/4 α log e log2 n. Then, an adaptive algorithm is proposed, whose maximum redundancy is equivalent to the minimax redundancy. © 2011 IEEE.

Sauquet H.,University Paris - Sud
Comptes Rendus - Palevol | Year: 2013

Molecular dating has now become a common tool for many biologists and considerable methodological improvements have been made over the last few years. However, the practice of estimating divergence times using molecular data is highly variable among researchers and it is not straightforward for a newcomer to the field to know how to start. Here I provide a brief overview of the current state-of-the-art of molecular dating practice. I review some of the important choices that must be made when conducting a divergence time analysis, including how to select and use calibrations and which relaxed clock model and program to use, with a focus on some practical aspects. I then provide some guidelines for the interpretation of results and briefly review some alternatives to molecular dating for obtaining divergence times. Last, I present some promising developments for the future of the field, related to the improvement of the calibration process. © 2013 Académie des sciences.

Chailloux A.,University Paris - Sud | Kerenidis I.,University Paris Diderot
Proceedings - Annual IEEE Symposium on Foundations of Computer Science, FOCS | Year: 2011

Bit commitment is a fundamental cryptographic primitive with numerous applications. Quantum information allows for bit commitment schemes in the information theoretic setting where no dishonest party can perfectly cheat. The previously best-known quantum protocol by Ambainis achieved a cheating probability of at most 3/4 [Amb01]. On the other hand, Kitaev showed that no quantum protocol can have cheating probability less than 1√2 [Kit03] (his lower bound on coin flipping can be easily extended to bit commitment). Closing this gap has since been an important open question. In this paper, we provide the optimal bound for quantum bit commitment. First, we show a lower bound of approximately 0.739, improving Kitaev's lower bound. For this, we present some generic cheating strategies for Alice and Bob and conclude by proving a new relation between the trace distance and fidelity of two quantum states. Second, we present an optimal quantum bit commitment protocol which has cheating probability arbitrarily close to 0.739. More precisely, we show how to use any weak coin flipping protocol with cheating probability 1/2 + ε in order to achieve a quantum bit commitment protocol with cheating probability 0.739 + O(ε). We then use the optimal quantum weak coin flipping protocol described by Mochon [Moc07]. Last, in order to stress the fact that our protocol uses quantum effects beyond the weak coin flip, we show that any classical bit commitment protocol with access to perfect weak (or strong) coin flipping has cheating probability at least 3/4. © 2011 IEEE.

Lansberg J.-P.,University Paris - Sud | Shao H.-S.,CERN
Nuclear Physics B | Year: 2015

We present predictions for double-quarkonium production in the kinematical region relevant for the proposed fixed-target experiment using the LHC beams (dubbed as AFTER@LHC). These include all spin-triplet S-wave charmonium and bottomonium pairs, i.e. ψ(n1S)+ψ(n2S), ψ(n1S)+ϒ{hooked}(m1S) and ϒ{hooked}(m1S)+ϒ{hooked}(m2S) with n1, n2=1, 2 and m1, m2=1, 2, 3. We calculate the contributions from double-parton scatterings and single-parton scatterings. With an integrated luminosity of 20 fb-1 to be collected at AFTER@LHC, we find that the yields for double-charmonium production are large enough for differential distribution measurements. We discuss some differential distributions for J/ψ+J/ψ production, which can help to study the physics of double-parton and single-parton scatterings in a new energy range and which might also be sensitive to double intrinsic cc- coalescence at large negative Feynman x. © 2015 The Authors.

Toma T.,University Paris - Sud
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2015

Gamma-rays induced by annihilation or decay of dark matter can be its smoking gun signature. In particular, gamma-rays generated by internal bremsstrahlung of Majorana and real scalar dark matter is promising since it can be a leading emission of sharp gamma-rays. However in the case of Majorana dark matter, its cross section for internal bremsstrahlung cannot be large enough to be observed by future gamma-ray experiments if the observed relic density is assumed to be thermally produced. In this paper, we introduce some degenerate particles with Majorana dark matter, and show they lead enhancement of the cross section. As a result, increase of about one order of magnitude for the cross section is possible without conflict with the observed relic density, and it would be tested by the future gamma-ray experiments such as GAMMA-400 and Cherenkov Telescope Array (CTA). In addition, the constraints of perturbativity, positron observation by the AMS experiment and direct search for dark matter are discussed. © 2015 The Authors.

Bensadon J.,University Paris - Sud
Entropy | Year: 2015

Information geometric optimization (IGO) is a general framework for stochastic optimization problems aiming at limiting the influence of arbitrary parametrization choices: the initial problem is transformed into the optimization of a smooth function on a Riemannian manifold, defining a parametrization-invariant first order differential equation and, thus, yielding an approximately parametrization-invariant algorithm (up to second order in the step size). We define the geodesic IGO update, a fully parametrization-invariant algorithm using the Riemannian structure, and we compute it for the manifold of Gaussians, thanks to Noether's theorem. However, in similar algorithms, such as CMA-ES (Covariance Matrix Adaptation - Evolution Strategy) and xNES (exponential Natural Evolution Strategy), the time steps for the mean and the covariance are decoupled. We suggest two ways of doing so: twisted geodesic IGO (GIGO) and blockwise GIGO. Finally, we show that while the xNES algorithm is not GIGO, it is an instance of blockwise GIGO applied to the mean and covariance matrix separately. Therefore, xNES has an almost parametrization-invariant description. © 2015 by the author.

Sanchez-Palencia L.,University Paris - Sud | Lewenstein M.,Catalan Institution for Research and Advanced Studies
Nature Physics | Year: 2010

When attempting to understand the role of disorder in condensed-matter physics, we face considerable experimental and theoretical difficulties, and many questions are still open. Two of the most challenging onesdebated for decadesconcern the effect of disorder on superconductivity and quantum magnetism. We review recent progress in the field of ultracold atomic gases, which should pave the way towards the realization of versatile quantum simulators, which help solve these questions. In addition, ultracold gases offer original practical and conceptual approaches, which open new perspectives to the field of disordered systems. © 2010 Macmillan Publishers Limited. All rights reserved.

Tcherkez G.,University Paris - Sud | Tcherkez G.,Institut Universitaire de France
Plant, Cell and Environment | Year: 2013

Although ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) was discovered nearly 60 years ago, the associated chemical mechanism of the reaction is still incompletely understood. The catalytic cycle consists of four major steps: ribulose-1,5-bisphosphate binding, enolization, CO2 or O2 addition and hydration, and cleavage of the intermediate. The use of individual rate constants for these elemental steps yields mathematical expressions for usual kinetic constants (kcat, Km), CO2 versus O2 specificity (Sc/o) as well as other chemical parameters such as the 12C/13C isotope effect. That said, most of them are not simple and thus the interpretation of experimental and observed values of kcat, Km and Sc/o may be more complicated than expected. That is, Rubisco effective catalysis depends on several kinetic parameters that are influenced by both the biological origin and the cellular medium (which, in turn, can vary with environmental conditions). In this brief review, we present the basic model of Rubisco kinetics and describe how subtle biochemical changes (which may have occurred along Evolution) can easily modify Rubisco catalysis. The chemical mechanism of Rubisco is at the heart of photosynthetic metabolism since it dictates the rate of carboxylation. Here, advantage is taken of chemical formalism to give general equations describing carboxylation velocity, specificity and isotope effects. The limits of these and uncertainties on intrinsic chemical events are discussed so as to appreciate possibilities of optimization. © 2013 John Wiley & Sons Ltd.

