Orsay, France
Orsay, France

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.

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French National Center for Scientific Research and University Paris - Sud | Date: 2015-04-09

The invention relates to compounds which are inhibitors of the polymerization of tubulin, to the methods for the production thereof, and to the uses of same.

Laboratoire Francais Du Fractionnement Et Des Biotechnologies, French National Center for Scientific Research and University Paris - Sud | Date: 2015-05-28

Disclosed is a copolymer of following formula (I): in which:x is an integer between 10 and 250, preferably between 40 and 120, y is an integer between 4 and 100, preferably between 10 and 100, preferably between 19 and 60, z is an integer between 0 and (100y), preferably equal to 0, R represents an alkyl radical having 1 to 10 carbon atoms, a phospholipid, a glycosaminoglycan or an affinity ligand, and R represents a hydrogen, the CH_(2)CCH group, a CH_(2)-1H-1,2,3-triazole group, a CH_(2)CH_(2)CH_(2)SR group, in which R represents an alkyl radical having 1 to 10 carbon atoms, a phospholipid, a glycosaminoglycan, an affinity ligand or an imaging probe, and the uses of same.

University Paris - Sud, French Atomic Energy Commission and French National Center for Scientific Research | Date: 2015-04-03

Complexes including a solid support and a material with a matrix structure containing domains complexing rare earth or strategic metals, preparation process thereof and use thereof for extracting or separating the rare earth or strategic metals in an aqueous or organic medium.

University Paris - Sud and Lille University Hospital Center | Date: 2015-04-16

The invention relates to an isolated monoclonal antibody that specifically binds to the D4 domain of VWF, competes for binding to VWF D4 domain with ADAMTS13 and partially inhibits ADAMTS 13 -mediated degradation of VWF. More particularly, the invention relates to an isolated monoclonal antibody comprising a heavy chain wherein the variable domain comprises at least one CDR having a sequence selected from the group consisting of SEQ ID NO: 3 for H-CDR1, SEQ ID NO: 4 for H-CDR2 and SEQ ID NO: 5 for H-CDR3 and a light chain wherein the variable domain comprises at least one CDR having a sequence selected from the group consisting of SEQ ID NO: 7 for L-CDR1, SEQ ID NO: 8 for L-CDR2 and SEQ ID NO: 9 for L-CDR3. Antibodies of the invention are presented to be useful in for the prevention or the treatment of bleeding episodes, such as bleeding episodes occurring in patients with aortic stenosis or patients with ventricular assist devices (VAD).

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.

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.

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 | And 2 more authors.
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2013

We analyze the extent to which the LHC and Tevatron results as of the end of 2012 constrain invisible (or undetected) decays of the Higgs boson-like state at ~125 GeV. To this end we perform global fits for several cases: (1) a Higgs boson with Standard Model (SM) couplings but additional invisible decay modes; (2) SM couplings to fermions and vector bosons, but allowing for additional new particles modifying the effective Higgs couplings to gluons and photons; (3) no new particles in the loops but tree-level Higgs couplings to the up-quarks, down-quarks and vector bosons, relative to the SM, treated as free parameters. We find that in the three cases invisible decay rates of 23%, 61%, 88%, respectively, are consistent with current data at 95% confidence level (CL). Limiting the coupling to vector bosons, CV, to CV≤1 in case (3) reduces the allowed invisible branching ratio to 56% at 95% CL. Requiring in addition that the Higgs couplings to quarks have the same sign as in the SM, an invisible rate of up to 36% is allowed at 95% CL. We also discuss direct probes of invisible Higgs decays, as well as the interplay with dark matter searches. © 2013 .

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.

Tichit P.-H.,University Paris - Sud | Burokur S.N.,University Paris - Sud | Qiu C.-W.,National University of Singapore | De Lustrac A.,University Paris - Sud
Physical Review Letters | Year: 2013

It has long been conjectured that isotropic radiation by a simple coherent source is impossible due to changes in polarization. Though hypothetical, the isotropic source is usually taken as the reference for determining a radiator's gain and directivity. Here, we demonstrate both theoretically and experimentally that an isotropic radiator can be made of a simple and finite source surrounded by electric-field-driven LC resonator metamaterials designed by space manipulation. As a proof-of-concept demonstration, we show the first isotropic source with omnidirectional radiation from a dipole source (applicable to all distributed sources), which can open up several possibilities in axion electrodynamics, optical illusion, novel transformation-optic devices, wireless communication, and antenna engineering. Owing to the electric- field-driven LC resonator realization scheme, this principle can be readily applied to higher frequency regimes where magnetism is usually not present. © 2013 American Physical Society.

Becirevic D.,University Paris - Sud | Kosnik N.,University Paris - Sud | Kosnik N.,Jozef Stefan Institute | Tayduganov A.,University Paris - Sud
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2012

Recent experimental results for the ratio of the branching fractions of B-→D(*)τν-τ and B-→D(*)μν-μ decays came as a surprise and lead to a discussion of possibility to constraining New Physics through these modes. Here we focus on B(B-→Dτν-τ)/B(B-→Dμν-μ) and argue that the result is consistent with the Standard Model within 2. σ, and that the test of compatibility of this ratio with the Standard Model can be done experimentally with a minimal theory input. We also show that these two decay channels can provide us with quite good constraints of the New Physics couplings. © 2012 Elsevier B.V.

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.

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.

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.

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.

Becirevic D.,University Paris - Sud | Fajfer S.,University Paris - Sud | Kosnik N.,University of Ljubljana | Kosnik N.,Jozef Stefan Institute
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

We explore a scenario of new physics entering the description of B→K(∗)μμ decay through couplings to the operators O9,10′, satisfying C9′=-C10′. From the current data on B(Bs→μμ) and B(B→Kμμ)[15,22]GeV2, we obtain constraints on ReC10′ and ImC10′ which we then assume to be lepton specific, and find RK=B(B→Kμμ)/B(B→Kμμ)[1,6]GeV2=0.88(8), consistent with the recent value measured at the LHCb. A specific realization of this scenario is the one with a scalar leptoquark state Δ, in which C10′ is related to the mass of Δ and its Yukawa couplings. We then show that this scenario does not make any significant impact on Bs-B¯s mixing amplitude or on B(B→Kνν¯). Instead, it can modify RK∗=B(B→K∗μμ)/B(B→K∗μμ)[1,6]GeV2, which will soon be experimentally measured, and we find it to be RK∗=1.11(8), while RK∗/RK=1.27(19). A similar ratio of forward-backward asymmetries also becomes lower than in the Standard Model. © 2015 American Physical Society.

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.

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.

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.

Prados A.,University of Seville | Prados A.,University Paris - Sud | Trizac E.,University Paris - Sud
Physical Review Letters | Year: 2014

While memory effects have been reported for dense enough disordered systems such as glasses, we show here by a combination of analytical and simulation techniques that they are also intrinsic to the dynamics of dilute granular gases. By means of a certain driving protocol, we prepare the gas in a state where the granular temperature T coincides with its long time limit. However, T does not subsequently remain constant but exhibits a nonmonotonic evolution before reaching its nonequilibrium steady value. The corresponding so-called Kovacs hump displays a normal behavior for weak dissipation (as observed in molecular systems) but is reversed under strong dissipation, where it, thus, becomes anomalous. © 2014 American Physical Society.

Kroemer G.,U848 | Kroemer G.,University of Paris Descartes | Kroemer G.,University Paris - Sud | Galluzzi L.,Institute Gustave Roussy | And 7 more authors.
Annual Review of Immunology | Year: 2013

Depending on the initiating stimulus, cancer cell death can be immunogenic or nonimmunogenic. Immunogenic cell death (ICD) involves changes in the composition of the cell surface as well as the release of soluble mediators, occurring in a defined temporal sequence. Such signals operate on a series of receptors expressed by dendritic cells to stimulate the presentation of tumor antigens to T cells. We postulate that ICD constitutes a prominent pathway for the activation of the immune system against cancer, which in turn determines the long-term success of anticancer therapies. Hence, suboptimal regimens (failing to induce ICD), selective alterations in cancer cells (preventing the emission of immunogenic signals during ICD), or defects in immune effectors (abolishing the perception of ICD by the immune system) can all contribute to therapeutic failure. We surmise that ICD and its subversion by pathogens also play major roles in antiviral immune responses. © Copyright 2013 by Annual Reviews. All rights reserved.

Shen H.-M.,National University of Singapore | Codogno P.,University Paris - Sud
Autophagy | Year: 2011

The concept of autophagic cell death was first established based on observations of increased autophagic markers in dying cells. The major limitation of such a morphology-based definition of autophagic cell death is that it fails to establish the functional role of autophagy in the cell death process, and thus contributes to the confusion in the literature regarding the role of autophagy in cell death and cell survival. Here we propose to define autophagic cell death as a modality of non-apoptotic or necrotic programmed cell death in which autophagy serves as a cell death mechanism, upon meeting the following set of criteria: (i) cell death occurs without the involvement of apoptosis; (ii) there is an increase of autophagic flux, and not just an increase of the autophagic markers, in the dying cells; and (iii) suppression of autophagy via both pharmacological inhibitors and genetic approaches is able to rescue or prevent cell death. In light of this new definition, we will discuss some of the common problems and difficulties in the study of autophagic cell death and also revisit some wellreported cases of autophagic cell death, aiming to achieve a better understanding of whether autophagy is a real killer, an accomplice or just an innocent bystander in the course of cell death. At present, the physiological relevance of autophagic cell death is mainly observed in lower eukaryotes and invertebrates such as Dictyostelium discoideum and Drosophila melanogaster. We believe that such a clear definition of autophagic cell death will help us study and understand the physiological or pathological relevance of autophagic cell death in mammals. © 2011 Landes Bioscience.

Kosnik N.,University Paris - Sud | Kosnik N.,Jozef Stefan Institute
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

We list all scalar and vector leptoquark states that contribute to the b→s +- effective Hamiltonian. There are altogether three scalar and four vector leptoquarks that are relevant. For contribution of each state we infer the correlations between effective operators and find that only two baryon number-violating vector leptoquarks give rise to scalar and pseudoscalar four-fermion operators, whereas the scalar states can contribute to those operators only when two states with same charge are present. We bound the resulting Wilson coefficients by imposing experimental constraints coming from branching fractions of B→K +-, B s→μ +μ -, and B→X sμ +μ - decays. © 2012 American Physical Society.

Vandenabeele P.,Ghent University | Galluzzi L.,French Institute of Health and Medical Research | Galluzzi L.,University Paris - Sud | Vanden Berghe T.,Ghent University | And 3 more authors.
Nature Reviews Molecular Cell Biology | Year: 2010

For a long time, apoptosis was considered the sole form of programmed cell death during development, homeostasis and disease, whereas necrosis was regarded as an unregulated and uncontrollable process. Evidence now reveals that necrosis can also occur in a regulated manner. The initiation of programmed necrosis, 'necroptosis', by death receptors (such as tumour necrosis factor receptor 1) requires the kinase activity of receptor-interacting protein 1 (RIP1; also known as RIPK1) and RIP3 (also known as RIPK3), and its execution involves the active disintegration of mitochondrial, lysosomal and plasma membranes. Necroptosis participates in the pathogenesis of diseases, including ischaemic injury, neurodegeneration and viral infection, thereby representing an attractive target for the avoidance of unwarranted cell death. © 2010 Macmillan Publishers Limited. All rights reserved.

Ben-Abdallah P.,University Paris - Sud | Biehs S.-A.,University Paris - Sud | Biehs S.-A.,Carl von Ossietzky University | Joulain K.,CNRS Pprime Institute
Physical Review Letters | Year: 2011

In this Letter, an N-body theory for the radiative heat exchange in thermally nonequilibrated discrete systems of finite size objects is presented. We report strong exaltation effects of heat flux which can be explained only by taking into account the presence of many-body interactions. Our theory extends the standard Polder and van Hove stochastic formalism used to evaluate heat exchanges between two objects isolated from their environment to a collection of objects in mutual interaction. It gives a natural theoretical framework to investigate the photon heat transport properties of complex systems at the mesoscopic scale. © 2011 American Physical Society.

Boulle O.,CEA Grenoble | Malinowski G.,University Paris - Sud | Klaui M.,Ecole Polytechnique Federale de Lausanne | Klaui M.,Paul Scherrer Institute
Materials Science and Engineering R: Reports | Year: 2011

The manipulation of a magnetic domain wall (DW) by a spin polarized current in ferromagnetic nanowires has attracted tremendous interest during the last years due to fundamental questions in the fields of spin dependent transport phenomena and magnetization dynamics but also due to promising applications, such as DW based magnetic memory concepts and logic devices. We comprehensively review recent developments in the field of geometrically confined domain walls and in particular current induced DW dynamics. We focus on the influence of the magnetic and electronic transport properties of the materials on the spin transfer effect in DWs. After considering the different DW structures in ferromagnetic nanowires, the theory of magnetization dynamics induced by a spin polarized current is presented. We first discuss the different current induced torques and their origin in the light of recent theories based on a simple s-d exchange model and beyond. This leads to a modified Landau-Lifshitz-Gilbert equation of motion where the different spin transfer torques are included and we discuss their influence on the DW dynamics on the basis of simple 1D models and recent micromagnetic simulations studies. Experimental results illustrating the effects of spin transfer in different ferromagnetic materials and geometries constitute the body of the review. The case of soft in-plane magnetized nanowires is described first, as it is the most widely studied class of ferromagnetic materials in this field. By direct imaging we show how confined domain walls in nanowires can be displaced using currents in in-plane soft magnetic materials and that using short pulses, fast velocities can be attained. While a spin polarized current can trigger DW depinning or displacement, it can also lead to a modification of the DW structure, which is described in detail as it allows one to deduce information about the underlying spin torque terms. High perpendicular anisotropy materials characterized by narrow domain walls have also raised considerable interest. These materials with only a few nanometer wide DWs combined several key advantages over soft magnetic materials such as higher non-adiabatic effects leading to lower critical current densities and high domain wall velocities. We review recent experimental results obtained in this class of materials and discuss the important implications they entail for the nature of the spin torque effect acting on DWs. © 2011 Elsevier B.V. All rights reserved.

Lu X.,Huazhong University of Science and Technology | Laroussi M.,Old Dominion University | Puech V.,University Paris - Sud
Plasma Sources Science and Technology | Year: 2012

Atmospheric-pressure non-equilibrium plasma jets (APNP-Js), which generate plasma in open space rather than in a confined discharge gap, have recently been a topic of great interest. In this paper, the development of APNP-Js will be reviewed. Firstly, the APNP-Js are grouped based on the type of gas used to ignite them and their characteristics are discussed in detail. Secondly, one of the most interesting phenomena of APNP-Js, the plasma bullet, is discussed and its behavior described. Thirdly, the very recent developments on the behavior of plasma jets when launched in a controlled environment and pressure are also introduced. This is followed by a discussion on the interaction between plasma jets. Finally, perspectives on APNP-J research are presented. © 2012 IOP Publishing Ltd.

Georges A.,Ecole Polytechnique - Palaiseau | Georges A.,Collège de France | Georges A.,University of Geneva | De Medici L.,University Paris - Sud | And 4 more authors.
Annual Review of Condensed Matter Physics | Year: 2013

Strong electronic correlations are often associated with the proximity of a Mott-insulating state. In recent years however, it has become increasingly clear that the Hund's rule coupling (intra-atomic exchange) is responsible for strong correlations in multiorbital metallic materials that are not close to a Mott insulator. Hund's coupling has two effects: It influences the energetics of the Mott gap and strongly suppresses the coherence scale for the formation of a Fermi liquid. A global picture has emerged recently, which emphasizes the importance of the average occupancy of the shell as a control parameter. The most dramatic effects occur away from half-filling or single occupancy. We review the theoretical understanding and physical properties of these Hund's metals, together with the relevance of this concept to transition-metal oxides (TMOs) of the 3d, and especially 4d, series (such as ruthenates), as well as to the iron-based superconductors (iron pnictides and chalcogenides). © 2013 by Annual Reviews. All rights reserved.