Bogdanos C.,University Paris - Sud | Saridakis E.N.,National and Kapodistrian University of Athens
Classical and Quantum Gravity | Year: 2010

We investigate the scalar and tensor perturbations in Hoava gravity, with and without detailed balance, around a flat background. Once both types of perturbations are taken into account, it is revealed that the theory is plagued by ghost-like scalar instabilities in the range of parameters which would render it power-counting renormalizable, that cannot be overcome by simple tricks such as analytic continuation. Implementing a consistent flow between the UV and IR limits seems thus more challenging than initially presumed, regardless of whether the theory approaches general relativity at low energies or not. Even in the phenomenologically viable parameter space, the tensor sector leads to additional potential problems, such as fine-tunings and super-luminal propagation. © 2010 IOP Publishing Ltd.

Charmousis C.,University Paris - Sud
Lecture Notes in Physics | Year: 2015

We review and discuss some recent progress in Lovelock and Horndeski theories modifying Einstein’s General Relativity. Using as our guide the uniqueness properties of these modified gravity theories we then discuss how Kaluza-Klein reduction of Lovelock theory can lead to effective scalar-tensor actions including several important terms of Horndeski theory. We show how this can be put to practical use by mapping analytic black hole solutions of one theory to the other. We then elaborate on the subset of Horndeski theory that has self-tuning properties and review a generic method giving scalar-tensor black hole solutions. © Springer International Publishing Switzerland 2015.

Bergeron H.,University Paris - Sud | Gazeau J.P.,Brazilian Center for Research in Physics (CBPF) | Gazeau J.P.,University Paris Diderot
Annals of Physics | Year: 2014

The paper concerns integral quantization, a procedure based on operator-valued measure and resolution of the identity. We insist on covariance properties in the important case where group representation theory is involved. We also insist on the inherent probabilistic aspects of this classical-quantum map. The approach includes and generalizes coherent state quantization. Two applications based on group representation are carried out. The first one concerns the Weyl-Heisenberg group and the euclidean plane viewed as the corresponding phase space. We show that a world of quantizations exist, which yield the canonical commutation rule and the usual quantum spectrum of the harmonic oscillator. The second one concerns the affine group of the real line and gives rise to an interesting regularization of the dilation origin in the half-plane viewed as the corresponding phase space. © 2014 Elsevier Inc.

Lorce C.,University Paris - Sud | Lorce C.,University of Liege
Nuclear Physics A | Year: 2014

Exploring the similarities between the Chen et al. approach, where physical and gauge degrees of freedom of the gauge potential are explicitly separated, and the background field method, we provide an alternative point of view to the proton spin decomposition issue. We show in particular that the gauge symmetry can be realized in two different ways, and discuss the relations between the concepts of path dependence, Stueckelberg dependence and background dependence. Finally, we argue that path/Stueckelberg/background-dependent decompositions of the proton spin are in principle measurable and therefore physically meaningful. © 2014 Elsevier B.V.

Veyrac A.,University of Liege | Veyrac A.,University Paris - Sud | Bakker J.,University of Liege
FASEB Journal | Year: 2011

Neurons incorporated into the adult main olfactory bulb (MOB) and accessory olfactory bulb (AOB) derive from the subventricular zone (SVZ). Despite some recent studies on the role of olfactory neurogenesis in sociosexual behaviors mediated by hormones, data on the implication of estrogens are still lacking. Taking advantage of female aromatase-knockout (ArKO) mice, which are unable to produce estradiol across their life span, we investigated the role of estradiol exposure during early postnatal and adult periods on adult neurogenesis in the MOB and AOB. We found that proliferation of progenitor cells in the adult female SVZ was not influenced by estradiol. However, whereas adult exposure to estradiol influences the turnover of MOB newborn neurons, the survival of those in the AOB depends on exposure to estradiol during the early postnatal period. Finally, based on their expression of Zif268, we showed that newborn neurons in the MOB responded to sociosexual odors, albeit to a lesser extent in ArKO females, suggesting a contribution of estradiol during the early postnatal period to this response. Together, these results suggest that the survival and functional integration of newborn neurons in the adult female MOB and AOB are differentially influenced by estrogens from the early postnatal period to adulthood. © FASEB.

Jacquet M.,University Paris - Sud
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | Year: 2014

Thanks to the exceptional development of high power femtosecond lasers in the last 15 years, Compton based X-ray sources are in full development over the world in the recent years. Compact Compton sources are able to combine the compactness of the instrument with a beam of high intensity, high quality, tunable in energy. In various fields of applications such as biomedical science, cultural heritage preservation and material science researches, these sources should provide an easy working environment and the methods currently used at synchrotrons could be largely developed in a lab-size environment as hospitals, labs, or museums. © 2014 Elsevier B.V. All rights reserved.

Lorce C.,University Paris - Sud | Lorce C.,University of Liege
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014

We investigate the correlations between the quark spin and orbital angular momentum inside the nucleon. Similarly to the Ji relation, we show that these correlations can be expressed in terms of specific moments of measurable parton distributions. This provides a whole new piece of information about the partonic structure of the nucleon. © 2014.

Robinet F.,University Paris - Sud
Classical and Quantum Gravity | Year: 2010

In July 2009, Virgo started its second Science Run (VSR2) jointly with the LIGO detectors (S6). Great efforts have been made to understand the new sources of noise disturbance inVirgo data due to the detector or its environment. This understanding is crucial in order to reject noise events that could mimic a genuine gravitational wave (GW). One of the great challenges of VSR2 was to be able to monitor and deliver data quality information with low latency so that the online burst and inspiral GW searches could generate event candidates for follow-up studies. This paper reviews the sources of noise which have been identified and explains how it was possible to discard the associated noise events from the data. Finally, it presents the effect of data quality vetoes on Virgo triggers. © 2010 IOP Publishing Ltd.

Efrati A.,Weizmann Institute of Science | Falkowski A.,University Paris - Sud | Soreq Y.,Weizmann Institute of Science
Journal of High Energy Physics | Year: 2015

Abstract: We derive model-independent constraints arising from the Z and W boson observables on dimension six operators in the effective theory beyond the Standard Model. In particular, we discuss the generic flavor structure for these operators as well as several flavor patterns motivated by simple new physics scenarios. © 2015, The Author(s).