Ortega H.G.,Glaxosmithkline | Liu M.C.,Johns Hopkins Asthma and Allergy Center | Pavord I.D.,University of Oxford | Brusselle G.G.,Ghent University | And 7 more authors.
New England Journal of Medicine | Year: 2014

Background: Some patients with severe asthma have frequent exacerbations associated with persistent eosinophilic inflammation despite continuous treatment with high-dose inhaled glucocorticoids with or without oral glucocorticoids. Methods: In this randomized, double-blind, double-dummy study, we assigned 576 patients with recurrent asthma exacerbations and evidence of eosinophilic inflammation despite high doses of inhaled glucocorticoids to one of three study groups. Patients were assigned to receive mepolizumab, a humanized monoclonal antibody against interleukin-5, which was administered as either a 75-mg intravenous dose or a 100-mg subcutaneous dose, or placebo every 4 weeks for 32 weeks. The primary outcome was the rate of exacerbations. Other outcomes included the forced expiratory volume in 1 second (FEV1) and scores on the St. George's Respiratory Questionnaire (SGRQ) and the 5-item Asthma Control Questionnaire (ACQ-5). Safety was also assessed. Results: The rate of exacerbations was reduced by 47% (95% confidence interval [CI], 29 to 61) among patients receiving intravenous mepolizumab and by 53% (95% CI, 37 to 65) among those receiving subcutaneous mepolizumab, as compared with those receiving placebo (P<0.001 for both comparisons). Exacerbations necessitating an emergency department visit or hospitalization were reduced by 32% in the group receiving intravenous mepolizumab and by 61% in the group receiving subcutaneous mepolizumab. At week 32, the mean increase from baseline in FEV1 was 100 ml greater in patients receiving intravenous mepolizumab than in those receiving placebo (P = 0.02) and 98 ml greater in patients receiving subcutaneous mepolizumab than in those receiving placebo (P=0.03). The improvement from baseline in the SGRQ score was 6.4 points and 7.0 points greater in the intravenous and subcutaneous mepolizumab groups, respectively, than in the placebo group (minimal clinically important change, 4 points), and the improvement in the ACQ-5 score was 0.42 points and 0.44 points greater in the two mepolizumab groups, respectively, than in the placebo group (minimal clinically important change, 0.5 points) (P<0.001 for all comparisons). The safety profile of mepolizumab was similar to that of placebo. Conclusions: Mepolizumab administered either intravenously or subcutaneously significantly reduced asthma exacerbations and was associated with improvements in markers of asthma control. Copyright © 2014 Massachusetts Medical Society.

Lannes A.,University Paris - Sud | Prieur J.-L.,University Of Toulouse Ups Omp Irap
Journal of Geodesy | Year: 2013

In global navigation satellite systems (GNSS), the problem of retrieving clock-phase biases from network data has a basic rank defect. We analyse the different ways of removing this rank defect, and define a particular strategy for obtaining these phase biases in a standard form. The minimum-constrained problem to be solved in the least-squares (LS) sense depends on some integer vector which can be fixed in an arbitrary manner. We propose to solve the problem via an undifferenced approach based on the notion of closure ambiguity. We present a theoretical justification of this closure-ambiguity approach (CAA), and the main elements for a practical implementation. The links with other methods are also established. We analyse all those methods in a unified interpretative framework, and derive functional relations between the corresponding solutions and our CAA solution. This could be interesting for many GNSS applications like real-time kinematic PPP for instance. To compare the methods providing LS estimates of clock-phase biases, we define a particular solution playing the role of reference solution. For this solution, when a phase bias is estimated for the first time, its fractional part is confined to the one-cycle width interval centred on zero; the integer-ambiguity set is modified accordingly. Our theoretical study is illustrated with some simple and generic examples; it could have applications in data processing of most GNSS networks, and particularly global networks using GPS, Glonass, Galileo, or BeiDou/Compass satellites. © 2013 European Union.

Agency: Cordis | Branch: FP7 | Program: CPCSA | Phase: ICT-2013.9.9 | Award Amount: 74.61M | Year: 2013

This Flagship aims to take graphene and related layered materials from a state of raw potential to a point where they can revolutionize multiple industries from flexible, wearable and transparent electronics, to new energy applications and novel functional composites.\nOur main scientific and technological objectives in the different tiers of the value chain are to develop material technologies for ICT and beyond, identify new device concepts enabled by graphene and other layered materials, and integrate them to systems that provide new functionalities and open new application areas.\nThese objectives are supported by operative targets to bring together a large core consortium of European academic and industrial partners and to create a highly effective technology transfer highway, allowing industry to rapidly absorb and exploit new discoveries.\nThe Flagship will be aligned with European and national priorities to guarantee its successful long term operation and maximal impact on the national industrial and research communities.\nTogether, the scientific and technological objectives and operative targets will allow us to reach our societal goals: the Flagship will contribute to sustainable development by introducing new energy efficient and environmentally friendly products based on carbon and other abundant, safe and recyclable natural resources, and boost economic growth in Europe by creating new jobs and investment opportunities.

Agency: Cordis | Branch: FP7 | Program: NOE | Phase: ICT-2007.1.1 | Award Amount: 9.17M | Year: 2008

NEWCOM\\ is the acronym of a proposed Network of Excellence in Wireless COMmunications, submitted to Call 1 of the VII Framework Programme under the Objective ICT-2007.1.1: The Network of the Future, mainly in its target direction Ubiquitous network infrastructure and architectures. The current proposal draws inspiration, shape/form, and substantive direction from its successful predecessor, the NoE NEWCOM, which was approved and funded by the EC for 36 months starting March 1st, 2004 and ending February 28, 2007. At the same time, NEWCOM\\ aspires to inject new vision, expanded roles, ever-higher degrees of research integration, and a definitive roadmap to financial security for the long-term life of this undertaking in the European research and higher-learning space. The core concept of NEWCOM\\ is that of an NoE of medium size, greatly reduced from the initial NEWCOM Consortium, formed by keeping the most committed and performing partners, exploiting the successful integration tools that NEWCOM designed and activated, and which is created for the purpose of scientifically addressing medium/long term, complex, interdisciplinary, fundamental research problems in the field of wireless networks, focused towards identifying, posing in the right modelling perspective, and at least partially characterizing the information-communication theoretical limits. Its main objectives are: Identify a selective set of scenarios, Define suitable performance measures that take into account the wireless channel nature, Perform a detailed analysis of the main theoretical results available, Evaluate information-theoretical bounds on the achievable performance, Design and analyze transmitting/receiving algorithms and protocols in order to approach those limits, Analyze implementation aspects of the above algorithms in flexible, energy-aware user terminals, Output the major findings into an integrated simulation library, Enhance the already good cooperation level among research

Agency: Cordis | Branch: FP7 | Program: CP-FP | Phase: ENV.2008. | Award Amount: 4.68M | Year: 2009

The aim of this project is to achieve an improved knowledge of the terrestrial carbon cycle in response to climate variability and extremes, to represent and apply this knowledge over Europe with predictive terrestrial carbon cycle modelling, to interpret the model predictions in terms of vulnerability of the terrestrial in particular soil carbon pools and give according advice to EU climate and soil protection policies. This objective will be achieved by integrating three major types of recent and new solid scientific carbon cycle data, from: (i) soil process studies, (ii) a network of established ecosystem manipulation experiments, and (iii) long-term observations spanning several times-scales (e.g. eddy covariance data, tree rings and growth, crop yields, long-term remote sensing data on soil moisture and vegetation activity and soil carbon inventories). The integration will be reached by establishing a consistent and harmonized data base and by confronting the terrestrial carbon cycle models with the multiple data sets within a Bayesian model identification and improvement procedure. Specific model development concerning processes affected by extreme events (e.g. soil carbon destabilization, tree growth response incl. lag effects and mortality) will be included and followed by model testing and improvement against the data made available in the project. The improved models will simulate terrestrial processes relevant to carbon balance and soil erosion at pan- European scale using regionalized climate scenarios with explicit inclusion of extreme climatic events. Since we are using several climate scenarios and an ensemble of models we will be able to characterize the uncertainties in prediction coming from models and climate scenarios. We will interpret the empirical evidence from the observational work and the model simulations in a framework of vulnerability assessment and disseminate and discuss results with stakeholders at EU level.

Agency: Cordis | Branch: FP7 | Program: NOE | Phase: ICT-2009.2.2 | Award Amount: 7.57M | Year: 2010

Linguistic diversity is a corner stone of our multicultural European society. To preserve this essential asset in the age of the emerging information and knowledge society, Europe needs ICT technologies and applications at affordable costs that\n\n enable communication, collaboration and participation across language boundaries\n secure their language users equal access to the information and knowledge society\n support each language in the advanced functionalities of networked ICT\n\nPrerequisites of these applications are advances in several fields of Human Language Technologies (HLT) such as\n\n machine translation (MT) including automatic translation and machine assisted human translation\n technologies for information and knowledge management including IR, crosslingual IR and corporate memories\n technologies for document and content production and management (including authoring tools, language checking and interactive content applications)\n technologies for intuitive interfaces to all types of technology (including multimodal user interfaces, speech interfaces for interactive mobile applications, robot control interfaces)\n\nBuilding a single EU information space reflecting and supporting the cultural diversity of our continent as an adequate foundation for the multilingual European information and knowledge society is a major challenge. Because of the complexity of human language and the number of languages to be included this challenge demands a large collective effort of research and language communities as well as several industrial sectors.\n\nT4ME shall seek progress by approaching open problems in collaboration with other research fields such as machine learning, social computing, cognitive systems, knowledge technologies and multimedia content. It shall mobilize and strengthen the European HLT community encompassing researchers, developers and language professionals through networking of research and by creating new schemes of sharing resources and efforts.

Agency: Cordis | Branch: FP7 | Program: CP | Phase: ICT-2007.8.2 | Award Amount: 2.55M | Year: 2008

ATRACO considers ambient ecologies consisting of people, context-aware artefacts and digital commodities (e.g., services and content). Members of the ecology are able to adapt to each other and form trusted ad hoc collaborations to achieve specific goals resulting from the need to serve specific human activities. The aim of this proposal is to research the factors and develop the technologies that will lead to the realisation of such ecologies (ATRACOs), following an interdisciplinary effort which involves Computer Science, HCI, AI, Control Theory and Sociology. Key factors of the ATRACO problem space that will be examined include adaptation, interoperability, context awareness, user interaction and dynamicity of trust. We will focus our efforts on seeking abstractions and mechanisms to mark the digital boundaries of ATRACOs for establishing trust relationships between its members, based on the concepts of digital territory and bubble, and to devise adaptation mechanisms based on supervisory control theory of discrete event systems and type-2 fuzzy logic. The project objectives are:.To understand the structure, principles and dynamics of the ATRACO problem space and to develop a conceptual framework consisting of a set of concepts implemented as an ontology, a novel interaction metaphor, implemented as a language and a layered architecture implemented with a set of components.. To research and implement the adaptation mechanisms and privacy policies, as part of the component platform. Adaptation will be provided in terms of artefact operation, ecology composition, network selection and man-machine interaction with respect to user context and behaviour.. To validate the results of our research by developing an integrated application testbed. We will experiment with our proposed component platform both within a testbed (iDorm-2 of UEssex) as well as within a simulation environment.

Agency: Cordis | Branch: FP7 | Program: CP | Phase: ICT-2011.3.5 | Award Amount: 15.35M | Year: 2012

Silicon with its mature integration platform has brought electronic circuits to mass-market applications - our vision is that silicon photonics will follow this revolution. Over the last years silicon photonics has seen a tremendous increase in research output, leading to commercial exploitation potential. Most of these efforts have been devoted to the development of elementary building blocks, rather than the fabrication of complete Photonic Integrated Circuits which are needed to support the large potential markets. Upgrading existing platforms to become compatible with industrialization is now essential and requires efforts on streamlining and stabilizing the design and process flows, by taking into account design robustness, process variability and integration constraints.\nEuropes silicon photonics community has demonstrated a worldwide leadership with both new scientific discoveries and excellent CMOS photonics R&D facilities.\nPLAT4Ms objective is to bring existing silicon photonics research platform to a maturity level which enables seamless transition to industry, suitable for different applications fields and manufacturing volume levels.\nProgress on three fronts is needed:\n1 Mature technologies and tools\n- Establish scalable Electrical-Optical co-design capability\n- Stabilize elementary building blocks, focus on process integration and common testing procedures\n- Develop packaging processes that support high volume manufacturing\n2 Validate each platform with application-driven test vehicles\n- Fabricate representative demonstrators in various applications fields\n3 Prepare and evaluate the next generation platform\n- Assess advanced processes with future technology nodes and scalability to high integration complexity\n\nPLAT4M gathers leading European R&D institutes and CMOS companies, key industrial and research players in design, packaging as well as end-users in different application fields in order to build the whole supply chain.

Agency: Cordis | Branch: FP7 | Program: MC-ITN | Phase: FP7-PEOPLE-ITN-2008 | Award Amount: 2.58M | Year: 2009

Thermal management in innovative technology is a major problem to be solved, especially in novel electronic devices, such as further miniaturized microchips, hard disks and interfaces between biological structures (e.g. nerve cells) and semiconductor microstructures. In this Initial Training Network (ITN) we will train young researchers through an experimental/technological and theoretical approach to the application of a new highly efficient magnetic mode of thermal conduction for thermal management. This magnetic heat transport was discovered by members of this consortium and occurs in novel quasi-one dimensional insulating oxides. The crucial point of this project is that around room temperature the magnetic heat conductivity (of the order 100 W/Km) is as efficient as metallic heat conduction. Moreover, compared to conventional materials with high thermal conductivity, these novel compounds offer essential advantages: a) They are electrically insulating, b) heat is conducted primarily along one direction and c) heat is carried by localized spins which could allow for tunable heat conductivity at room temperature by manipulation of the spins with magnetic fields or light. Our scientific goal of exploiting this novel mode of heat transport for thermal management will be the basis for the research training in this ITN, which consists of 7 academic and 2 level-1 industrial partners. In order to tackle this scientific challenge in an multidisciplinary approach (physics, chemistry, materials science, computational science, electronic media), the fellows in our ITN will be trained on cutting edge experimental and theoretical techniques. In addition to training-through-research, the fellows will receive individual and collective training measures covering both scientific and complementary skills. We are especially dedicated to applying state-of-the-art training through electronic media which will reinforce the effectiveness and availability of training within this ITN.

Agency: Cordis | Branch: FP7 | Program: CP | Phase: FoF-ICT-2011.7.1 | Award Amount: 4.33M | Year: 2012

The BRIDLE project seeks to harness the power and efficiency of diode lasers to develop an affordable direct diode laser source for industrial applications requiring the cutting and welding of sheet metal. Specifically, BRIDLEs diode laser will have a power >2kW from a 100um diameter (NA <= 0.15) optical fibre and efficiency >40%. (This is ~2.5x more powerful, 10x brighter and 1.7x more efficient than the best spectral beam combined diode laser and ~30x times brighter than conventional diode lasers.) BRIDLE will focus on technologies suitable for manufacturability and cost scaling. Along with the increased power and brilliance, this will enable direct diode lasers to penetrate the metal processing market.\n\nBRIDLEs approach is modular, scalable and forward compatible. It begins with high brilliance mini-bars, whose emitters use intracavity filters to achieve 2-3x higher brilliance (~7W @ 0.8-1.5mm.mrad) than the best broad-area emitters (~7W @ 2.7mm.mrad). Fine and coarse spectral beam combining will further increase the brilliance by 5x and 3x increasing the total brilliance by 30-40x. Advanced coherent beam combining techniques will also be pursued to develop phase-coupled mini-bars with a nearly diffraction limited output power of 30W, allowing a further >4x improvement in spatial and spectral brilliance.\n\nBRIDLEs approach is chosen to be compatible with manufacturability and cost scaling requirements. The cost and complexity of the optical system are reduced by integrating optics inside the mini-bars (e.g. mode filters, DBR gratings for fine wavelength-spacing). Efficient, extremely low vertical divergence structures will lead to low-cost smile-insensitive assembly and low-loss optical coupling. The chosen packaging and beam combining techniques allow simple fabrication and good thermal management.\n\nBRIDLEs laser system will be validated for sheet metal cutting. The constituent sub-modules will target additional applications and markets.\n\nThe objectives of the BRIDLE project are of central importance to the photonics and manufacturing industries in Europe. BRIDLE technologies will enable the European diode laser and laser systems industries to maintain a leading global position. The industrial impact will extend across a wide range of industrial sectors, with European applications of this technology in the automotive, aerospace, manufacturing and materials processing sectors giving European manufacturers new advantages in an increasingly dynamic and competitive economic climate.\n\nThrough the exciting new technologies developed in this project, the European laser diode industry will be able to introduce new direct diode lasers into the materials processing markets at a lower cost and with significantly improved performance. European industry and society will be the first to benefit. The BRIDLE project will play a direct and important role in reinforcing economic growth, competitiveness, employment and sustainability.

Agency: Cordis | Branch: FP7 | Program: CSA | Phase: ICT-2011.9.5 | Award Amount: 1.71M | Year: 2011

Guardian Angels (GA) are future zero-power, intelligent, autonomous systems-of-systems featuring sensing, computation, and communication beyond human aptitudes. GA will assist humans from their infancy to old age in complex life situations and environments. Zero-power reflects system-of-systems ability to scavenge energy in dynamic environments by disruptive harvesting techniques. The project prepares zero-power technologies based on future energy-efficient technologies, heterogeneous design, and disruptive energy scavengers.\nThree zero-power generations of GAs are foreseen: Physical Guardian Angels are zero-power, on-body networks or implantable devices that monitor vital health signals and take appropriate actions to preserve human health. Environmental Guardian Angels extend monitoring to dynamic environments, using disruptive scavengers, personalized data communication, and first thinking algorithms. They are personal assistants that protect their wearers from environment dangers. Emotional Guardian Angels are intelligent personal companions with disruptive zero-power, manmachine interfaces deployed at large scale. They sense and communicate using non-verbal languages playing an important role in health, education, and security worldwide. This project addresses the following scientific challenges for energy-efficient visionary Guardian Angel autonomous systems: (i) energy-efficient computing (down to E=10-100kT), (ii) and communication (approaching the limit of 1pJ/bit), (iii) low-power sensing, (iv) disruptive scavenging (bio-inspired, thermoelectric, etc, targeting energy densities of tens of mW/cm2), and (v) zero-power man-machine interfaces. A selection of emerging technologies based on energy efficiency is proposed. We will also develop design tools that integrate electrical, mechanical, optical, thermal, and chemical simulation tools over length and time scales currently not achievable.

Agency: Cordis | Branch: FP7 | Program: MC-ITN | Phase: FP7-PEOPLE-2013-ITN | Award Amount: 3.23M | Year: 2013

WALL is a training network on the topic of domain walls in nanoscale magnetic structures, which will provide the next generation of researchers in this area of advanced technology. Domain walls (DWs) are the interfaces separating magnetic domains, their high speed manipulation in nanostructures will lead to the next generation of new and low power functional devices for computation and communication. The consortium that has come together to deliver this training is uniquely qualified to do so, consisting of world-leading experts on condensed matter physics and leading private companies, along with a range of associated partners spanning basic research, instrumentation development, industrial and consumer electronic products, and technology policy. The consortium provides a rich training environment that is both international and intersectoral, where our fellows will both study the cutting edge of science and technology in depth, but also come to appreciate the breadth of the field in terms of its intellectual challenges, commercial concerns, and relationship to societys need for ever more powerful information technologies with a reduced environmental footprint. This will enable them, in their future careers, to contribute to the strengthening of both the European Research Area and the European Information and Communication Technology (ICT) industry, particularly GreenIT, an especially important and growing sector for EU development.

Agency: Cordis | Branch: H2020 | Program: RIA | Phase: COMPET-05-2015 | Award Amount: 1.50M | Year: 2016

A new and exciting era of planetary space exploration started in 2000 with a plethora of in-situ and orbital missions in operation at terrestrial planets and small Solar System bodies. The characterisation of the surface of these planetary objects is one of the major goals of space exploration. In order to support these operations, reduction and analyses of the space mission data, the PTAL (Planetary Terrestrial Analogues Library) project aims to build and exploit a multi-instrument spectral data base and joint spectral interpretation tools. We will determine mineral alteration pathways for natural and artificial terrestrial analogue materials under well-defined and controlled experimental conditions. The impact of varying environmental conditions (e.g., gas pressure, temperature, pH-value) will be tested to better constrain the geochemical aspect of habitable conditions on Mars, the prime target of this project. All natural and artificial rock samples and their alteration products will be characterised for the spectral library with commercial and dedicated spacecraft instrumentation (NIR, RAMAN, LIBS) under laboratory conditions, and where possible on in-situ field campaigns. Both the understanding of alteration pathways and coordinated analyses of the surface of Mars from orbital and landed platforms with new and well-characterised spectral data will allow unprecedented interpretations of the climatic and environmental evolution for materials detected at new landing sites using our well-defined experimental parameter space for deriving conditions and evolution of environment and climate at Mars. Defining and characterising the ingredients for habitability at yet another planet will broaden our conception on the origin and evolution of life on our own planet, and prepare future investigations of forthcoming space missions in which several project members are highly involved.

Agency: Cordis | Branch: FP7 | Program: NOE | Phase: ICT-2007.2.1 | Award Amount: 7.78M | Year: 2008

PASCAL2 builds on the FP6 PASCAL Network of Excellence that has created a distributed institute pioneering principled methods of pattern analysis, statistical modeling, and computational learning (see http://www.pascal-network.org/). While retaining some of the structuring elements and mechanisms (such as the semi-annual Themes, and the Pump-Priming and Challenges programmes) of its predecessor NoE, PASCAL2 refocuses the institute towards the emerging challenges created by the ever expanding applications of adaptive systems technology and their central role in the development of artificial cognitive systems of different scales. Learning technology is key to, for instance, making robots more versatile, effective and autonomous, and to endowing machines with advanced interaction capabilities. The PASCAL2 Joint Programme of Activities (JPA) responds to these challenges not only through the research topics it addresses but also by engaging in technology transfer through an Industrial Club to effect rapid deployment of the developed technologies into a wide variety of applications. In addition, its Harvest sub-programme provides opportunities for close collaboration between academic and industry researchers. Other noteworthy outreach activities include curriculum development, brokerage of expertise, public outreach, and liaison with relevant R&D projects. Furthermore, PASCAL2 has adopted an open membership policy allowing for active inclusion in Network activities, of researchers working at non-beneficiary institutions.

Agency: Cordis | Branch: FP7 | Program: CP-FP | Phase: SSH-2009-3.2.1. | Award Amount: 3.11M | Year: 2010

One of the key changes in societal trends and lifestyles witnessed over the past few years has been the move on-line of many consumers and the way they have become increasingly sophisticated in their media consumption habits. Have these recent changes to consumer and commercial practices developed in such a way that consumers are (in)voluntarily signing away their fundamental right to privacy? This project (CONSENT) seeks to examine how consumer behaviour, and commercial practices are changing the role of consent in the processing of personal data. While consumer consent is a fundamental value on which the European market economy is based, the way consumer consent is obtained is questionable in popular user-generative/user-generated (UGC) online services (including sites like MySpace, YouTube and Facebook), whose commercial success depends to a large extent on the disclosure by their users of substantial amounts of personal data. There is an urgent need to study and analyse the changes in consumption behaviour and consumer culture arising from the emergence of UGC online services and how contractual, commercial and technical practices and other factors affect consumer choice and attitudes toward personal privacy in the digital economy. CONSENTs multidisciplinary team intends to carry out a status quo analysis of commercial practices, legal position and consumer attitudes, identifying criteria for fairness and best practices, and then create a toolkit for policy makers and corporate counsel which will enable them to address problem identified in the analysis. CONSENT will advance the knowledge base that underpins the formulation and implementation of policies and corporate procedures in the area of privacy and consumer protection with a view to informing policy-making in the European Union and to contribute to the development of European research communities in these areas.

Agency: Cordis | Branch: FP7 | Program: CP | Phase: ICT-2007.3.5 | Award Amount: 12.05M | Year: 2008

Photonics on CMOS is a candidate technology for applications where functional integration is needed for improving system performance while reducing size and cost.Functional demonstration of basic building blocks such as a laser, a detector, coupling, and link has been realized in previous research projects. As a next step the HELIOS project proposes to integrate photonics components with integrated circuits as a joint effort of major players of the European CMOS Photonics community, in order to enable an integrated design and fabrication chain that can be transferred to EU manufacturers.The objective of the project HELIOS is to combine a photonic layer with a CMOS circuit by different innovative means, using microelectronics fabrication processes.Different types of activities are foreseen:\tDevelopment of specific, high performance building blocks: WDM sources by III-V/Si heterogeneous integration, fast modulators and detectors, passive circuits and packaging. It also includes the development of dedicated TIA and modulators drivers.\tBuilding and optimization of the whole food chain to fabricate complex functional devices. Several components addressing different industrial needs will be built, including a 40Gb/s modulator, a 10x10 Gb/s transceiver, a Photonic QAM-10Gb/s wireless transmission system and a mixed analog and digital transceiver module for multifunction antennas.\tInvestigation of more promising but challenging alternative approaches. These concepts offer clear advantages in terms of integration on CMOS for the next generation of CMOS Photonics devices\tRoadmapping, dissemination and training, to strengthen the European research and industry in this field and to raise awareness of new users about the interest of CMOS Photonics.HELIOS will gather the major European CMOS Photonics and Electronics players and potential users. It will drive the European RTD in CMOS Photonics and pave the way for industrial development

Agency: Cordis | Branch: FP7 | Program: CP | Phase: ICT-2009.8.2 | Award Amount: 9.14M | Year: 2010

The overall objectives of the AQUTE project are\nA) To develop quantum technologies based on atomic, molecular and optical (AMO) systems for\n* scalable quantum computation;\n* entanglement-enabled technologies like metrology and sensing.\nB) To establish and exploit new interdisciplinary connections, coming from AMO physics, but also including concepts and experimental settings of solid state systems, in order to\n* reinforce interdisciplinary links at the frontiers of quantum information science, and other fields of physics or science in general;\n* conceive and realize novel hybrid systems that couple in a coherent way physically different quantum degrees of freedom.\nObj. A will be pursued along two complementary directions:\n* a bottom-up approach, where individually trapped atomic particles are combined into elementary general-purpose quantum processors including qubit interconnects;\n* a top-down approach, where many-particle atomic systems are employed to realize special-purpose quantum processors, for instance quantum simulators.\nGroundbreaking work in qualitatively new directions is also needed to lay the foundations for the future attainment of scalable fault-tolerant architectures. AQUTE will thus also\n* investigate new experimental systems that have become available in the laboratory and are of direct relevance for QIFT;\n* optimize existing and develop novel theoretical concepts for quantum processing.\nObj. B connects atomic quantum technologies for QIFT to a wider context, by\n* exploring hybrid approaches to QIFT beyond AMO physics;\n* improving connections between QIFT and science in general, following the emergence of a new quantum paradigm at the frontier of nanosciences and information sciences.\nThese research lines determine the structuring of the AQUTE workplan into four deeply interrelated Sub-Projects: Entangling gates and quantum processors, Hybrid quantum systems and interconnects, Quantum Simulators and Quantum Technologies.

Occlugel, French National Center for Scientific Research, University Paris Diderot, Assistance Publique Hopitaux De Paris and University Paris - Sud | Date: 2010-09-09

The present invention relates to a polymer obtained from the polymerization of: (i) at least one monomer of formula (I) (CH_(2)CR_(1))COK (I) wherein: K represents 0-Z or NHZ, Z representing (CR_(2)R_(3))_(m)CH_(3), (CH_(2)CH_(2)O)_(m)H, (CH_(2)CH_(2)O)_(m)CH_(3), (CH_(2))_(m)NR_(4)R_(5 )with m representing an integer from 1 to 30; R_(1), R_(2), R_(3), R_(4 )and R_(5 )independently represent H or a C1-C6 alkyl; and (ii) at least one bio-resorbable block copolymer cross-linker.

French National Center for Scientific Research, French National Institute for Agricultural Research, Institute Pasteur Paris and University Paris - Sud | Date: 2016-05-11

The present invention relates to N1-benzyl substituted pyrazoles as antiviral agents directed against respiratory syncytial virus (RSV).

French Institute of Health, Medical Research, University Paris - Sud and French National Institute for Agricultural Research | Date: 2012-06-15

The present invention relates to methods and pharmaceutical compositions for treating cancer. More specifically, the invention relates to a polypeptide isolated from Brevibacterium aurantiacum that shows methionine gamma-lyase and homocysteinase activities. The present invention also relates to the use of such a polypeptide for the treatment of cancer.

HarmonicSS vision is to create an International Network and Alliance of partners and cohorts, entrusted with the mission of addressing the unmet needs in primary Sjogren Syndrome; working together to create and maintain a platform with open standards and tools, designed to enable secure storage, governance, analytics, access control and controlled sharing of information at multiple levels along with methods to make results of analyses and outcomes comparable across centers and sustainable through Rheumatology associations. The overall idea of the HarmonicSS project is to bring together the largest well characterized regional, national and international longitudinal cohorts of patients with Primary Sjgrens Syndrome (pSS) including those participating in clinical trials, and after taking into consideration the ethical, legal, privacy and IPR issues for sharing data from different countries, to semantically interlink and harmonize them into an integrative pSS cohort structure on the cloud. Upon this harmonized cohort, services for big data mining, governance and visual analytics will be integrated, to address the identified clinical and health policy pSS unmet needs. In addition, tools for specific diagnostic procedures (e.g. ultrasonography image segmentation), patient selection for clinical trials and training will be also provided. The users of the HarmonicSS platform are researchers (basic/translational), clinicians, health policy makers and pharma companies. pSS is relevant not only due to its clinical impact but also as one of the few model diseases to link autoimmunity, cancer development (lymphoproliferation) and the pathogenetic role of infection. Thus, the study of pSS can facilitate research in many areas of medicine; for this reason, the possibility for sustainability and expandability of the platform is enhanced. Moreover, pSS has a significant impact on the healthcare systems, similar to that of rheumatoid arthritis.

French National Institute for Agricultural Research, French National Center for Scientific Research and University Paris - Sud | Date: 2013-05-23

A compound of general formula (I): in which X represents O, S, NH or an N-alkyl radical, R^(1 )and R^(2), identical or different, each represent H or a C_(1)-C_(10 )hydrocarbon radical, R^(1 )and R^(2 )not both representing H, R^(3 )represents a C_(1)-C_(10 )hydrocarbon radical, and R represents a phenyl radical monosubstituted or disubstituted by a substituent Y and, if applicable, a substituent Z, chosen from Cl, Br, I and CF_(3), or R represents a CR^(4)(R^(5)) radical in which R^(4 )represents an hydrocarbon radical and R^(5 )represents a linear or branched, saturated or unsaturated, hydrocarbon radical, optionally substituted, a COR^(6 )group or a CO_(2)R^(6 )group, where R^(6 )represents a hydrogen atom or a linear or branched, saturated or unsaturated, hydrocarbon radical. This compound can be used for the treatment of higher plants for controlling their growth and architecture.