Rivasseau V.,University Paris - Sud
Fortschritte der Physik | Year: 2014

We provide an informal up-to-date review of the tensor track approach to quantum gravity. In a long introduction we describe in simple terms the motivations for this approach. Then the many recent advances are summarized, with emphasis on some points (Gromov-Hausdorff limit, Loop vertex expansion, Osterwalder-Schrader positivity..) which, while important for the tensor track program, are not detailed in the usual quantum gravity literature. We list open questions in the conclusion and provide a rather extended bibliography. The author provides an informal up-to-date review of the tensor track approach to quantum gravity. Many recent advances are summarized with emphasis on some rarely discussed points such as the Gromov-Hausdorff limit, the loop vertex expansion, the Osterwalder-Schrader positivity. Open questions and a rather extended bibliography are provided. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Carbonell J.,University Paris - Sud | Karmanov V.A.,RAS Lebedev Physical Institute
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2016

We show that the Bethe-Salpeter equation for the scattering amplitude in the limit of zero incident energy can be transformed into a purely Euclidean form, as it is the case for the bound states. The decoupling between Euclidean and Minkowski amplitudes is only possible for zero energy scattering observables and allows determining the scattering length from the Euclidean Bethe-Salpeter amplitude. Such a possibility strongly simplifies the numerical solution of the Bethe-Salpeter equation and suggests an alternative way to compute the scattering length in Lattice Euclidean calculations without using the Luscher formalism. The derivations contained in this work were performed for scalar particles and one-boson exchange kernel. They can be generalized to the fermion case and more involved interactions. © 2016 The Authors.

The main content of this review article is first to review the main inference tools using Bayes rule, the maximum entropy principle (MEP), information theory, relative entropy and the Kullback-Leibler (KL) divergence, Fisher information and its corresponding geometries. For each of these tools, the precise context of their use is described. The second part of the paper is focused on the ways these tools have been used in data, signal and image processing and in the inverse problems, which arise in different physical sciences and engineering applications. A few examples of the applications are described: entropy in independent components analysis (ICA) and in blind source separation, Fisher information in data model selection, different maximum entropy-based methods in time series spectral estimation and in linear inverse problems and, finally, the Bayesian inference for general inverse problems. Some original materials concerning the approximate Bayesian computation (ABC) and, in particular, the variational Bayesian approximation (VBA) methods are also presented. VBA is used for proposing an alternative Bayesian computational tool to the classical Markov chain Monte Carlo (MCMC) methods. We will also see that VBA englobes joint maximum a posteriori (MAP), as well as the different expectation-maximization (EM) algorithms as particular cases. © 2015 by the authors.

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.

I theoretically study the behavior of strong pulses exciting emitters inside a cavity. The ensemble is supposed to be inhomogeneously broadened and the cavity matched finding application in quantum storage of optical or RF photons. My analysis is based on energy and pulse area conservation rules predicting important distortions for specific areas. It is well supported by numerical simulations. I propose a qualitative interpretation in terms of slow-light. The analogy with the free space situation is remarkable. © 2014 Optical Society of America.

Reddy L.H.,Sanofi S.A. | Couvreur P.,University Paris - Sud
Journal of Hepatology | Year: 2011

Nanotechnology has been considered for the improved delivery of various therapeutic agents, including drugs and genes. Indeed, liposomes and nanoparticles equipped with homing devices for the targeting of receptors over-expressed on the hepatic tissue have improved the treatment of various liver diseases. In this review, various nanotechnology approaches employed for the treatment/imaging of liver disease, either in preclinical or in clinic are discussed. © 2011 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

Aleiner I.L.,Columbia University | Altshuler B.L.,Columbia University | Shlyapnikov G.V.,University Paris - Sud | Shlyapnikov G.V.,University of Amsterdam
Nature Physics | Year: 2010

It is commonly accepted that there are no phase transitions in one-dimensional systems at a finite temperature, because long-range correlations are destroyed by thermal fluctuations. Here we show theoretically that the one-dimensional gas of short-range interacting bosons in the presence of disorder can undergo a finite-temperature phase transition between two distinct states: fluid and insulator. Neither of these states has long-range spatial correlations, but this is a true, albeit non-conventional, phase transition, because transport properties are singular at the transition point. In the fluid phase, mass transport is possible, whereas in the insulator phase it is completely blocked even at finite temperatures. This study thus provides insight into how the interaction between disordered bosons influences their Anderson localization. This question, first raised for electrons in solids, is now crucial for the studies of atomic bosons, where recent experiments have demonstrated Anderson localization in expanding dilute quasi-one-dimensional clouds. © 2010 Macmillan Publishers Limited. All rights reserved.

Lebedev O.,Helsinki Institute of Physics | Mambrini Y.,University Paris - Sud
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014

We consider the possibility that fermionic dark matter (DM) interacts with the Standard Model fermions through an axial Z' boson. As long as Z' decays predominantly into dark matter, the relevant LHC bounds are rather loose. Direct dark matter detection does not significantly constrain this scenario either, since dark matter scattering on nuclei is spin-dependent. As a result, for a range of the Z' mass and couplings, the DM annihilation cross section is large enough to be consistent with thermal history of the Universe. In this framework, the thermal WIMP paradigm, which currently finds itself under pressure, is perfectly viable. © 2014 The Authors.

Lenz M.,University Paris - Sud
Physical Review X | Year: 2014

Movement within eukaryotic cells largely originates from localized forces exerted by myosin motors on scaffolds of actin filaments. Although individual motors locally exert both contractile and extensile forces, large actomyosin structures at the cellular scale are overwhelmingly contractile, suggesting that the scaffold serves to favor contraction over extension. While this mechanism is well understood in highly organized striated muscle, its origin in disordered networks such as the cell cortex is unknown. Here, we develop a mathematical model of the actin scaffold's local two- or three-dimensional mechanics and identify four competing contraction mechanisms. We predict that one mechanism dominates, whereby local deformations of the actin break the balance between contraction and extension. In this mechanism, contractile forces result mostly from motors plucking the filaments transversely rather than buckling them longitudinally. These findings shed light on recent in vitro experiments and provide a new geometrical understanding of contractility in the myriad of disordered actomyosin systems found in vivo.

Lafleur T.,University Paris - Sud
Plasma Sources Science and Technology | Year: 2015

Unequal areas of the powered and grounded electrodes in single-frequency capacitively coupled plasmas (CCPs) are well-known to generate a DC self-bias voltage and an asymmetric plasma response. By instead applying non-sinusoidal waveforms composed of multiple harmonics - referred to in the literature as arbitrary waveforms, multi-harmonic waveforms or tailored waveforms - an asymmetric plasma response and a DC self-bias can also be produced; even for perfectly geometrically symmetric systems. This electrical asymmetry effect (EAE) has opened the doors to a wide range of novel ideas and interesting new physics that could allow limitations between the control of the ion flux and ion energy in traditional CCPs to be broken; thus helping to develop next-generation industrial plasma processing reactors. This review is dedicated to the current status of the EAE, and highlights important theoretical, numerical and experimental work in the field that has contributed to our understanding. © 2016 IOP Publishing Ltd.