Agency: Cordis | Branch: FP7 | Program: CP | Phase: ICT-2013.3.2 | Award Amount: 10.08M | Year: 2013

ACTPHAST is a unique one-stop-shop European access centre for photonics innovation solutions and technology support (Access CenTre for PHotonics innovAtion Solutions and Technology support). ACTPHAST will support and accelerate the innovation capacity of European SMEs by providing them with direct access to the expertise and state-of-the-art facilities of Europes leading photonics research centres, enabling companies to exploit the tremendous commercial potential of applied photonics. Technologies available within the consortium range from fibre optics and micro optics, to highly integrated photonic platforms, with capabilities extending from design through to full system prototyping. ACTPHAST has been geographically configured to ensure all of Europes SMEs can avail of timely, cost-effective, and investment-free photonics innovation support, and that the extensive range of capabilities within the consortium will impact across a wide range of industrial sectors, from communications to consumer-related products, biotechnology to medical devices. The access of predominantly SMEs to top-level experts and leading photonics technology platforms provided by the ACTPHAST consortium will be realised through focused innovation projects executed in relatively short timeframes with a critical mass of suitably qualified companies with high potential product concepts. As a result of these projects, the programme is expected to deliver a substantial increase in the revenues and employment numbers of the supported companies by supporting the development of new product opportunities and addressing emerging markets. Furthermore, through its extensive outreach activities, the programme will ensure there is an increased level of awareness and understanding across European industries of the technological and commercial potential of photonics.

Agency: Cordis | Branch: FP7 | Program: NOE | Phase: ICT-2011.1.1 | Award Amount: 5.55M | Year: 2012

NEWCOM# is a Network of Excellence (NoE) proposal submitted in response to challenge FP7-ICT-2011-8 1.1, Future Networks. A group of 14 partners in 14 different countries (12 of which come from the former FP7 NoE NEWCOM\\) decided to capitalize on the high degree of integration in research they already at-tained to build an NoE with the following objectives: i) to produce medium to long term results in the area of design and performance evaluation of wireless networks; ii) to strengthen the integration of partners re-search activities and agendas, both at the theoretical and experimental levels; iii) to foster Industry-academia cooperation, dissemination, and liaison by making academic research closer to industrial needs and interests; iv) to provide a unique training environment for a new generation of researchers in both theo-retical and experimental research; v) to contribute to the long-term sustainability of the NoE by creating a permanent environment for cooperative research.\nIn a Theoretical Research track, the NEWCOM# researchers will pursue long-term, interdisciplinary re-search on the most advanced aspects of wireless communications like Finding the Ultimate Limits of Com-munication Networks, Opportunistic and Cooperative Communications, Energy- and Bandwidth-Efficient Communications and Networking. A second track will be devoted to the EUropean lab of Wireless commu-nications for the future INternet, a federation of three sites in three European Countries that will host re-searchers working on a few general themes like Radio Interfaces, Internet of Things, and Flexible Communi-cation Terminals. The third track will have a number of initiatives to foster excellence like the creation of seasonal schools, a series of publication on journals and books, and an action directed towards strengthen-ing relations with European companies, which will participate to the NoE as Affiliate Partners, through a number of in-company dissemination events.

Agency: Cordis | Branch: FP7 | Program: NOE | Phase: ICT-2007.3.1 | Award Amount: 5.46M | Year: 2008

NANOSIL Network of Excellence aims to integrate at the European level the excellent European research laboratories and capabilities in order to strengthen scientific and technological excellence in the field of nanoelectronic materials and devices for terascale integrated circuits (ICs) and disseminate the results in a wide scientific and industrial community.NANOSIL will explore and assess the science and technological aspects of nanodevices and operational regimes relevant to n\4 technology node and beyond. It will provide a forward-look for the industry, enabling informed decisions to be taken on technology development in order to speed up technological innovation. It will encompass flagship projects on nanoscale CMOS and post-CMOS. The activities will thus be centred on the More Moore and Beyond-CMOS domains but natural links will also been established with the other ENIAC areas. Within the Network there are all the critical facilities and expertise to occupy and transcend this space. We will propose innovative concepts, technologies and device architectures- with fabrication down to the finest features, and utilising a wide spectrum of advanced deposition and processing capabilities, extensive characterisation and world leading device modelling. This work will be carried out through a network of joint processing, characterisation and modelling platforms. The consortium will work closely with and take steering from European industry. It will feed back data and know-how on materials and devices that deliver the required performance. This critical interaction will strengthen European integration in nanoelectronics, help in decision-making by industry and ensure that Europe remains at the forefront of nanoelectronics for the next 2 3 decades.

Agency: Cordis | Branch: FP7 | Program: CP-IP | Phase: NMP-2009-4.0-3 | Award Amount: 11.70M | Year: 2010

Medical diagnosis is currently undergoing a major revolution due to the fast discovery of molecular biomarkers, and the development of multimodal metabiomarker signatures. Progress, however, is hindered by low abundance of many biomarkers of interest in body fluids, in absolute concentration and with regard to other biomolecules. The aim of the present project is to apply these progresses in biotechnology, nanoparticle synthesis, and nano-instrumentation to the development of fully integrated lab-on chip instruments able to perform elaborate multimodal biomarker analysis on a routine basis and at the ultrasensitive level required to allow minimally invasive tests. In particular, we aim at overcoming a major bottleneck on the path to this objective, which was identified in a previous project in the HEALTH priority: no satisfactory solution currently exists to bridge the several orders of magnitude between the nanoscale volumes at which ultrasensitive new generation sensors operate, and the often millilitre volumes of samples in which the molecules of interest must be found. For this, we shall combine innovations in pre-concentration, micro and nanofluidics, self-assembly, micro-nanofabrication, and nanodetection. The project will develop a generic, multipurpose, platform of compatible enabling technologies, and integrate them into devices. In order to maximize impact and societal benefit, the project will be validated on an application of major interest for health, namely the early detection of biomarkers for neurodegenerative diseases (including Alzheimer), with special emphasis on subtyping of these diseases for improved treatment strategies. The consortium includes a multidisciplinary group of technology developers, three leading biomedical groups in clinical neuroscience for definition of specifications and end-user pre-clinical validation, and three research-oriented SMEs in biotechnology, nanosensing and microfluidics.

Agency: Cordis | Branch: FP7 | Program: CP-IP | Phase: HEALTH.2011.2.3.1-3 | Award Amount: 15.65M | Year: 2011

Antibiotics are a mainstay of public health, but their use has increased exponentially leading to the emergence of antibiotic resistance. The R-GNOSIS (Resistance in Gram-Negative Organisms: Studying Intervention Strategies) project combines 5 international clinical studies, all supported by highly innovative microbiology, mathematical modelling and data-management, to determine - in the most relevant patient populations - the efficacy and effectiveness of cutting-edge interventions to reduce carriage, infection and spread of Multi-Drug Resistant Gram-negative Bacteria (MDR-GNB). All work-packages will progress science beyond the state-of-the-art in generating new and translational clinically relevant knowledge, through hypothesis-driven studies focussed on patient-centred outcomes. The 5 clinical studies will investigate the following interventions: A Point-Of-Care-Testing guided management strategy to improve appropriate antibiotic prescription for uncomplicated UTI in primary care. Gut decolonization in outpatients with intestinal carriage of MDR-GNB. A test and prescribe strategy, based on rapid diagnostic testing of faeces for MDR-GNB to optimize antibiotic prophylaxis in colo-rectal surgery. Contact Isolation of patients with ESBL-producing Enterobacteriaceae in general hospital wards. Three Decolonization strategies in ICUs. Seven laboratories across Europe will perform microbiological analyses, as well as unique quantitative experiments. All information will be integrated by 3 groups of mathematical modellers into highly innovative models to better understand and predict future trends and effects of interventions. The studies and analyses proposed in R-GNOSIS will generate a step-change in identifying evidence-based preventive measures and clinical guidance for primary care and hospital-based physicians and health-care authorities, to combat the spread and impact of infections caused by MDR-GNB in Europe.

Agency: Cordis | Branch: FP7 | Program: CP-FP | Phase: HEALTH.2011.2.3.1-1 | Award Amount: 7.72M | Year: 2012

Background. Ventilator-associated pneumonia (VAP) is one of the most common and severe hospital-adquired infections, and multidrugresistant gram-negative bacilli (MDR-GNB) constitute the main etiology in many countries. Inappropriate empiric antimicrobial treatment is associated with increased mortality. In this context, the empirical treatment of choice for VAP is unknown. Colistin, and old drug, is now the antimicrobial with greatest in vitro activity against MDR-GNB. However, no randomized clinical trial with colistin has been carried out. Additional aspects of colistin are also not well known, such as the appearance of resistant strains or alterations in the intestinal microbiome during treatment. Furthermore, conventional microbiological techniques take 48 to 72 hours to identify pathogens and determine their susceptibility. This is too long if empiric treatment is inappropriate. Objetives. The overall goal is the optimisation of the treatment of VAP caused by MDR-GNB, by defining a gold standard empiric therapy and reducing the period of time needed for the determination of the etiology and susceptibility of pathogens. Methods. MagicBullet proposes a randomized, open label, multicenter, clinical trial to compare the safety and efficacy of colistin vs. meropenem, both combined with levofloxacin, for empirical treatment of VAP. The pharmacokinetic and pharmacodynamic characteristics of colistin will be determined. Evaluation of the impact of the both treatments in the intestinal microbiome of patients and in the Ventilator-associated pneumonia (VAP) is one of the most common and severe hospital-adquired infections, and multidrug-resistant gramnegative bacilli (MDR-GNB) constitute the main etiology in many countries. Inappropriate empiric antimicrobial treatment is associated with increased mortality. In this context, the empirical treatment of choice for VAP is unknown. Colistin, and old drug, is now the antimicrobial with greatest in vitro activity against MDR-GNB. However, no randomized clinical trial with colistin has been carried out. Additional aspects of colistin are also not well known, such as the appearance of resistant strains or alterations in the intestinal microbiome during treatment. Furthermore, conventional microbiological techniques take 48 to 72 hours to identify pathogens and determine their susceptibility. This is too long if empiric treatment is inappropriate.

Agency: Cordis | Branch: FP7 | Program: CP-FP | Phase: Fission-2009-7.0.4 | Award Amount: 1.86M | Year: 2010

An innovative molten salt reactor concept, the MSFR (Molten Salt Fast Reactor) is developed by CNRS (France) since 2004. Based on the particularity of using a liquid fuel, this concept is derived from the American molten salt reactors (included the demonstrator MSRE) developed in the 1960s. The major drawbacks of these designs were (1) a short lifetime of the graphite blocks, (2) a reactor fuelled with 233U, not a natural fissile isotope, (3) a salt constituted of a high chemical toxic element: BeF2, and (4) a fuel reprocessing flux of 4000 liters per day required reaching a high breeding gain. However, this concept is retained by the Generation IV initiative, taking advantages of using a liquid fuel which allows more manageable on-line core control and reprocessing, fuel cycle flexibility (U or Th) and minimization of radiotoxic nuclear wastes. In MSFR, MSR concept has been revisited by removing graphite and BeF2. The neutron spectrum is fast and the reprocessing rate strongly reduced down to 40 liters per day to get a positive breeding gain. The reactor is started with 233U or with a Pu and minor actinides (MA) mixture from PWR spent fuel. The MA consumption with burn-up demonstrates the burner capability of MSFR. The objective of this project is to propose a design of MSFR in 2012 given the best system configuration issued from physical, chemical and material studies, for the reactor core, the reprocessing unit and the wastes conditioning. By this way, demonstration that MSFR can satisfy the goals of Gen IV, in terms of sustainability (Th breeder), non proliferation (integrated fuel cycle, multi-recycling of actinides), resources (close U/Th fuel cycle, no uranium enrichment), safety (no reactivity reserve, strongly negative feedback coefficient) and waste management (actinide burner) will be done

Agency: Cordis | Branch: FP7 | Program: CP-FP | Phase: NMP.2013.2.2-4 | Award Amount: 6.10M | Year: 2013

Energy harvesting at low frequency has proven to be difficult to achieve in the past because of the properties of the materials that the devices are fabricated from. In particular the stiffness of conventional silicon and all piezoelectric materials makes it exceedingly difficult to make a system that can operate below 100Hz. There are many sources of low frequency vibrations e.g. human motion, the motion of ships, and traffic; so an Energy Harvester that can operate in this frequency range would have a large commercial potential and extensive opportunities for future exploitation. This multi disciplinary project proposal addresses the lack of durable energy harvesting systems in this frequency range. With primary objectives of the project being the development of materials and devices for; Low frequency tunable energy harvesting device and High energy density compact supercapacitors for energy storage with secondary objectives being: - The necessary electronics to connect them and make them work efficiently - Packaging technologies that will integrate the full system and make it biocompatible - A study of component reliability and models that can project their lifetime - An end of life study and an environmental impact assessment Perpetually self powered electronic systems that can be implanted into the human body is the application area that we have targeted for demonstration of this technology, because there are a clear set of requirements which will motivate the design, fabrication and test of the system under consideration. The two primary objectives present a range of novel and substantial materials challenges in both making the components, achieving a reliable unattended operational extended lifetime and ensuring that the devices are not toxic to the host that they are implanted into. While the secondary ones will facilitate an appropriate demonstration of the technology and ensure its usefulness after the project has been completed.

Agency: Cordis | Branch: FP7 | Program: CP | Phase: ICT-2011.9.9 | Award Amount: 11.78M | Year: 2013

The overarching goal of our project is to develop systems based on direct and deterministic interactions between individual quantum entities, which by involving large-scale entanglement can outperform classical systems in a series of relevant applications.\nWe plan to achieve that by improving technologies from atomic, molecular and optical physics as well as from solid-state physics, and by developing new ones, including combinations across those different domains. We will explore a wide range of experimental platforms as enabling technologies: from cold collisions or Rydberg blockade in neutral atoms to electrostatic or spin interactions in charged systems like trapped ions and quantum dots; from photon-phonon interactions in nano-mechanics to photon-photon interactions in cavity quantum electrodynamics and to spin-photon interactions in diamond color centers.\nWe will work on two deeply interconnected lines to build experimentally working implementations of quantum simulators and of quantum interfaces. This will enable us to conceive and realize applications exploiting those devices for simulating important problems in other fields of physics, as well as for carrying out protocols outperforming classical communication and measurement systems.

Agency: Cordis | Branch: FP7 | Program: CPCSA | Phase: INFRA-2010-1.2.1 | Award Amount: 70.14M | Year: 2010

Scientific research is no longer conducted within national boundaries and is becoming increasing dependent on the large-scale analysis of data, generated from instruments or computer simulations housed in trans-national facilities, by using e Infrastructure (distributed computing and storage resources linked by high-performance networks).\nThe 48 month EGI-InSPIRE project will continue the transition to a sustainable pan-European e-Infrastructure started in EGEE-III. It will sustain support for Grids of high-performance and high-throughput computing resources, while seeking to integrate new Distributed Computing Infrastructures (DCIs), i.e. Clouds, SuperComputing, Desktop Grids, etc., as they are required by the European user community. It will establish a central coordinating organisation, EGI.eu, and support the staff throughout Europe necessary to integrate and interoperate individual national grid infrastructures. EGI.eu will provide a coordinating hub for European DCIs, working to bring existing technologies into a single integrated persistent production infrastructure for researchers within the European Research Area.\nEGI-InSPIRE will collect requirements and provide user-support for the current and new (e.g. ESFRI) users. Support will also be given for the current heavy users as they move their critical services and tools from a central support model to ones driven by their own individual communities. The project will define, verify and integrate within the Unified Middleware Distribution, the middleware from external providers needed to access the e-Infrastructure. The operational tools will be extended by the project to support a national operational deployment model, include new DCI technologies in the production infrastructure and the associated accounting information to help define EGIs future revenue model.

Agency: Cordis | Branch: FP7 | Program: CPCSA | Phase: INFRA-2007-1.2-03 | Award Amount: 49.02M | Year: 2008

A globally distributed computing Grid now plays an essential role for large-scale, data intensive science in many fields of research. The concept has been proven viable through the Enabling Grids for E-sciencE project (EGEE and EGEE-II, 2004-2008) and its related projects. EGEE-II is consolidating the operations and middleware of this Grid for use by a wide range of scientific communities, such as astrophysics, computational chemistry, earth and life sciences, fusion and particle physics. Strong quality assurance, training and outreach programmes contribute to the success of this production Grid infrastructure. \nBuilt on the pan-European network GANT2, EGEE has become a unique and powerful resource for European science, allowing researchers in all regions to collaborate on common challenges. Worldwide collaborations have extended its reach to the benefit of European science.\nThe proposed EGEE-III project has two clear objectives that are essential for European research infrastructures: to expand, optimize and simplify the use of Europes largest production Grid by continuous operation of the infrastructure, support for more user communities, and addition of further computational and data resources; to prepare the migration of the existing Grid from a project-based model to a sustainable federated infrastructure based on National Grid Initiatives. \nBy strengthening interoperable, open source middleware, EGEE-III will actively contribute to Grid standards, and work closely with businesses to ensure commercial uptake of the Grid, which is a key to sustainability. \nFederating its partners on a national or regional basis, EGEE-III will have a structuring effect on the European Research Area. In particular, EGEE-III will ensure that the European Grid does not fragment into incompatible infrastructures of varying maturity. EGEE-III will provide a world class, coherent and reliable European Grid, ensuring Europe remains at the forefront of scientific excellence.

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.

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.

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.

Wang B.,University Paris - Sud | Lalanne P.,University Paris - Sud
Applied Physics Letters | Year: 2010

In contrast to earlier classical studies that analyze the surface Bloch modes supported by metallic gratings composed of slits as collective surface-plasmon-polaritons (SPPs) resonances (or poles) of the entire periodic problem, we study the normalized rate of SPPs that are locally launched on every individual ridge of metallic lamellar gratings. With this " microscopic" description at the unit-cell level, we further explain how these individual SPPs constructively interfere to build up the classical collective resonances. The approach, which combines analytical treatments and fully-vectorial computations, shines new light on an important and classical phenomenon of grating diffraction. © 2010 American Institute of Physics.

Coite F.,University Paris - Sud | Coite F.,University of Paris Pantheon Sorbonne | Coite F.,Hoipital University Necker Enfants Malades
ACS Chemical Neuroscience | Year: 2013

Since its identification, 75 years ago, the monoamine serotonin (5-HT) has attracted considerable attention toward its role as a neurotransmitter in the central nervous system. Yet, increasing evidence, from a growing number of research groups, substantiates the fact that 5-HT regulates important nonneuronal functions. Peripheral 5-HT, synthesized by the enzyme tryptophan hydroxyase (Tph) in intestinal cells, was assumed to be distributed throughout the entire body by blood platelets and to behave as a pleiotropic hormone. A decade ago, generation of a mouse model devoid of peripheral 5-HT lead to the discovery of a second isoform of the enzyme Tph and also suggested that 5-HT might act as a local regulator in various organs. The objective of this review is to highlight the newly discovered functions played by the monoamine using the Tph1 KO murine model and to outline current findings that led to the discovery of complete serotonergic systems in unexpected organs. Within an organ, both the presence of local Tph enzymatic activity and serotonergic components are of particular importance as they support the view that 5-HT meets the criteria to be qualified as a monoamine with a paracrine/autocrine function. © 2012 American Chemical 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.

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.

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.

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.

Missenard Y.,University Paris - Sud | Cadoux A.,CNRS Earth Sciences Institute of Orléans
Terra Nova | Year: 2012

The Moroccan lithosphere is characterized by an anomalously thinned area, located beneath the Atlas domains, which forms a singular narrow NE-SW directed strip overlain by Cenozoic alkaline volcanism. The origin of this thinning and volcanism is still a matter of debate. The proposed models invoke processes either related to the Mediterranean slab or mantle plumes. Herein, we propose an alternative Edge-Driven Convection (EDC) model involving small-scale convection at the boundary between the West-African craton and the Atlas lithosphere. Our comparison of the Atlas lithosphere velocity and volcanism episodes during the last 80Ma points out that volcanism occurs when plate moves at velocities c.<1cma -1, a velocity sufficiently low to trigger EDC. This is the first process that could explain the c. 20Ma volcanism shutdown separating the two volcanic episodes of the Atlas. In addition, it may successfully account for the lithosphere thinning location and geometry and volcanism geochemistry. © 2011 Blackwell Publishing Ltd.

Espeli M.,University Paris - Sud | Smith K.G.C.,University of Cambridge | Clatworthy M.R.,University of Cambridge
Immunological Reviews | Year: 2016

Autoimmune diseases are characterized by adaptive immune responses against self-antigens, including humoral responses resulting in the production of autoantibodies. Autoantibodies generate inflammation by activating complement and engaging Fcγ receptors (FcγRs). The inhibitory receptor FcγRIIB plays a central role in regulating the generation of autoantibodies and their effector functions, which include activation of innate immune cells and the cellular arm of the adaptive immune system, via effects on antigen presentation to CD4 T cells. Polymorphisms in FcγRIIB have been associated with susceptibility to autoimmunity but protection against infections in humans and mice. In the last few years, new mechanisms by which FcγRIIB controls the adaptive immune response have been described. Notably, FcγRIIB has been shown to regulate germinal center B cells and dendritic cell migration, with potential impact on the development of autoimmune diseases. Recent work has also highlighted the implication of FcγRIIB on the regulation of the innate immune system, via inhibition of Toll-like receptor- and complement receptor-mediated activation. This review will provide an update on the role of FcγRIIB in adaptive immune responses in autoimmunity, and then focus on their emerging function in innate immunity. © 2016 John Wiley & Sons A/S.

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.

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.

Elmqvist N.,Purdue University | Fekete J.-D.,University Paris - Sud
IEEE Transactions on Visualization and Computer Graphics | Year: 2010

We present a model for building, visualizing, and interacting with multiscale representations of information visualization techniques using hierarchical aggregation. The motivation for this work is to make visual representations more visually scalable and less cluttered. The model allows for augmenting existing techniques with multiscale functionality, as well as for designing new visualization and interaction techniques that conform to this new class of visual representations. We give some examples of how to use the model for standard information visualization techniques such as scatterplots, parallel coordinates, and node-link diagrams, and discuss existing techniques that are based on hierarchical aggregation. This yields a set of design guidelines for aggregated visualizations. We also present a basic vocabulary of interaction techniques suitable for navigating these multiscale visualizations. © 2010 IEEE.

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.

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.

Tissot A.,University Paris - Sud | Enachescu C.,Al. I. Cuza University | Boillot M.-L.,University Paris - Sud
Journal of Materials Chemistry | Year: 2012

Microcrystals of FeII(phen)2(NCS)2 (phen = 1,10-phenanthroline), isolated by solvent-induced precipitation, were dispersed in glassy or semicrystalline matrices and subjected to thermal or chemical treatments. Interactions occurring between crystals and their macromolecular (or molecular) surroundings were revealed by drastic alteration of the first-order spin-transition afforded by this material. Depending on matrices and experimental treatments, the cooperativity in particles dispersion can be dampened, resulting in a more gradual transition or enhanced, providing a large hysteresis. The hysteresis broadening was also demonstrated by the incorporation of another first-order transition molecular material (bulk) into similar matrices. The different features associated with the in-polymer dispersions are accounted for in the framework of a mechanoelastic model based on a Monte-Carlo standard procedure. © 2012 The Royal Society of Chemistry.

Lombard J.,University Paris - Sud | Lopez-Garcia P.,University Paris - Sud | Moreira D.,University Paris - Sud
Molecular Biology and Evolution | Year: 2012

Fatty acids (FAs) are major building blocks of membrane phospholipids in bacteria and eukaryotes. Their presumed absence in archaea led to propose a late origin in bacteria and eukaryotes and that the last common ancestor of living organisms (the cenancestor) was devoid of both FA and phospholipid membranes. However, small FA amounts and homologs of bacterial FA biosynthesis enzymes are found in archaea. We have investigated the origin of these archaeal enzymes using phylogenomic analyses of all enzymes of the main bacterial FA biosynthesis pathway. Our results suggest that modern archaea and their last common ancestor possessed a complete pathway except for the acyl carrier protein (ACP) processing machinery, which evolved in the bacterial lineage. This has not only implications for archaeal physiology but also opens the possibility for the presence of ACP-independent FA synthesis in the cenancestor, which may have been endowed with FA-phospholipid membranes. © 2012 The Author.

Deschamps P.,University Paris - Sud | Moreira D.,University Paris - Sud
Genome Biology and Evolution | Year: 2012

Photosynthetic diatom plastids have long been suggested to have originated by the secondary endosymbiosis of a red alga. However, recent phylogenomic studies report a high number of diatom nuclear genes phylogenetically related to green algal and green plant genes. These were interpreted as endosymbiotic gene transfers (EGT) from a cryptic green algal endosymbiosis. We reanalyzed this issue using a larger set of red algal genomic data. We show that previous studies suffer from a taxonomic sampling bias and point out that a majority of gene phylogenies are either poorly resolved or do not describe EGT events. We finally show that genes having a complete descent from cyanobacteria to diatoms through primary and secondary EGTs have been mostly transferred via a red alga. We conclude that, even if some diatom genes still support a putative green algal origin, these are not sufficient to argue for a cryptic green algal secondary endosymbiosis. © 2012 The Author(s).

Moller A.P.,University Paris - Sud | Garamszegi L.Z.,CSIC - Doñana 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.

Sampaio J.,University Paris - Sud | Cros V.,University Paris - Sud | Rohart S.,University Paris - Sud | Thiaville A.,University Paris - Sud | Fert A.,University Paris - Sud
Nature Nanotechnology | Year: 2013

Magnetic skyrmions are topologically stable spin configurations, which usually originate from chiral interactions known as Dzyaloshinskii-Moriya interactions. Skyrmion lattices were initially observed in bulk non-centrosymmetric crystals, but have more recently been noted in ultrathin films, where their existence is explained by interfacial Dzyaloshinskii-Moriya interactions induced by the proximity to an adjacent layer with strong spin-orbit coupling. Skyrmions are promising candidates as information carriers for future information-processing devices due to their small size (down to a few nanometres) and to the very small current densities needed to displace skyrmion lattices. However, any practical application will probably require the creation, manipulation and detection of isolated skyrmions in magnetic thin-film nanostructures. Here, we demonstrate by numerical investigations that an isolated skyrmion can be a stable configuration in a nanostructure, can be locally nucleated by injection of spin-polarized current, and can be displaced by current-induced spin torques, even in the presence of large defects.

de Silva J.P.,University Paris - Sud
The European physical journal. E, Soft matter | Year: 2011

We study the influence of nanoparticle doping on the lyotropic liquid crystalline phase of the industrial surfactant Brij®30 (CE) and water, doped with spherical polyoxometalate nanoparticles smaller than the characteristic dimensions of the host lamellar phase. We present viscometry and in situ rheology coupled with small-angle X-ray scattering data that show that, with increasing doping concentration, the nanoparticles act to decrease the shear viscosity of the lamellar phase, and that a shear-induced transition to a multilamellar vesicle "onion" phase is pushed to higher shear rates, and in some cases completely suppressed. X-ray data reveal that the nanoparticles remain encapsulated within the membranes of the vesicles, thus indicating a viable method for the fabrication of nanoparticle incorporating organic vesicles.

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.

Pennycook S.J.,Oak Ridge National Laboratory | Colliex C.,University Paris - Sud
MRS Bulletin | Year: 2012

In the scanning transmission electron microscope, multiple signals can be simultaneously collected, including the transmitted and scattered electron signals (bright field and annular dark field or Z-contrast images), along with spectroscopic signals such as inelastically scattered electrons and emitted photons. In the last few years, the successful development of aberration correctors for the electron microscope has transformed the field of electron microscopy, opening up new possibilities for correlating structure to functionality. Aberration correction not only allows for enhanced structural resolution with incident probes into the sub-Ãngstrom range, but can also provide greater probe currents to facilitate mapping of intrinsically weak spectroscopic signals at the nanoscale or even the atomic level. In this issue of MRS Bulletin, we illustrate the power of the new generation of electron microscopes with a combination of imaging and spectroscopy. We show the mapping of elemental distributions at atomic resolution and also the mapping of electronic and optical properties at unprecedented spatial resolution, with applications ranging from graphene to plasmonic nanostructures, and oxide interfaces to biology. © 2012 Materials Research 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.

Castanier C.,University Paris - Sud | Garcin D.,University of Geneva | Vazquez A.,University Paris - Sud | Arnoult D.,University Paris - Sud
EMBO Reports | Year: 2010

The intracellular retinoic acid-inducible gene I-like receptors (RLRs) sense viral ribonucleic acid and signal through the mitochondrial protein mitochondrial antiviral signalling (MAVS) to trigger the production of type I interferons and proinflammatory cytokines. In this study, we report that RLR activation promotes elongation of the mitochondrial network. Mimicking this elongation enhances signalling downstream from MAVS and favours the binding of MAVS to stimulator of interferon genes, an endoplasmic reticulum (ER) protein involved in the RLR pathway. By contrast, enforced mitochondrial fragmentation dampens signalling and reduces the association between both proteins. Our finding that MAVS is associated with a pool of mitofusin 1, a protein of the mitochondrial fusion machinery, suggests that MAVS is capable of regulating mitochondrial dynamics to facilitate the mitochondria-ER association required for signal transduction. Importantly, we observed that viral mitochondria-localized inhibitor of apoptosis, a cytomegalovirus (CMV) antiapoptotic protein that promotes mitochondrial fragmentation, inhibits signalling downstream from MAVS, suggesting a possible new immune modulation strategy of the CMV. © 2010 EUROPEAN MOLECULAR BIOLOGY ORGANIZATION.

Djouadi A.,University Paris - Sud | Moreau G.,University Paris - Sud
European Physical Journal C | Year: 2013

Using the full set of the LHC Higgs data from the runs at 7 and 8 TeV center of mass energies that have been released by the ATLAS and CMS collaborations, we determine the couplings of the Higgs particle to fermions and gauge bosons as well as its parity or CP composition. We consider ratios of production cross sections times decay branching fractions in which the theoretical (and some experimental) uncertainties as well as some ambiguities from new physics cancel out. A fit of both the signal strengths in the various search channels that have been conducted, H→ZZ,WW,γγ,ττ and bb̄, and their ratios shows that the observed ∼126 GeV particle has couplings to fermions and gauge bosons that are Standard Model-like already at the 68 % confidence level (CL). From the signal strengths in which the theoretical uncertainty is taken to be a bias, the particle is shown to be at most 68 % CP-odd at the 99 %CL and the possibility that it is a pure pseudoscalar state is excluded at the 4σ level when including both the experimental and theoretical uncertainties. The signal strengths also measure the invisible Higgs decay width which, with the same type of uncertainty analysis, is shown to be ΓH invΓH SM ≤0.52 at the 68 %CL. © 2013 Springer-Verlag Berlin Heidelberg and Società Italiana di Fisica.

Michalski J.R.,Planetary Science Institute | Michalski J.R.,University Paris - Sud | Niles P.B.,NASA
Nature Geoscience | Year: 2010

The surface of Mars is cold, dry, oxidizing, acidic and inhospitable to life. Similar conditions may have persisted for billions of years, suggesting that the best place to search for habitable environments is the subsurface. One hint of habitable conditions at depth is the presence of atmospheric methane, which may have formed through hydrothermal processes in the crust in the presence of CO2. The observation of hydrated minerals excavated by some impact craters suggests that ancient hydrothermal systems may have existed in the subsurface, but until now, none of those deposits has been linked to carbonate minerals and CO2 -rich environments. Previous detections of carbonate minerals that could be linked to an ancient CO2 -rich surface environment have been sparse. Here we show spectral evidence for carbonate- and phyllosilicate-bearing, layered and foliated bedrock exhumed from deep (about 6km) within the martian crust by a meteor impact. The mineral assemblage, textural properties and geologic context of the deposits indicate that these rocks are probably ancient sediments that were metamorphosed during burial by younger volcanic materials from the nearby Syrtis Major volcano. We suggest that these buried layered carbonates might be only a small part of a much more extensive ancient carbonate sedimentary record that has been buried by volcanic resurfacing and impact ejecta. Our discovery may help explain the origin of other carbonates on Mars and indicates a high-priority site for future exobiological exploration. © 2010 Macmillan Publishers Limited. All rights reserved. © 2010 Macmillan Publishers Limited. All rights reserved.