Falkowski A.,University Paris - Sud | Gross C.,Helsinki Institute of Physics | Lebedev O.,Helsinki Institute of Physics
Journal of High Energy Physics | Year: 2015

Abstract: In the Higgs portal framework, the Higgs field generally mixes with the Standard Model (SM) singlet leading to the existence of two states, one of which is identified with the 125 GeV scalar observed at the LHC. In this work, we analyse direct and indirect constraints on the second mass eigenstate and the corresponding mixing angle. The existence of the additional scalar can be beneficial as it can stabilise the otherwise-metastable electroweak vacuum. We find parameter regions where all of the bounds, including the stability constraints, are satisfied. We also study prospects for observing the decay of the heavier state into a pair of the 125 GeV Higgs-like scalars. © 2015, The Author(s).

Beguin F.,University Paris - Sud
Classical and Quantum Gravity | Year: 2010

We study the asymptotic behavior of vacuum Bianchi type A spacetimes close to their singularity. It has been conjectured that this behavior is driven by a certain circle map, called the Kasner map. As a step toward this conjecture, we prove that some orbits of the Kasner map do indeed attract some solutions of the system of ODEs which describes the behavior of vacuum Bianchi type A spacetimes. The orbits of the Kasner map for which we can prove such a result are those which are not periodic and do not accumulate on any periodic orbit. This shows the existence of Bianchi spacetimes with aperiodic oscillatory asymptotic behavior. © 2010 IOP Publishing Ltd.

Langevin D.,University Paris - Sud
Annual Review of Fluid Mechanics | Year: 2014

When surfactants adsorb at liquid surfaces, they not only decrease the surface tension, they also confer rheological properties to the surfaces. The most common rheological parameters are the surface compression elasticity and viscosity and the surface shear viscosity. These parameters usually depend on the timescale of the deformation, owing to surface relaxations, and on its amplitude, owing to nonlinear responses. In addition, surfactants can exchange between the bulk and surface, in a way that depends on the amount of bulk surfactant locally available. This complexity explains why the topic has progressed slowly over the years. This review describes the current knowledge, focusing on recent advances, and gives examples of phenomena in which surface rheology plays an important role. Copyright © 2014 by Annual Reviews. All rights reserved.

Petrov D.S.,University Paris - Sud
Physical Review Letters | Year: 2014

We propose a method of controlling two- and three-body interactions in an ultracold Bose gas in any dimension. The method requires us to have two coupled internal single-particle states split in energy such that the upper state is occupied virtually but amply during collisions. By varying system parameters, one can switch off the two-body interaction while maintaining a strong three-body one. The mechanism can be implemented for dipolar bosons in the bilayer configuration with tunneling or in an atomic system by using radio-frequency fields to couple two hyperfine states. One can then aim to observe a purely three-body interacting gas, dilute self-trapped droplets, the paired superfluid phase, Pfaffian state, and other exotic phenomena. © 2014 American Physical Society.

We perform a combined analysis of τ → Kπν τ decay and πK scattering with constraints from K ℓ3 data using a N/D approach that fulfills requirements from unitarity and analyticity. We obtain a good fit of the I = 1/2 πK amplitude in the P wave using the LASS data above the elastic region while in this region data are generated via Monte Carlo using the FOCUS results based on D ℓ4 decay. The spectrum and branching ratio of τ → Kπν τ constrained by K ℓ3 decays are also well reproduced leading to f +(0)|V us | = 0.2163±0.0014. Furthermore, we obtain the slope of the vector form factor λ + = (25.56 ± 0.40) × 10-3 while the value of the scalar form factor at the Callan-Treiman point is ln C = 0.2062 ± 0.0089. Given the experimental precision our results are compatible with the Standard Model. © 2014 The Author(s).

Dobigeon N.,National Polytechnic Institute of Toulouse | Brun N.,University Paris - Sud
Ultramicroscopy | Year: 2012

Recent advances in detectors and computer science have enabled the acquisition and the processing of multidimensional datasets, in particular in the field of spectral imaging. Benefiting from these new developments, Earth scientists try to recover the reflectance spectra of macroscopic materials (e.g., water, grass, mineral types) present in an observed scene and to estimate their respective proportions in each mixed pixel of the acquired image. This task is usually referred to as spectral mixture analysis or spectral unmixing (SU). SU aims at decomposing the measured pixel spectrum into a collection of constituent spectra, called endmembers, and a set of corresponding fractions (abundances) that indicate the proportion of each endmember present in the pixel. Similarly, when processing spectrum-images, microscopists usually try to map elemental, physical and chemical state information of a given material. This paper reports how a SU algorithm dedicated to remote sensing hyperspectral images can be successfully applied to analyze spectrum-image resulting from electron energy-loss spectroscopy (EELS). SU generally overcomes standard limitations inherent to other multivariate statistical analysis methods, such as principal component analysis (PCA) or independent component analysis (ICA), that have been previously used to analyze EELS maps. Indeed, ICA and PCA may perform poorly for linear spectral mixture analysis due to the strong dependence between the abundances of the different materials. One example is presented here to demonstrate the potential of this technique for EELS analysis. © 2012 Elsevier B.V.

Minoux M.,University Paris - Sud
Journal of Global Optimization | Year: 2011

We investigate here the class-denoted R-LP-RHSU-of two-stage robust linear programming problems with right-hand-side uncertainty. Such problems arise in many applications e.g: robust PERT scheduling (with uncertain task durations); robust maximum flow (with uncertain arc capacities); robust network capacity expansion problems; robust inventory management; some robust production planning problems in the context of power production/distribution systems. It is shown that such problems can be formulated as large scale linear programs with associated nonconvex separation subproblem. A formal proof of strong NP-hardness for the general case is then provided, and polynomially solvable subclasses are exhibited. Differences with other previously described robust LP problems (featuring row-wise uncertainty instead of column wise uncertainty) are highlighted. © 2011 Springer Science+Business Media, LLC.

Gopalaiah K.,University of Delhi | Kagan H.B.,University Paris - Sud
Chemical Record | Year: 2013

In the early eighties, we introduced samarium diiodide for the transformation of various functional groups. Since then, this reducing agent has been extensively used for the reductive cleavage of single bonds, C-C bond formations, C-N bond formations, and β-elimination reactions. In this Personal Account, we highlight our initial results, as well as some of the contributions from various research groups. Because of space limitations, we arbitrarily select some useful results that have recently been described in literature. Copyright © 2013 The Chemical Society of Japan and Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Delpech S.,University Paris - Sud
Pure and Applied Chemistry | Year: 2013

Molten salts (MSs) such as fluoride or chloride salts at high temperature (400-800 °C) are solvents known for their high solvation power and electroactivity range. Rare earths, lanthanides, actinides, and refractory metals can be dissolved, treated, and purified in MSs. The properties of these solvents are particularly interesting for nuclear spent-fuel reprocessing. The pyrochemical separation and extraction of solutes can be performed using several methods taking into account the effects of redox and/or acidity. This paper is focused on the reductive extraction method performed by contacting a liquid metal (LM) containing reductive species and an MS. The analytical model developed to calculate the efficiency of such a method is detailed in this paper. To apply this model, one essential point is the establishment of a database related to the redox and solvation properties of solutes in MSs. The approach retained to propose a database based on the analysis of both thermo-chemical data of pure compounds and experimental measurements reported in the literature is described in this paper in the case of lanthanides in fluoride MSs. The use of the database to calculate efficiency as a function of process parameters is given in this paper as well as the comparison between two reducing agents considered. © 2012 IUPAC.

Chiavarino B.,University of Rome La Sapienza | Crestoni M.E.,University of Rome La Sapienza | Fornarini S.,University of Rome La Sapienza | Scuderi D.,University Paris - Sud | Salpin J.-Y.,CNRS Laboratory for Analysis and Modelling for Biology and Environment
Journal of the American Chemical Society | Year: 2013

Infrared multiple photon dissociation (IRMPD) spectroscopy of cis-[Pt(NH3)2(G)Cl]+ and cis-[Pt(NH 3)2(A)Cl]+ ions (where A is adenine and G is guanine) has been performed in two spectral regions, 950-1900 and 2900-3700 cm-1. Quantum chemical calculations at the B3LYP/LACV3P/6-311G* level yield the optimized geometries and IR spectra for the conceivable isomers of cis-[Pt(NH3)2(G)Cl]+ and cis-[Pt(NH 3)2(A)Cl]+, whereby the cisplatin residue is attached to the N7, N3, or carbonyl oxygen atom, (O6), of guanine and to the N7, N3, or N1 position of adenine, respectively. In addition to the conventional binding sites of native adenine, complexes with N7-H tautomers have also been considered. In agreement with computational results, the IR characterization of cis-[Pt(NH3)2(G)Cl]+ points to a covalent structure where Pt is bound to the N7 atom of guanine. The characterized conformer has a hydrogen-bonding interaction between a hydrogen atom of one NH3 ligand and the carbonyl group of guanine. The experimental C-O stretching feature of cis-[Pt(NH3)2(G)Cl]+ at 1718 cm-1, remarkably red-shifted with respect to an unperturbed C-O stretching mode, is indicative of a lengthened CO bond in guanine, a signature that this group is involved in hydrogen bonding. The IRMPD spectra of cis-[Pt(NH3)2(A)Cl]+ are consistent with the presence of two major isomers, PtAN3 and PtAN1, where Pt is bound to the N3 and N1 positions of native adenine, respectively. © 2012 American Chemical Society.

Josuat-Verges M.,University Paris - Sud
Electronic Journal of Combinatorics | Year: 2011

We consider a partially asymmetric exclusion process (PASEP) on a finite number of sites with open and directed boundary conditions. Its partition function was calculated by Blythe, Evans, Colaiori, and Essler. It is known to be a generating function of permutation tableaux by the combinatorial interpretation of Corteel and Williams. We prove bijectively two new combinatorial interpretations. The first one is in terms of weighted Motzkin paths called Laguerre histories and is obtained by refining a bijection of Foata and Zeilberger. Secondly we show that this partition function is the generating function of permutations with respect to right-to-left minima, right-to-left maxima, ascents, and 31-2 patterns, by refining a bijection of Fraņcon and Viennot. Then we give a new formula for the partition function which generalizes the one of Blythe & al. It is proved in two combinatorial ways. The first proof is an enumeration of lattice paths which are known to be a solution of the Matrix Ansatz of Derrida & al. The second proof relies on a previous enumeration of rook placements, which appear in the combinatorial interpretation of a related normal ordering problem. We also obtain a closed formula for the moments of Al-Salam-Chihara polynomials.

Moller A.P.,University Paris - Sud | Moller A.P.,Center for Advanced Study
Journal of Evolutionary Biology | Year: 2010

Animals fleeing a potential predator can escape horizontally or vertically, although vertical flight is more expensive than horizontal flight. The ability to escape in three dimensions by flying animals has been hypothesized to result in greater survival and eventually slower senescence than in animals only fleeing in two dimensions. In a comparative study of flight initiation distance in 69 species of birds when approached by a human, I found that the amount of variance explained by flight initiation distance was more than four times as large for the horizontal than the vertical component of perch height when taking flight. The slope of the relationship between horizontal distance and flight initiation distance (horizontal slope) increased with increasing body mass across species, whereas the slope of the relationship between vertical distance and flight initiation distance (vertical slope) decreased with increasing body mass. Therefore, there was a negative relationship between horizontal and vertical slope, although this negative relationship was significantly less steep than expected for a perfect trade-off. The horizontal slope decreased with increasing density of the habitat from grassland over shrub to forest, whereas that was not the case for the vertical slope. Adult survival rate increased and rate of senescence (longevity adjusted for survival rate, body mass and sampling effort) decreased with increasing vertical, but not with horizontal slope, consistent with the prediction that vertical escape indeed provides a means of reducing the impact of predation. © 2010 The Author. Journal Compilation © 2010 European Society For Evolutionary Biology.

Wensink H.H.,Heinrich Heine University Dusseldorf | Wensink H.H.,University Paris - Sud | Lowen H.,Heinrich Heine University Dusseldorf
Journal of Physics Condensed Matter | Year: 2012

Dense suspensions of self-propelled rod-like particles exhibit a fascinating variety of non-equilibrium phenomena. By means of computer simulations of a minimal model for rigid self-propelled colloidal rods with variable shape we explore the generic diagram of emerging states over a large range of rod densities and aspect ratios. The dynamics is studied using a simple numerical scheme for the overdamped noiseless frictional dynamics of a many-body system in which steric forces are dominant over hydrodynamic ones. The different emergent states are identified by various characteristic correlation functions and suitable order parameter fields. At low density and aspect ratio, a disordered phase with no coherent motion precedes a highly cooperative swarming state with giant number fluctuations at large aspect ratio. Conversely, at high densities weakly anisometric particles show a distinct jamming transition whereas slender particles form dynamic laning patterns. In between there is a large window corresponding to strongly vortical, turbulent flow. The different dynamical states should be verifiable in systems of swimming bacteria and artificial rod-like micro-swimmers. © 2012 IOP Publishing Ltd.

Szavits-Nossan J.,University of Edinburgh | Evans M.R.,University of Edinburgh | Majumdar S.N.,University Paris - Sud
Physical Review Letters | Year: 2014

Condensation is the phenomenon whereby one of a sum of random variables contributes a finite fraction to the sum. It is manifested as an aggregation phenomenon in diverse physical systems such as coalescence in granular media, jamming in traffic, and gelation in networks. We show here that the same condensation scenario, which normally happens only if the underlying probability distribution has tails heavier than exponential, can occur for light-tailed distributions in the presence of additional constraints. We demonstrate this phenomenon on the sample variance, whose probability distribution conditioned on the particular value of the sample mean undergoes a phase transition. The transition is manifested by a change in behavior of the large deviation rate function. © 2014 American Physical Society.