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.

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.

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?

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.

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.

Codogno P.,University Paris - Sud | Mehrpour M.,University Paris - Sud | Proikas-Cezanne T.,University of Tübingen
Nature Reviews Molecular Cell Biology | Year: 2012

The autophagosome is the central organelle in macroautophagy, a vacuolar lysosomal catabolic pathway that degrades cytoplasmic material to fuel starving cells and eliminates intracellular pathogens. Macroautophagy has important physiological roles during development, ageing and the immune response, and its cytoprotective function is compromised in various diseases. A set of autophagy-related (ATG) proteins is hierarchically recruited to the phagophore, the initial membrane template in the construction of the autophagosome. However, recent findings suggest that macroautophagy can also occur in the absence of some of these key autophagy proteins, through the unconventional biogenesis of canonical autophagosomes. Such alternatives to the evolutionarily conserved scheme might provide additional therapeutic opportunities.

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.

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.

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.

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.

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.

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++.

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.

Angelova A.,University Paris - Sud | Angelov B.,University of Aarhus | Angelov B.,Czech Institute of Macromolecular Chemical | Angelov B.,Bulgarian Academy of Science | And 3 more authors.
Accounts of Chemical Research | Year: 2011

Lipids and lipopolymers self-assembled into biocompatible nano- and mesostructured functional materials offer many potential applications in medicine and diagnostics. In this Account, we demonstrate how high-resolution structural investigations of bicontinuous cubic templates made from lyotropic thermosensitive liquid-crystalline (LC) materials have initiated the development of innovative lipidopolymeric self-assembled nanocarriers. Such structures have tunable nanochannel sizes, morphologies, and hierarchical inner organizations and provide potential vehicles for the predictable loading and release of therapeutic proteins, peptides, or nucleic acids. This Account shows that structural studies of swelling of bicontinuous cubic lipid/water phases are essential for overcoming the nanoscale constraints for encapsulation of large therapeutic molecules in multicompartment lipid carriers.For the systems described here, we have employed time-resolved small-angle X-ray scattering (SAXS) and high-resolution freeze-fracture electronic microscopy (FF-EM) to study the morphology and the dynamic topological transitions of these nanostructured multicomponent amphiphilic assemblies. Quasi-elastic light scattering and circular dichroism spectroscopy can provide additional information at the nanoscale about the behavior of lipid/protein self-assemblies under conditions that approximate physiological hydration.We wanted to generalize these findings to control the stability and the hydration of the water nanochannels in liquid-crystalline lipid nanovehicles and confine therapeutic biomolecules within these structures. Therefore we analyzed the influence of amphiphilic and soluble additives (e.g. poly(ethylene glycol)monooleate (MO-PEG), octyl glucoside (OG), proteins) on the nanochannels size in a diamond (D)-type bicontinuous cubic phase of the lipid glycerol monooleate (MO). At body temperature, we can stabilize long-living swollen states, corresponding to a diamond cubic phase with large water channels. Time-resolved X-ray diffraction (XRD) scans allowed us to detect metastable intermediate and coexisting structures and monitor the temperature-induced phase sequences of mixed systems containing glycerol monooleate, a soluble protein macromolecule, and an interfacial curvature modulating agent. These observed states correspond to the stages of the growth of the nanofluidic channel network.With the application of a thermal stimulus, the system becomes progressively more ordered into a double-diamond cubic lattice formed by a bicontinuous lipid membrane. High-resolution freeze-fracture electronic microscopy indicates that nanodomains are induced by the inclusion of proteins into nanopockets of the supramolecular cubosomic assemblies. These results contribute to the understanding of the structure and dynamics of functionalized self-assembled lipid nanosystems during stimuli-triggered LC phase transformations. © 2010 American Chemical Society.

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.

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.

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).

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.

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.

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.

Cassan E.,University Paris - Sud | Do K.-V.,University Paris - Sud
Journal of the Optical Society of America B: Optical Physics | Year: 2011

We propose an analytical approach to the study of graded photonic crystals operating in the metamaterial regime. Relationships are given to predict the optical index map and hole-drilling distribution required to make light follow a prescribed path. The method is applied to proof-of-concept structures based on silicon-on-insulator technology. Light propagation is studied using FDTD simulation to verify the light trajectory, study the influence of extended light beams, and evaluate the robustness of the semiclassical approach based on the equations of Hamiltonian optics. The overall approach can be used for the straightforward design of new optical functionalities within the photonic metamaterial regime. © 2011 Optical Society of America.

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.

Garcia V.,University Paris - Sud | Bibes M.,University Paris - Sud
Nature Communications | Year: 2014

Computer memory that is non-volatile and therefore able to retain its information even when switched off enables computers that do not need to be booted up. One of the technologies for such applications is ferroelectric random access memories, where information is stored as ferroelectric polarization. To miniaturize such devices to the size of a few nanometres, ferroelectric tunnel junctions have seen considerable interest. There, the electric polarization determines the electrical resistance of these thin films, switching the current on and off. With control over other parameters such as magnetism also being possible, ferroelectric tunnel junctions represent a promising and flexible device design. © 2014 Macmillan Publishers Limited.

Forrester P.J.,University of Melbourne | Majumdar S.N.,University Paris - Sud | Schehr G.,University Paris - Sud
Nuclear Physics B | Year: 2011

We study a system of N non-intersecting Brownian motions on a line segment [0,L] with periodic, absorbing and reflecting boundary conditions. We show that the normalized reunion probabilities of these Brownian motions in the three models can be mapped to the partition function of two-dimensional continuum Yang-Mills theory on a sphere respectively with gauge groups U(N), Sp(2N) and SO(2N). Consequently, we show that in each of these Brownian motion models, as one varies the system size L, a third order phase transition occurs at a critical value L=Lc(N)~N in the large N limit. Close to the critical point, the reunion probability, properly centered and scaled, is identical to the Tracy-Widom distribution describing the probability distribution of the largest eigenvalue of a random matrix. For the periodic case we obtain the Tracy-Widom distribution corresponding to the GUE random matrices, while for the absorbing and reflecting cases we get the Tracy-Widom distribution corresponding to GOE random matrices. In the absorbing case, the reunion probability is also identified as the maximal height of N non-intersecting Brownian excursions ("watermelons" with a wall) whose distribution in the asymptotic scaling limit is then described by GOE Tracy-Widom law. In addition, large deviation formulas for the maximum height are also computed. © 2010 Elsevier B.V.

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.

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.

Baglio J.,University Paris - Sud | Djouadi A.,University Paris - Sud
Journal of High Energy Physics | Year: 2011

We analyze the production of Higgs particles at the early stage of the CERN large Hadron Collider with a 7TeV center of mass energy (lHC). We first consider the case of the Standard Model Higgs boson that is mainly produced in the gluon-gluon fusion channel and to be detected in its decays into electroweak gauge bosons, gg → H → WW,ZZ, γγ. The production cross sections at √s = 7TeV and the decay branching ratios, including all relevant higher order QCD and electroweak corrections, are evaluated. An emphasis is put on the various theoretical uncertainties that affect the production rates: the significant uncertainties from scale variation and from the parametrization of the parton distribution functions as well as the uncertainties which arise due to the use of an effective field theory in the calculation of the next-to-next-to-leading order corrections. The parametric uncertainties stemming from the values of the strong coupling constant and the heavy quark masses in the Higgs decay branching ratios, which turn out to be non-negligible, are also discussed. The implications for different center of mass energies of the proton collider, √s = 8-10 TeV as well as for the design energy √s = 14TeV, are briefly summarized. We then discuss the production of the neutral Higgs particles of the Minimal Supersymmetric extension of the Standard Model in the two main channels: gluon-gluon and bottom quark fusion leading to Higgs bosons which subsequently decay into tau lepton or b-quark pairs, gg, b̄b → Higgs → + -, b̄b. The Higgs production cross sections at the lHC and the decay branching ratios are analyzed. The associated theoretical uncertainties are found to be rather large and will have a significant impact on the parameter space of the model that can be probed. © SISSA 2011.

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.

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.

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.

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.

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.

Delplace V.,University Paris - Sud | Nicolas J.,University Paris - Sud
Nature Chemistry | Year: 2015

Vinyl polymers have been the focus of intensive research over the past few decades and are attractive materials owing to their ease of synthesis and their broad diversity of architectures, compositions and functionalities. Their carbon-carbon backbones are extremely resistant to degradation, however, and this property limits their uses. Degradable polymers are an important field of research in polymer science and have been used in a wide range of applications spanning from (nano)medicine to microelectronics and environmental protection. The development of synthetic strategies to enable complete or partial degradation of vinyl polymers is, therefore, of great importance because it will offer new opportunities for the application of these materials. This Review captures the most recent and promising approaches to the design of degradable vinyl polymers and discusses the potential of these materials for biomedical applications.

Mery F.,University Paris - Sud | Burns J.G.,University Paris - Sud
Evolutionary Ecology | Year: 2010

Animals adjust their behaviour in response to complex environmental conditions. This form of plasticity requires the formation of association between information and an appropriate behavioural response. Such a connection is the result of a complex interaction between evolutionary pre-programmed cue-response behaviour (innate behavioural response) and cumulated lifetime experience (learning). The evolution of learning and innate behavioural responses is likely to depend on their respective fitness costs and benefits. However, as natural selection will indirectly affect each form through global behavioural plasticity, it is critical to understand how each form interacts with the other. The inclusion of innate behavioural plasticity and learning in behaviour is likely to result in more than the mere sum of each plastic form. In this review we investigate the costs and benefits of learning and innate behavioural responses and the effect of one on the other in their evolution. We highlight the need for more explicit study of the interaction between innate behavioural response and learning in natural systems for a better understanding of behavioural plasticity. © Springer Science+Business Media B.V. 2009.

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.

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.

Bonarota M.,University Paris - Sud | Le Gouet J.-L.,University Paris - Sud | Chaneliere T.,University Paris - Sud
New Journal of Physics | Year: 2011

We experimentally demonstrate the storage of 1060 temporal modes onto a thulium-doped crystal using an atomic frequency comb (AFC). The comb covers 0.93 GHz defining the storage bandwidth. As compared to previous AFC preparation methods (pulse sequences, i.e. amplitude modulation), we only use frequency modulation to produce the desired optical pumping spectrum. To ensure an accurate spectrally selective optical pumping, the frequencymodulated laser is self-locked on the atomic comb. Our approach is general and should be applicable to a wide range of rare-earth-doped materials in the context of multimode quantum memory. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.

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.

Magniez F.,University Paris - Sud | Mathieu C.,Brown University | Nayak A.,Perimeter Institute
Proceedings of the Annual ACM Symposium on Theory of Computing | Year: 2010

Motivated by a concrete problem and with the goal of understanding the relationship between the complexity of streaming algorithms and the computational complexity of formal languages, we investigate the problem Dyck(s) of checking matching parentheses, with s different types of parenthesis. We present a one-pass randomized streaming algorithm for Dyck(2) with space O(√ n log(n)) bits, time per letter polylog(n), and one-sided error. We prove that this one-pass algorithm is optimal, up to a log(n) factor, even when two-sided error is allowed, and conjecture that a similar bound holds for any constant number of passes over the input. Surprisingly, the space requirement shrinks drastically if we have access to the input stream "in reverse". We present a two-pass randomized streaming algorithm for Dyck(2) with space O((log n)2), time polylog(n) and one-sided error, where the second pass is in the reverse direction. Both algorithms can be extended to Dyck(s) since this problem is reducible to Dyck(2) for a suitable notion of reduction in the streaming model. Except for an extra O(√ log(s)) multiplicative overhead in the space required in the one-pass algorithm, the resource requirements are of the same order. For the lower bound, we exhibit hard instances Ascension(m) of Dyck(2) with length Θ(mn). We embed these in what we call a "one-pass" communication problem with 2m-players, where m=Õ(n). To establish the hardness of Ascension(m), we prove a direct sum result by following the "information cost" approach, but with a few twists. Indeed, we play a subtle game between public and private coins for Mountain, which corresponds to a primitive instance Ascension(1). This mixture between public and private coins for m results from a balancing act between the direct sum result and a combinatorial lower bound for Mountain. © 2010 ACM.

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.

The spin–orbit interaction couples the electrons’ motion to their spin. As a result, a charge current running through a material with strong spin–orbit coupling generates a transverse spin current (spin Hall effect, SHE) and vice versa (inverse spin Hall effect, ISHE). The emergence of SHE and ISHE as charge-to-spin interconversion mechanisms offers a variety of novel spintronic functionalities and devices, some of which do not require any ferromagnetic material. However, the interconversion efficiency of SHE and ISHE (spin Hall angle) is a bulk property that rarely exceeds ten percent, and does not take advantage of interfacial and low-dimensional effects otherwise ubiquitous in spintronic hetero- and mesostructures. Here, we make use of an interface-driven spin–orbit coupling mechanism—the Rashba effect—in the oxide two-dimensional electron system (2DES) LaAlO3/SrTiO3 to achieve spin-to-charge conversion with unprecedented efficiency. Through spin pumping, we inject a spin current from a NiFe film into the oxide 2DES and detect the resulting charge current, which can be strongly modulated by a gate voltage. We discuss the amplitude of the effect and its gate dependence on the basis of the electronic structure of the 2DES and highlight the importance of a long scattering time to achieve efficient spin-to-charge interconversion. © 2016 Nature Publishing Group

Anas S.,University Paris - Sud | Cordi A.,COrdi CONseils Sprl | Kagan H.B.,University Paris - Sud
Chemical Communications | Year: 2011

The first example of the enantioselective methyl C-H activation by an intramolecular ArPdX species and subsequent cyclisation was developed. Palladium catalysts using commercially available chiral diphosphines yield good ee's (up to 93% ee) in the synthesis of 2-methyl indolines from 2-halo N-isopropyl anilides. This approach was also employed for the synthesis of enantioenriched cyclohexyl fused indolines with moderate enantioselectivities. © 2011 The Royal Society of Chemistry.

Rio E.,University Paris - Sud | Biance A.-L.,University Claude Bernard Lyon 1
ChemPhysChem | Year: 2014

Recent advances in the coalescence in liquid foams are reviewed, with a special focus on the multiscale structure of foams. Studies concerning the stability of isolated foam films, on the one hand, and the coalescence process in macroscopic foams, on the other hand, are not always in good agreement. This discrepancy reveals that two routes can induce coalescence in a foam. The first route is thermodynamic and shows that coalescence is governed by a stochastic rupture of foam films. The second route relies on a mechanically induced rupture of the films, due to the spontaneous evolution of foams. From a literature review, the evaluation of the different timescales involved in these mechanisms allows defining the limiting parameters of foam coalescence. © 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Kociak M.,University Paris - Sud | Stephan O.,University Paris - Sud
Chemical Society Reviews | Year: 2014

In this tutorial review, we present the use of electron energy loss spectroscopy (EELS) and cathodoluminescence (CL) spectroscopy for surface plasmon mapping within metallic nanoparticles. We put a special emphasis on particles that are much smaller than the wavelength of visible light. We start by introducing the concept of surface plasmons, keeping the formalism as simple as possible by focusing on the quasi-static approximation. We then make a link between optical cross-sections, EELS and CL probabilities, and the surface plasmons' physical properties. A short survey of simulation tools is given. We then present typical experimental set-ups and describe some problems frequently encountered with spectrometers. Experimental conditions for improved signal to noise ratio are discussed. Analysis techniques are discussed, especially those related to the spectral imaging mode, which is extremely useful in EELS and CL experiments. Finally, the specific range of applications of EELS and CL with respect to other nano-optic techniques is discussed, as well as the strengths and weaknesses of EELS as compared with CL. © 2014 the Partner Organisations.