Bianchi P.,Telecom ParisTech | Debbah M.,Supelec | Maida M.,University Paris - Sud | Najim J.,Telecom ParisTech
IEEE Transactions on Information Theory | Year: 2011

This paper introduces a unified framework for the detection of a single source with a sensor array in the context where the noise variance and the channel between the source and the sensors are unknown at the receiver. The Generalized Maximum Likelihood Test is studied and yields the analysis of the ratio between the maximum eigenvalue of the sampled covariance matrix and its normalized trace. Using recent results from random matrix theory, a practical way to evaluate the threshold and the p-value of the test is provided in the asymptotic regime where the number K of sensors and the number N of observations per sensor are large but have the same order of magnitude. The theoretical performance of the test is then analyzed in terms of Receiver Operating Characteristic (ROC) curve. It is, in particular, proved that both Type I and Type II error probabilities converge to zero exponentially as the dimensions increase at the same rate, and closed-form expressions are provided for the error exponents. These theoretical results rely on a precise description of the large deviations of the largest eigenvalue of spiked random matrix models, and establish that the presented test asymptotically outperforms the popular test based on the condition number of the sampled covariance matrix. © 2011 IEEE.

Yu C.-H.,Leiden University | Yu C.-H.,University of Texas Southwestern Medical Center | Teulade-Fichou M.-P.,Leiden University | Olsthoorn R.C.L.,Leiden University | Olsthoorn R.C.L.,University Paris - Sud
Nucleic Acids Research | Year: 2014

Guanine-rich sequences can fold into four-stranded structures of stacked guanine-tetrads, so-called G-quadruplexes (G4). These unique motifs have been extensively studied on the DNA level; however, exploration of the biological roles of G4s at the RNA level is just emerging. Here we show that G4 RNA when introduced within coding regions are capable of stimulating -1 ribosomal frameshifting (-1 FS) in vitro and in cultured cells. Systematic manipulation of the loop length between each G-tract revealed that the -1 FS efficiency positively correlates with G4 stability. Addition of a G4-stabilizing ligand, PhenDC3, resulted in higher -1 FS. Further, we demonstrated that the G4s can stimulate +1 FS and stop codon readthrough as well. These results suggest a potentially novel translational gene regulation mechanism mediated by G4 RNA. © 2013 The Author(s) 2013. Published by Oxford University Press.

Zitvogel L.,French Institute of Health and Medical Research | Zitvogel L.,Institute Gustave Roussy | Zitvogel L.,University Paris - Sud | Galluzzi L.,University of Paris Descartes | And 5 more authors.
Immunity | Year: 2013

Conventional chemotherapeutics and targeted antineoplastic agents have been developed based on the simplistic notion that cancer constitutes a cell-autonomous genetic or epigenetic disease. However, it is becoming clear that many of the available anticancer drugs that have collectively saved millions of life-years mediate therapeutic effects by eliciting de novo or reactivating pre-existing tumor-specific immune responses. Here, we discuss the capacity of both conventional and targeted anticancer therapies to enhance the immunogenic properties of malignant cells and to stimulate immune effector cells, either directly or by subverting the immunosuppressive circuitries that preclude antitumor immune responses in cancer patients. Accumulating evidence indicates that the therapeutic efficacy of several antineoplastic agents relies on their capacity to influence the tumor-host interaction, tipping the balance toward the activation of an immune response specific for malignant cells. We surmise that the development of successful anticancer therapies will be improved and accelerated by the immunological characterization of candidate agents. © 2013 Elsevier Inc.

Jerome D.,University Paris - Sud
Journal of Superconductivity and Novel Magnetism | Year: 2012

This survey provides a brief account for the start of organic superconductivity motivated by the quest for high T c superconductors and its development since the 1980s. Besides superconductivity found in 1D organics in 1980, progresses in this field of research have contributed to better understand the physics of low-dimensional conductors highlighted by the wealth of new remarkable properties. Correlations conspire to govern the low-temperature properties of the metallic phase. The contribution of antiferromagnetic fluctuations to the interchain cooper pairing proposed by the theory is borne out by experimental investigations and supports superconductivity emerging from a non-Fermi-liquid background. Quasi-one-dimensional organic superconductors can therefore be considered as simple prototype systems for the more complex high T c materials. © Springer Science+Business Media, LLC 2012.

Aubin H.-J.,University Paris - Sud | Daeppen J.-B.,University of Lausanne
Drug and Alcohol Dependence | Year: 2013

Background: European Medicines Agency guidelines recognize two different treatment goals for alcohol dependence: abstinence and reduction in alcohol consumption. All currently approved agents are indicated for abstinence. This systematic review aimed to identify drugs in development for alcohol dependence treatment and to establish, based upon trial design, if any are seeking market authorization for reduction in consumption. Methods: We searched PubMed and Embase (December 2001-November 2011) to identify agents in development for alcohol dependence treatment. Additional studies were identified by searching ClinicalTrials.gov and the R&D Insight and Clinical Trials Insight databases. Studies in which the primary focus was treatment of comorbidity, or n≤. 20, were excluded. Studies were then classified as 'abstinence' if they: described a detoxification/alcohol withdrawal period; enrolled patients who had undergone detoxification previously; or presented relapse/abstinence rates as the primary outcome. Studies in patients actively drinking at baseline were classified as 'reduction in consumption'. Results: Of 602 abstracts identified, 45 full-text articles were eligible. Five monotherapies were in development for alcohol dependence treatment: topiramate, fluvoxamine, aripiprazole, flupenthixol and nalmefene. Nalmefene was the only agent whose sponsor was clearly seeking definitive approval for reduction in consumption. Development status was unclear for topiramate, fluvoxamine, aripiprazole and flupenthixol. Fifteen agents were examined in published exploratory investigator-initiated trials; the majority focused on abstinence. Ongoing (unpublished) trials tended to focus on reduction in consumption. Conclusions: While published studies generally focused on abstinence, ongoing trials focused on reduction in consumption, suggesting a change in emphasis in the approach to treating alcohol dependence. © 2013 Elsevier Ireland Ltd.

Decelle A.,University Paris - Sud | Krzakala F.,CNRS Gulliver Laboratory | Moore C.,Santa Fe Institute | Zdeborova L.,CEA Saclay Nuclear Research Center
Physical Review Letters | Year: 2011

We present an asymptotically exact analysis of the problem of detecting communities in sparse random networks generated by stochastic block models. Using the cavity method of statistical physics and its relationship to belief propagation, we unveil a phase transition from a regime where we can infer the correct group assignments of the nodes to one where these groups are undetectable. Our approach yields an optimal inference algorithm for detecting modules, including both assortative and disassortative functional modules, assessing their significance, and learning the parameters of the underlying block model. Our algorithm is scalable and applicable to real-world networks, as long as they are well described by the block model. © 2011 American Physical Society.

Descotes-Genon S.,University Paris - Sud | Matias J.,Autonomous University of Barcelona | Virto J.,Autonomous University of Barcelona
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

We present a global analysis of the B→K*(→Kπ) μ+μ- decay using the recent LHCb measurements of the primary observables P1,2 and P4,5,6,8′. Some of them exhibit large deviations with respect to the Standard Model (SM) predictions. We explain the observed pattern of deviations through a large new physics contribution to the Wilson coefficient of the semileptonic operator O9. This contribution has an opposite sign to the SM one, i.e., reduces the size of this coefficient significantly. A good description of data is achieved by allowing for new physics contributions to the Wilson coefficients C7 and C9 only. We find a 4.5σ deviation with respect to the SM prediction, combining the large-recoil B→K*(→Kπ) μ+μ- observables with other radiative processes. Once low-recoil observables are included the significance gets reduced to 3.9σ. We have tested different sources of systematics, none of them modifying our conclusions significantly. Finally, we propose additional ways of measuring the primary observables through new foldings. © 2013 American Physical Society.

Drummond J.M.,Physique Theorique Lapth11Umr 5108 Associee niversite Of Savoie | Henn J.,Physique Theorique Lapth11Umr 5108 Associee niversite Of Savoie | Korchemsky G.P.,University Paris - Sud | Sokatchev E.,Physique Theorique Lapth11Umr 5108 Associee niversite Of Savoie
Nuclear Physics B | Year: 2010

Planar gluon amplitudes in N = 4 SYM are remarkably similar to expectation values of Wilson loops made of light-like segments. We argue that the latter can be determined by making use of the conformal symmetry of the gauge theory, broken by cusp anomalies. We derive the corresponding anomalous conformal Ward identities valid to all loops and show that they uniquely fix the form of the finite part of a Wilson loop with n cusps (up to an additive constant) for n = 4 and 5 and reduce the freedom in it to a function of conformal invariants for n ≥ 6. We also present an explicit two-loop calculation for n = 5. The result confirms the form predicted by the Ward identities and matches the finite part of the two-loop five-gluon planar MHV amplitude, up to a constant. This constitutes another non-trivial test of the Wilson loop/gluon amplitude duality. © 2009 Elsevier B.V. All rights reserved.

Moniez M.,University Paris - Sud
General Relativity and Gravitation | Year: 2010

Microlensing is now a very popular observational astronomical technique. The investigations accessible through this effect range from the dark matter problem to the search for extra-solar planets. In this review, the techniques to search for microlensing effects and to determine optical depths through the monitoring of large samples of stars will be described. The consequences of the published results on the knowledge of the Milky-Way structure and its dark matter component will be discussed. The difficulties and limitations of the ongoing programs and the perspectives of the microlensing optical depth technique as a probe of the Galaxy structure will also be detailed. © 2010 Springer Science+Business Media, LLC.

Falkowski A.,University Paris - Sud | Riva F.,Ecole Polytechnique Federale de Lausanne
Journal of High Energy Physics | Year: 2015

Abstract: We discuss electroweak precision constraints on dimension-6 operators in the effective theory beyond the standard model. We identify the combinations of these operators that are constrained by the pole observables (the W and Z masses and on-shell decays) and by the W boson pair production. To this end, we define a set of effective couplings of W and Z bosons to fermions and to itself, which capture the effects of new physics corrections. This formalism clarifies which operators are constrained by which observable, independently of the adopted basis of operators. We obtain numerical constraints on the coefficients of dimension-6 operator in a form that can be easily adapted to any particular basis of operators, or any particular model with new heavy particles. © 2015, The Author(s).

Hadjidakis C.,University Paris - Sud
Nuclear Physics A | Year: 2014

In heavy-ion collisions at the LHC, the ALICE Collaboration is studying Quantum Chromodynamics (QCD) matter at very high energy density where the formation of a Quark Gluon Plasma (QGP) is expected. Quarkonium production is an important probe to characterize the QGP properties. High precision data in pp collisions provide the baseline of the Pb-Pb measurements and data in p-Pb collisions serve to quantify the contribution of initial and/or final state effects, related to cold nuclear matter. Since 2010, the LHC provided Pb-Pb collisions at √sNN=2.76TeV, pp collisions at various energies and in 2013 p-Pb collisions at √sNN=5.02TeV. ALICE measures quarkonium production from zero transverse momentum in the dimuon channel at forward rapidity and in the dielectron channel at mid-rapidity. This proceedings presents the new results on inclusive production of J/ψ, ψ(2S) and Y{hooktop} performed in p-Pb collisions and on the pT dependence of inclusive J/ψ in Pb-Pb collisions. The contribution of J/ψ from B hadrons to the inclusive production in Pb-Pb is also discussed. Finally, the p-Pb measurements allow an estimation of the contribution of the cold nuclear matter effect to the Pb-Pb measurements and this is also reported. © 2014 CERN.

Parentani R.,University Paris - Sud | Serreau J.,CNRS Astroparticle and Cosmology Lab
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

We propose a new approach to compute correlators of quantum fields in de Sitter space. It is based on nonequilibrium field theory techniques, and exploits de Sitter symmetries so as to partially reduce the number of independent variables of n-point functions in a manner that preserves the usefulness of a momentum representation, e.g., for writing spatial convolution integrals as simple products. In this representation, the two-point function of a scalar field only depends on two physical momenta, and the corresponding Schwinger-Dyson evolution equations take the form of momentum flow equations. Moreover, standard diagrammatic rules can be entirely formulated in this representation. The method is suitable for analytical approximations as well as numerical implementations. In forthcoming publications, we apply it to resum infrared logarithmic terms appearing in the perturbative calculation of vertex and correlation functions. © 2013 American Physical Society.

Babichev E.,University Paris - Sud | Babichev E.,University Pierre and Marie Curie | Esposito-Farese G.,University Pierre and Marie Curie
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

We study spherically symmetric solutions of the cubic covariant Galileon model in curved spacetime in the presence of a matter source, in the test scalar field approximation. We show that a cosmological time evolution of the Galileon field gives rise to an induced matter-scalar coupling, due to the Galileon-graviton kinetic braiding, therefore the solution for the Galileon field is nontrivial even if the bare matter-scalar coupling constant is set to zero. The local solution crucially depends on the asymptotic boundary conditions, and in particular, Minkowski and de Sitter asymptotics correspond to different branches of the solution. We study the stability of these solutions, namely, the well posedness of the Cauchy problem and the positivity of energy for scalar and tensor perturbations, by diagonalizing the kinetic terms of the spin-2 and spin-0 degrees of freedom. In addition, we find that in the presence of a cosmological time evolution of the Galileon field, its kinetic mixing with the graviton leads to a friction force resulting in efficient damping of scalar perturbations within matter. © 2013 American Physical Society.