Sladkov V.,French National Center for Scientific Research | Sladkov V.,University Paris - Sud
Journal of Chromatography A | Year: 2012

The influence of non-thermostated capillary inlet on accuracy of data obtained by affinity capillary electrophoresis is examined in the case of kinetically labile systems (with fast kinetics of equilibrium) at different temperatures. The system uranyl-selenate is studied in aqueous perchloric acid solutions (pH 2.5, ionic strength 0.05moll-1) in the temperature range from 15°C to 55°C. Moving of the sample through the non-thermostated inlet into the thermostated region of the capillary is used in order to avoid the influence of non efficiently thermostated short capillary inlet. The data on mobility values of uranyl and the values of stability constants obtained by this mode are compared with the data obtained in a traditionally used mode (injection in non-thermostated inlet region). The uranyl mobility values obtained by the two methods are different at temperature higher than 35°C. However, the difference between stability constants obtained by the two methods is not significant (ambient temperature is 20°C). © 2012 Elsevier B.V.

Basset J.,University Paris - Sud | Bouchiat H.,University Paris - Sud | Deblock R.,University Paris - Sud
Physical Review Letters | Year: 2010

Using a quantum detector, a superconductor-insulator-superconductor junction, we probe separately the emission and absorption noise in the quantum regime of a superconducting resonant circuit at equilibrium. At low temperature the resonant circuit exhibits only absorption noise related to zero point fluctuations, whereas at higher temperature emission noise is also present. By coupling a Josephson junction, biased above the superconducting gap, to the same resonant circuit, we directly measure the noise power of quasiparticles tunneling through the junction at two resonance frequencies. It exhibits a strong frequency dependence, consistent with theoretical predictions. © 2010 The American Physical Society.

Greffet J.-J.,University Paris - Sud | Laroche M.,University Paris - Sud | Marquier F.,University Paris - Sud
Physical Review Letters | Year: 2010

Antennas are widely used by electrical engineers to enhance the coupling between propagating waves and electric sources or detectors. It is thus tempting to develop an optical analog to tailor visible light emission or absorption by an atom or a molecule. This idea has been put forward recently and it has been demonstrated that both the radiative rate and the emission pattern of optical emitters can be modified by metallic nanostructures. In this Letter, we introduce the concept of impedance for a nanoantenna and for two-level systems or nanoparticles described by electric dipole moments. We show how these concepts can be used to reconcile different descriptions and also to optimize nanoantennas. © 2010 The American Physical Society.

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.

Brazovskii S.,University Paris - Sud | Kirova N.,University Paris - Sud
Chemical Society Reviews | Year: 2010

In this tutorial review, we cover the solid state physics approach to electronic and optical properties of conducting polymers. We attempt to bring together languages and advantages of the solid state theory for polymers and of the quantum chemistry for monomers. We consider polymers as generic one-dimensional semiconductors with features of strongly correlated electronic systems. Our model combines the long range electron-hole Coulomb attraction with a specific effect of strong intra-monomer electronic correlations, which results in effective intra-monomer electron-hole repulsion. Our approach allows to go beyond the single-chain picture and to compare excitons for polymers in solutions and in films. The approach helps connecting such different questions as shallow singlet and deep triplet excitons, stronger binding of interchain excitons in films, crossings of excitons' branches, 1/N energies shifts in oligomers. We describe a strong suppression of the luminescence from free charge carriers by long-range Coulomb interactions. Main attention is devoted to the most requested in applications phenyl based polymers. The specifics of the benzene ring monomer give rise to existence of three possible types of excitons: Wannier-Mott, Frenkel and intermediate ones. We discuss experimental manifestations of various excitons and of their transformations. We touch effects of the time-resolved self-trapping by libron modes leading to formation of torsion polarons. © 2010 The Royal Society of Chemistry.

Nadal C.,University Paris - Sud | Majumdar S.N.,University Paris - Sud | Vergassola M.,Institute Pasteur Paris
Physical Review Letters | Year: 2010

Using a Coulomb gas method, we compute analytically the probability distribution of the Renyi entropies (a standard measure of entanglement) for a random pure state of a large bipartite quantum system. We show that, for any order q>1 of the Renyi entropy, there are two critical values at which the entropy's probability distribution changes shape. These critical points correspond to two different transitions in the corresponding charge density of the Coulomb gas: the disappearance of an integrable singularity at the origin and the detachment of a single-charge drop from the continuum sea of all the other charges. These transitions, respectively, control the left and right tails of the entropy's probability distribution, as verified also by Monte Carlo numerical simulations of the Coulomb gas equilibrium dynamics. © 2010 The American Physical Society.

Majumdar S.N.,University Paris - Sud | Rosso A.,University Paris - Sud | Zoia A.,CEA Saclay Nuclear Research Center
Physical Review Letters | Year: 2010

We present the universal features of the hitting probability Q(x,L), the probability that a generic stochastic process starting at x and evolving in a box [0, L] hits the upper boundary L before hitting the lower boundary at 0. For a generic self-affine process, we show that Q(x,L)=Q(z=x/L) has a scaling Q(z)∼z φ as z→0, where φ=θ/H, H, and θ being the Hurst and persistence exponent of the process, respectively. This result is verified in several exact calculations, including when the process represents the position of a particle diffusing in a disordered potential. We also provide numerical support for our analytical results. © 2010 The American Physical Society.

Poirel L.,University Paris - Sud | Potron A.,University Paris - Sud | Nordmann P.,University Paris - Sud
Journal of Antimicrobial Chemotherapy | Year: 2012

OXA-48-type carbapenem-hydrolysing class D β-lactamases are increasingly reported in enterobacterial species. To date, six OXA-48-like variants have been identified, with OXA-48 being the most widespread. They differ by a few amino acid substitutions or deletions (one to five amino acids). The enzymes hydrolyse penicillins at a high level and carbapenems at a low level, sparing broad-spectrum cephalosporins, and are not susceptible to β-lactamase inhibitors. When combining permeability defects, OXA-48-like producers may exhibit a high level of resistance to carbapenems. OXA-163 is an exception, hydrolysing broad-spectrum cephalosporins but carbapenems at a very low level, and being susceptible to β-lactamase inhibitors. The blaOXA-48-type genes are always plasmid-borne and have been identified in association with insertion sequences involved in their acquisition and expression. The current spread of the bla OXA-48 gene is mostly linked to the dissemination of a single IncL/M-type self-transferable plasmid of 62 kb that does not carry any additional resistance gene. OXA-48-type carbapenemases have been identified mainly from North African countries, the Middle East, Turkey and India, those areas constituting the most important reservoirs; however, occurrence of OXA-48 producers in European countries is now well documented, with some reported hospital outbreaks. Since many OXA-48-like producers do not exhibit resistance to broad-spectrum cephalosporins, or only decreased susceptibility to carbapenems, their recognition and detection can be challenging. Adequate screening and detection methods are therefore required to prevent and control their dissemination. © The Author 2012. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved.

Kumar R.R.,University Paris - Sud | Kagana H.B.,University Paris - Sud
Advanced Synthesis and Catalysis | Year: 2010

A racemic mixture may be partially transformed in the presence of a chiral catalyst by kinetic resolution and formation of products with new structural features. If the starting material is fully consumed the products may still be enantiomerically enriched. The situation is summarized in the Introduction. A brief discussion on the regioselective transformations occurring on a racemic mixture under the influence of a chiral catalyst is presented in Section 2. Often stereo-differences occur, each enantiomer of the starting material resulting in a different product. It allows one to predict what the behaviour of some enantiopure substrates should be in presence of each of the enantiomers of a chiral catalyst. Many examples are presented in Section 3. The chiral substrates under consideration have two different reacting sites, usually of the same nature (OH, C=C, allylic positions, C-H for carbene insertion, epoxide fragment, etc.). In some cases the absolute configuration of the catalyst allows an excellent control of the regioselectivity. This approach is promising for the selective transformation of chiral molecules. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.

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.

Bour C.,University Paris - Sud | Gandon V.,University Paris - Sud
Coordination Chemistry Reviews | Year: 2014

While the coordination chemistry of gallium is very rich, only a few applications of organo-gallium compounds as catalysts for molecular transformations have been reported. Nevertheless, some studies containing both families of X-ray characterized species and their catalytic activity allow the establishment of a structure-activity and a structure-stability relationship. They show that coordination compounds of gallium enable reactions that encroach upon the territory of transition metals. The interest of using specific ligands in gallium catalysis is also becoming clear in classical Lewis acid chemistry. In this review, the physical properties of gallium complexes are analyzed and related to their ability to activate alkynes toward nucleophilic additions, peracetic acid toward olefin epoxidation, and aldehydes toward hetero Diels-Alder reactions. © 2014 Elsevier B.V.

Ioffe L.B.,Rutgers University | Ioffe L.B.,University Paris - Sud | Mezard M.,University Paris - Sud
Physical Review Letters | Year: 2010

We develop an analytical theory, based on the quantum cavity method, describing the quantum phase transitions in low-temperature, strongly disordered ferromagnets and superconductors. At variance with the usual quantum critical points, we find a phase diagram with two critical points separating three phases. When the disorder increases, the systems goes from the ordered phase to an intermediate disordered phase characterized by activated transport and then to a second disordered phase where no transport is possible. Both the ordered and disordered phases exhibit strong inhomogeneity of their basic properties typical of glassy physics. © 2010 The American Physical Society.

Drenckhan W.,University Paris - Sud | Langevin D.,University Paris - Sud
Current Opinion in Colloid and Interface Science | Year: 2010

Most major recent advances in the physics of monodisperse foams are centred around the ability to generate them with excellent control of bubble sizes down to a few micrometers thanks to the development of appropriate micro- and millifluidic techniques. As a natural consequence, monodisperse liquid and solid foams are playing an increasingly important role in fundamental research and in the development of industrial applications. In this review, we will address the different properties of monodisperse foams, comparing them to the more standard polydisperse foams. © 2010 Elsevier Ltd.

Orso G.,University Paris - Sud | Burovski E.,University Paris - Sud | Jolicoeur T.,University Paris - Sud
Physical Review Letters | Year: 2010

We investigate one dimensional attractive Fermi gases in spin-dependent optical lattices. We show that three-body bound states-"trimers"-exist as soon as the two tunneling rates are different. We calculate the binding energy and the effective mass of a single trimer. We then show numerically that for finite and commensurate densities n↑=n↓/2 an energy gap appears, implying that the gas is a one-component Luttinger liquid of trimers with suppressed superfluid correlations. The boundaries of this novel phase are given. We discuss experimental situations to test our predictions. © 2010 The American Physical Society.

Toledano D.,University Paris - Sud | Gisquet-Verrier P.,University Paris - Sud
Behavioural Brain Research | Year: 2014

The present study had two main goals. First, to investigate whether an animal model of post traumatic stress disorder (PTSD), single prolonged stress (SPS) leads to one of the main PTSD symptom: avoidance of trauma-related stimuli. Second, to investigate whether a single amphetamine injection delivered 30 days after SPS can reduce these symptoms. Olfactory and auditory cues were added to the SPS context and reactivity to these cues were tested more than one month later using an odor discrimination test, and freezing to the trauma-related tone. Other PTSD symptoms, such as anxiety (elevated plus maze) and hyperarousal (acoustic startle response), were also investigated in these rats. Some behavioural reactivity to the environmental cues was observed in rats exposed to SPS. However, a subgroup of these rats showed an exaggerated disruption in performance in 3 to 4 of the behavioral tests relative to controls, suggesting that two classes of rats, those that are susceptible and those that are resilient to SPS, can be dissociated. When rats were treated with amphetamine (1. mg/kg) injected in the SPS context 30 days after SPS, traumatized rats no longer differed from their corresponding controls and all were identified as resilient. The present data demonstrated that rats exposed to SPS can be either susceptible or resilient and a single amphetamine injection can abolish the associated symptoms. We propose that combining memory reactivation, with an amphetamine-induced positive mood, can modify the emotional valence of the initial memory, inducing long-lasting remodeling of the traumatic memory, thereby opening a novel therapeutic avenue. © 2014.

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.

Ahriche A.,Jijel University | Ahriche A.,Abdus Salam International Center For Theoretical Physics | McDonald K.L.,University of Sydney | Nasri S.,United Arab Emirates University | Toma T.,University Paris - Sud
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2015

We present a model of radiative neutrino mass that automatically contains an accidental Z2 symmetry and thus provides a stable dark matter candidate. This allows a common framework for the origin of neutrino mass and dark matter without invoking any symmetries beyond those of the Standard Model. The model can be probed by direct-detection experiments and μ→e+γ searches, and predicts a charged scalar that can appear at the TeV scale, within reach of collider experiments. © 2015.

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.

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.

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).

Bouyer P.,University Paris - Sud
Reports on Progress in Physics | Year: 2010

Fifty years ago, Philip Anderson (1958 Phys. Rev. 109 1492) predicted that the introduction of impurities or defects in a conducting material could induce a sudden transition from conductor to insulator. He suggested that electrons that would move freely inside the solid do not simply diffuse on the defects as expected for classical particles but can be completely stopped. Instead of a simple decrease in the conductivity, a total cancellation of the conductivity occurs past a certain amount of disorder. The origin of this phase transition is a fundamental quantum phenomenon, interference between the many quantum amplitudes associated with various trajectories of the electron in the disordered material. This original result is essentially based on a mathematical argument, and after fifty years there are still many open questions (Lagendijk et al 2009 Phys. Today 62 (8) 24). This article provides an overview of how ultracold atoms, when combined with complex optical potential, can provide powerful tools to answer some of them (Aspect and Inguscio 2009 Phys. Today 62 (8) 30). © 2010 IOP Publishing Ltd.

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.

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.

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.

Friot S.,University Paris - Sud
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2015

Using the Mellin-Barnes representation, we show that Ruby's solid angle formula and some of its generalizations may be expressed in a compact way in terms of the Appell F4 and Lauricella FC functions. © 2014 Elsevier B.V. All rights reserved.

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.

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.

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).

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.

Das D.,University Paris - Sud | Ellwanger U.,University Paris - Sud
Journal of High Energy Physics | Year: 2010

In the Next-to-Minimal Supersymmetric Standard Model, a bino-like LSP can be as light as a few GeV and satisfy WMAP constraints on the dark matter relic density in the presence of a light CP-odd Higgs scalar. We study upper bounds on the direct detection cross sections for such a light LSP in the mass range 2-20 GeV in the NMSSM, respecting all constraints from B-physics and LEP. The OPAL constraints on e +e - → χ 0 1χ 0 i (i > 1) play an important rôle and are discussed in some detail. The resulting upper bounds on the spin-independent and spin-dependent nucleon cross sections are ∼ 10 -42 cm 2 and ∼ 4 × 10 -40 cm 2, respectively. Hence the upper bound on the spin-independent cross section is below the DAMA and CoGeNT regions, but could be compatible with the two events observed by CDMS-II.

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.

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).

Babichev E.,University Paris - Sud | Brito R.,University of Lisbon
Classical and Quantum Gravity | Year: 2015

We review the black hole (BH) solutions of the ghost-free massive gravity theory and its bimetric extension, and outline the main results on the stability of these solutions against small perturbations. Massive (bi)-gravity accommodates exact BH solutions, analogous to those of general relativity (GR). In addition to these solutions, hairy BHs - solutions with no correspondent in GR - have been found numerically, whose existence is a natural consequence of the absence of Birkhoff's theorem in these theories. The existence of extra propagating degrees of freedom, makes the stability properties of these BHs richer and more complex than those of GR. In particular, the bi-Schwarzschild BH exhibits an unstable spherically symmetric mode, while the bi-Kerr geometry is also generically unstable, both against the spherical mode and against superradiant instabilities. If astrophysical BHs are described by these solutions, the superradiant instability of the Kerr solution imposes stringent bounds on the graviton mass. © 2015 IOP Publishing 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.