Vainchenker W.,French Institute of Health and Medical Research | Vainchenker W.,Institute Gustave Roussy | Vainchenker W.,University Paris - Sud | Constantinescu S.N.,Ludwig Institute for Cancer Research
Oncogene | Year: 2013

The Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway is central to signaling by cytokine receptors, a superfamily of more than 30 transmembrane proteins that recognize specific cytokines, and is critical in blood formation and immune response. Many of those receptors transmit anti-apoptotic, proliferative and differentiation signals, and their expression and functions are critical for the formation of blood lineages. Several cancers, including blood malignancies, have been associated with constitutive activation of members of the STAT family, which normally require JAK-mediated tyrosine phosphorylation for transcriptional activation. More recently, human myeloproliferative neoplasms were discovered to be associated with a unique acquired somatic mutation in JAK2 (JAK2 V617F), rare exon 12 JAK2 mutations, or thrombopoietin receptor mutations that constitutively activate wild-type JAK2. Prompted by these observations, many studies have explored the possibility that JAKs, cytokine receptors, or other components of the JAK/STAT pathway are mutated or upregulated in several hematological malignancies. This has been observed in certain pediatric acute lymphoblastic leukemias and adult T-cell lymphoblastic leukemias, and overexpression of JAK2 seems to be important in Hodgkin lymphoma. Here we discuss the nature and respective contribution of mutations dysregulating the JAK/STAT pathway in hematological malignancies and present examples in which such mutations drive the disease, contribute to the phenotype, or provide a survival and proliferative advantage. JAK inhibitors are making their way into the therapeutic arsenal (for example, in myelofibrosis), and we discuss the possibility that other hematological diseases might benefit from treatment with these inhibitors in combination with other agents. © 2013 Macmillan Publishers Limited. All rights reserved 0950-9232/13.

Klein C.,University of Burgundy | Saut J.-C.,University Paris - Sud
Physica D: Nonlinear Phenomena | Year: 2015

We provide a detailed numerical study of various issues pertaining to the dynamics of the Burgers' equation perturbed by a weak dispersive term: blow-up in finite time versus global existence, nature of the blow-up, existence for "long" times, and the decomposition of the initial data into solitary waves plus radiation. We numerically construct solitary waves for fractional Korteweg-de Vries equations. © 2014 Elsevier B.V. All rights reserved.

Piram M.,University Paris - Sud | Mahr A.,University Paris Diderot
Current Opinion in Rheumatology | Year: 2013

PURPOSE OF REVIEW: To review the current knowledge of epidemiological features of immunoglobulin (Ig) A vasculitis (Henoch-Schönlein) and disease etiology. RECENT FINDINGS: The annual incidence of IgA vasculitis in the population is an estimated 3-26.7/100 000 for children and infants and 0.8-1.8/100 000 for adults. These may be conservative approximations of the true frequency because of skewed case-finding strategies. In children, the marked autumn-winter peak in incidence rates, the frequent occurrence after an upper respiratory tract infection and the short interval between disease onset in index cases and in other family members collectively point to a transmissible infectious process. A subset of adult IgA vasculitis could be related to preceding or concurrent malignancies. Despite several lines of evidence supporting the critical role of an exogenous factor in IgA vasculitis, recent progress has been made in understanding the genetic susceptibility to IgA vasculitis. Recent findings also lessened the suggestion that IgA vasculitis might be triggered by vaccination. SUMMARY: IgA vasculitis is two to 33 times more common in children than adults and appears to have a strong environmental component, with possibly different risk factors in childhood and adulthood. Support is strengthening for a role of genetics in IgA vasculitis. © 2013 Wolters Kluwer Health | Lippincott Williams &Wilkins.

Guidal M.,University Paris - Sud
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2010

We have analyzed the longitudinally polarized proton target asymmetry data of the Deep Virtual Compton process recently published by the HERMES Collaboration in terms of Generalized Parton Distributions. We have fitted these new data in a largely model-independent fashion and the procedure results in numerical constraints on the H̃Im Compton Form Factor. We present its t- and ξ-dependencies. We also find improvement on the determination of two other Compton Form Factors, HRe and HIm. © 2010 Elsevier B.V.

Mambrini Y.,University Paris - Sud
Journal of Cosmology and Astroparticle Physics | Year: 2010

Several string or GUT constructions motivate the existence of a dark U(1)D gauge boson which interacts with the Standard Model only through its kinetic mixing. We compute the dark matter abundance in such scenario and the constraints in the light of the recent data from CoGENT, CDMSII and XENON100. We show in particular that a region with relatively light WIMPS, MzD ≲ 40 GeV and a kinetic mixing 10-4 ≲ δ ≲ 10 -3 is not yet excluded by the last experimental data and seems to give promising signals in a near future. We also compute the value of the kinetic mixing needed to explain the DAMA/CoGENT/CRESST excesses and find that for MzD ≲ 30 GeV, δ ∼ 10-3 is sufficient to fit with the data. © 2010 IOP Publishing Ltd and SISSA.

Davier M.,University Paris - Sud
Nuclear and Particle Physics Proceedings | Year: 2015

The BaBar collaboration has nearly completed a program of precise measurements of the cross sections for the dominant channels of e+e-→hadrons from threshold to 3 GeV using the initial-state radiation (ISR) method, i.e. the measurement of the cross sections e+e-→γhadrons with the energetic γ detected at large angle to the beams. These data are used as input to vacuum polarization dispersion integrals, in particular the hadronic contribution to the muon g-2 anomaly. In addition to the recently measured π+π- and K+K- cross sections, giving the dominant contribution, multihadronic channels have been investigated, with some recent examples presented here for the π+π-π+π-, K+K-ππ, KSKL, KSKLπ+π-, KSKSπ+π- channels. The BaBar results have the best precision and cover for the first time almost all significant hadronic contributions below 2 GeV entering the muon g-2 prediction. © 2015 Elsevier B.V.

Petrov D.S.,University Paris - Sud
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2014

We show that by coupling two hyperfine states of an atom in an optical lattice one can independently control two-, three-, and four-body on-site interactions in a nonperturbative manner. In particular, under typical conditions of current experiments, one can have a purely three- or four-body interacting gas of K39 atoms characterized by on-site interaction shifts of several 100 Hz. © 2014 American Physical Society.

Dudas E.,Ecole Polytechnique - Palaiseau | Heurtier L.,Ecole Polytechnique - Palaiseau | Mambrini Y.,University Paris - Sud
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2014

We propose different scenarios where a keV dark matter annihilates to produce a monochromatic signal. The process is generated through the exchange of a light scalar of mass of order 300 keV-50 MeV coupling to photon through loops or higher-dimensional operators. For natural values of the couplings and scales, the model can generate a gamma-ray line which can fit with the recently identified 3.5 keV x-ray line. © 2014 American Physical Society.

Studying p-Pb collisions at LHC energies allows a quantitative evaluation of the cold nuclear matter (CNM) effects. Event activity dependence of the J/ψ production is under intense studies both theoretically and experimentally [1-5] and is expected to provide important insights on the influence of CNM. This paper presents the first results on event activity dependence of the inclusive J/ψ production at backward (-4.46