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.

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.

Hamze A.,University Paris - Sud | Brion J.-D.,University Paris - Sud | Alami M.,University Paris - Sud
Organic Letters | Year: 2012

An efficient access to 1,1-diarylethylenes of biological interest by coupling functionalized aryl Grignard reagents and 1-arylvinyl halides in the presence of FeCl 3/CuTC is described. This bimetallic system proved to be superior to the use of Fe or Cu catalyst alone. The synthetic utility of this protocol is illustrated in the field of steroid chemistry. © 2012 American Chemical Society.

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.

Sausset F.,Technion - Israel Institute of Technology | Sausset F.,University Paris - Sud | Levine D.,Technion - Israel Institute of Technology
Physical Review Letters | Year: 2011

We measure and compare three correlation lengths proposed to describe the extent of structural order in amorphous systems. In particular, the recently proposed "patch correlation length" is measured as a function of temperature and fragility and shown to be comparable with other measures. In addition, we demonstrate that the patch method also allows us to characterize the symmetries of the local order without any apriori knowledge of it. © 2011 American Physical Society.

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.

Drummond J.M.,University of Savoy | Henn J.,University of Savoy | Korchemsky G.P.,University Paris - Sud | Sokatchev E.,University Paris - Sud
Nuclear Physics B | Year: 2010

We argue that all scattering amplitudes in the maximally supersymmetric N = 4 super-Yang-Mills theory possess a new, dual superconformal symmetry which extends the previously discovered dual conformal symmetry of MHV amplitudes. To reveal this property we formulate the scattering amplitudes as functions on the appropriate dual superspace. Rewritten in this form, all tree-level MHV and next-to-MHV amplitudes exhibit manifest dual superconformal symmetry. We propose a new, compact and Lorentz covariant formula for the tree-level NMHV amplitudes for arbitrary numbers and types of external particles. The dual superconformal symmetry is broken at loop level by infrared divergences. However, we provide evidence that the dual conformal anomaly of the MHV and NMHV superamplitudes is the same and, therefore, their ratio is dual conformally invariant. We show this explicitly for the six-particle amplitudes at one loop. We conjecture that these properties hold for all, MHV and non-MHV, superamplitudes in N = 4 SYM both at weak and at strong coupling. © 2009 Elsevier B.V. All rights reserved.

Arnaiz O.,French National Center for Scientific Research | Arnaiz O.,University Paris - Sud | Sperling L.,French National Center for Scientific Research | Sperling L.,University Paris - Sud
Nucleic Acids Research | Year: 2011

ParameciumDB is a community model organism database built with the GMOD toolkit to integrate the genome and biology of the ciliate Paramecium tetraurelia. Over the last four years, post-genomic data from proteome and transcriptome studies has been incorporated along with predicted orthologs in 33 species, annotations from the community and publications from the scientific literature. Available tools include BioMart for complex queries, GBrowse2 for genome browsing, the Apollo genome editor for expert curation of gene models, a Blast server, a motif finder, and a wiki for protocols, nomenclature guidelines and other documentation. In-house tools have been developed for ontology browsing and evaluation of off-target RNAi matches. Now ready for next-generation deep sequencing data and the genomes of other Paramecium species, this open-access resource is available at http://paramecium.cgm.cnrs- gif.fr. © The Author(s) 2010.

Tcherkez G.,University Paris - Sud | Boex-Fontvieille E.,University Paris - Sud | Mahe A.,University Paris - Sud | Hodges M.,University Paris - Sud
Current Opinion in Plant Biology | Year: 2012

Leaf respiration is a major metabolic process that drives energy production and growth. Earlier works in this field were focused on the measurement of respiration rates in relation to carbohydrate content, photosynthesis, enzymatic activities or nitrogen content. Recently, several studies have shed light on the mechanisms describing the regulation of respiration in the light and in the dark and on associated metabolic flux patterns. This review will highlight advances made into characterizing respiratory fluxes and provide a discussion of metabolic respiration dynamics in relation to important biological functions. © 2011 Elsevier Ltd.

Michel F.,University Paris - Sud | Parentani R.,University Paris - Sud
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2014

We study and numerically compute the scattering coefficients of shallow water waves blocked by a stationary counterflow. When the flow is transcritical, the coefficients closely follow Hawking's prediction according to which black holes should emit a thermal spectrum. We study how the spectrum deviates from thermality when reducing the maximal flow velocity, with a particular attention to subcritical flows since these have been recently used to test Hawking's prediction. For such flows, we show that the emission spectrum is strongly suppressed, and that its Planckian character is completely lost. For low frequencies, we also show that the scattering coefficients are dominated by elastic hydrodynamical channels. Our numerical results reproduce rather well the observations made by S. Weinfurtner et al. in the Vancouver experiment. Nevertheless, we propose a new interpretation of what has been observed, as well as new experimental tests. © 2014 American Physical Society.

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.

Fang B.,University Paris - Sud | Carleo G.,University Paris - Sud | Johnson A.,University Paris - Sud | Bouchoule I.,University Paris - Sud
Physical Review Letters | Year: 2014

We measure the position- and momentum-space breathing dynamics of trapped one-dimensional Bose gases at finite temperature. The profile in real space reveals sinusoidal width oscillations whose frequency varies continuously through the quasicondensate to ideal Bose gas crossover. A comparison with theoretical models taking temperature into account is provided. In momentum space, we report the first observation of a frequency doubling in the quasicondensate regime, corresponding to a self-reflection mechanism due to the repulsive interactions. Such a mechanism is predicted for a fermionized system, and has not been observed to date. The disappearance of the frequency doubling through the crossover is mapped out experimentally, giving insights into the dynamics of the breathing evolution. © 2014 American Physical Society.

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.

Grasso M.,University Paris - Sud
Physical Review C - Nuclear Physics | Year: 2014

I investigate the magicity of the isotopes Ca52 and Ca54, which was recently confirmed by two experimental measurements, and relate it to like-particle and neutron-proton tensor effects within a mean-field description. By analyzing Ca isotopes, it is shown that the like-particle tensor contribution induces shell effects that render these nuclei more magic than would be predicted by neglecting it. In particular, such induced shell effects are stronger in the Ca52 nucleus, and the single-particle gaps are increased in both isotopes due to the tensor force. By studying N=32 and N=34 isotones, neutron-proton tensor effects may be isolated and their role analyzed. It is shown that neutron-proton tensor effects lead to increasing N=32 and N=34 gaps, when going along isotonic chains, from Fe58 to Ca52 and from Fe60 to Ca54, respectively. Mean-field calculations are perfomed by employing one Skyrme parameter set, which was introduced in a previous work by fitting the tensor parameters together with the spin-orbit strength. The signs and values of the tensor strengths are thus checked within this specific application. The obtained results indicate that the employed parameter set, even if generated with a partial adjustment of the parameters of the force, leads to the correct shell behavior and provides, in particular, a description of the magicity of Ca52 and Ca54 within a pure mean-field picture with the effective two-body Skyrme interaction. © 2014 American Physical Society.

MacCormick M.,University Paris - Sud | Audi G.,University Paris - Sud
Nuclear Physics A | Year: 2014

Isobaric multiplets can be used to provide reliable mass predictions through the Isobaric Multiplet Mass Equation (IMME). Isobaric Analogue States (IAS) for isospin multiplets from T = 1/2 to 3 have been studied within the 2012 Atomic Mass Evaluation (Ame2012). Each IAS established from published experimental reaction data has been expressed in the form of a primary reaction Q-value and, when necessary, has been recalibrated. The evaluated IAS masses are provided here along with the associated IMME coefficients. Quadratic and higher order forms of the IMME have been considered, and global trends have been extracted. Particular nuclides requiring experimental investigation have been identified and discussed. This dataset is the most precise and extensive set of evaluated IAS to date. © 2014 Elsevier B.V.

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

Ducloue B.,University Paris - Sud | Szymanowski L.,National Center for Nuclear Research | Wallon S.,University Paris - Sud | Wallon S.,University Pierre and Marie Curie
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014

We study effects related to violation of energy-momentum conservation inherent to the BFKL approach, in the particular case of Mueller-Navelet jets production. We argue, based on the comparison of the lowest order non-trivial corrections O(αs3) to the cross section with predictions of an exact calculation, that the inclusion of next-to-leading order BFKL corrections to the jet production vertex significantly reduces the importance of these effects. © 2014 The Authors.

Di Renzo M.,University Paris - Sud
IEEE Transactions on Wireless Communications | Year: 2015

In this paper, a new mathematical framework to the analysis of millimeter wave cellular networks is introduced. Its peculiarity lies in considering realistic path-loss and blockage models, which are derived from recently reported experimental data. The path-loss model accounts for different distributions of line-of-sight and non-line-of-sight propagation conditions and the blockage model includes an outage state that provides a better representation of the outage possibilities of millimeter wave communications. By modeling the locations of the base stations as points of a Poisson point process and by relying on a noise-limited approximation for typical millimeter wave network deployments, simple and exact integral as well as approximated and closed-form formulas for computing the coverage probability and the average rate are obtained. With the aid of Monte Carlo simulations, the noise-limited approximation is shown to be sufficiently accurate for typical network densities. The noise-limited approximation, however, may not be sufficiently accurate for ultra-dense network deployments and for sub-gigahertz transmission bandwidths. For these case studies, the analytical approach is generalized to take the other-cell interference into account at the cost of increasing its computational complexity. The proposed mathematical framework is applicable to cell association criteria based on the smallest path-loss and on the highest received power. It accounts for beamforming alignment errors and for multi-tier cellular network deployments. Numerical results confirm that sufficiently dense millimeter wave cellular networks are capable of outperforming micro wave cellular networks, in terms of coverage probability and average rate. © 2015 IEEE.

Ducloue B.,University Paris - Sud | Szymanowski L.,National Center for Nuclear Research | Wallon S.,University Paris - Sud | Wallon S.,University Pierre and Marie Curie
Physical Review Letters | Year: 2014

The study of the production of two forward jets with a large interval of rapidity at hadron colliders was proposed by Mueller and Navelet as a possible test of the high energy dynamics of QCD. We analyze this process within a complete next-to-leading logarithm framework, supplemented by the use of the Brodsky-Lepage-Mackenzie procedure extended to the perturbative Regge dynamics, to find the optimal renormalization scale. This leads to a very good description of the recent CMS data at LHC for the azimuthal correlations of the jets. © 2014 American Physical Society.

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.

Scamps G.,French Atomic Energy Commission | Lacroix D.,University Paris - Sud
Physical Review C - Nuclear Physics | Year: 2014

The systematic study of isoscalar (IS) and isovector (IV) giant quadrupole responses (GQRs) in normal and superfluid nuclei presented in Scamps and Lacroix [Phys. Rev. C 88, 044310 (2013)PRVCAN0556-281310.1103/PhysRevC.88.044310] is extended to the case of axially deformed and triaxial nuclei. The static and dynamical energy density functionals based on Skyrme effective interaction are used to study static properties and dynamical response functions over the whole nuclear chart. Among the 749 nuclei that are considered, 301 and 65 are respectively found to be prolate and oblate, while 54 do not present any symmetry axis. For these nuclei, the IS- and IV-GQR response functions are systematically obtained. In these nuclei, different aspects related to the interplay between deformation and collective motion are studied. We show that some aspects like the fragmentation of the response induced by deformation effects in axially symmetric and triaxial nuclei can be rather well understood using simple arguments. Besides this simplicity, more complex effects show up like the appearance of nontrivial deformation effects on the collective motion damping or the influence of hexadecapole or higher-order effects. A specific study is made on the triaxial nuclei where the absence of symmetry axis adds further complexity to the nuclear response. The relative importance of geometric deformation effects and coupling to other vibrational modes are discussed. © 2014 American Physical Society.

Federici A.,University Paris - Sud | Dubois A.,University Paris - Sud
Optics Letters | Year: 2014

Full-field optical coherence microscopy is an established optical technology based on low-coherence interference microscopy for high-resolution imaging of semitransparent samples. In this Letter, we demonstrate an extension of the technique using a visible to short-wavelength infrared camera and a halogen lamp to image in three distinct bands centered at 635, 870, and 1170 nm. Reflective microscope objectives are employed to minimize chromatic aberrations of the imaging system operating over a spectral range extending from 530 to 1700 nm. Constant 1.9-μm axial resolution (measured in air) is achieved in each of the three bands. A dynamic dispersion compensation system is set up to preserve the axial resolution when the imaging depth is varied. The images can be analyzed in the conventional RGB color channels representation to generate three-dimensional images with enhanced contrast. The capability of the system is illustrated by imaging different samples. © 2014 Optical Society of America.

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.

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.

Delen X.,University Paris - Sud | Balembois F.,University Paris - Sud | Georges P.,University Paris - Sud
Optics Letters | Year: 2014

We demonstrate that Nd:YVO4 can efficiently amplify a nanosecond laser diode in a very simple double-pass configuration. Based on longitudinal pumping with a high brightness fiber-coupled laser diode at 808 nm (60 W, 100 μm, 0.22 NA) and a low Nd-doped (0.2%) temperature controlled Nd:YVO 4 we achieved an optical gain of 62 dB with very low (<2%) parasitic laser emission and an average output power of 10 W. At 15 kHz, we observed a strong gain saturation dynamic resulting in a pulse duration reduction from 100 to 3.5 ns. This effect enhances the peak power by a factor of 18 (130 kW) with an energy of 620 μJ. © 2014 Optical Society of America.

Hilairet M.,University Paris - Sud | Marchand C.,University Paris - Sud
IEEE Transactions on Industrial Electronics | Year: 2010

This paper presents a speed control strategy for a switched reluctance machine (SRM). Two control strategies are compared to select the most appropriate control that allows the SRM to operate in wide-speed-range operation. The proposed strategy is first designed to control the speed in discontinuous conduction mode and is then extended to operate in continuous conduction mode as well. In this paper, the transition from three different operating modes is detailed, and the experimental results validate the proposed strategy. © 2006 IEEE.

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.

Lorce C.,University Paris - Sud | Lorce C.,University of Liège
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.

Gupta S.,University Paris - Sud | Majumdar S.N.,University Paris - Sud | Schehr G.,University Paris - Sud
Physical Review Letters | Year: 2014

We study one-dimensional fluctuating interfaces of length L, where the interface stochastically resets to a fixed initial profile at a constant rate r. For finite r in the limit L→∞, the system settles into a nonequilibrium stationary state with non-Gaussian interface fluctuations, which we characterize analytically for the Kardar-Parisi-Zhang and Edwards-Wilkinson universality class. Our results are corroborated by numerical simulations. We also discuss the generality of our results for a fluctuating interface in a generic universality class. © 2014 American Physical Society.

Ramola K.,University Paris - Sud | Majumdar S.N.,University Paris - Sud | Schehr G.,University Paris - Sud
Physical Review Letters | Year: 2014

We study the order statistics of one-dimensional branching Brownian motion in which particles either diffuse (with diffusion constant D), die (with rate d), or split into two particles (with rate b). At the critical point b=d, which we focus on, we show that at large time t the particles are collectively bunched together. We find indeed that there are two length scales in the system: (i) the diffusive length scale ∼Dt, which controls the collective fluctuations of the whole bunch, and (ii) the length scale of the gap between the bunched particles ∼D/b. We compute the probability distribution function P̃(gk,t|n) of the kth gap gk=xk-xk+1 between the kth and (k+1)th particles given that the system contains exactly n>k particles at time t. We show that at large t, it converges to a stationary distribution P̃(gk, t→∞|n)=p(gk|n) with an algebraic tail p(gk|n)∼8(D/b)gk-3, for gk ≫ 1, independent of k and n. We verify our predictions with Monte Carlo simulations. © 2014 American Physical Society.

Busch X.,University Paris - Sud | Parentani R.,University Paris - Sud
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2014

We study the quantum entanglement of the quasiparticle pairs emitted by analog black holes. We use a phenomenological description of the spectra in dispersive media to study the domains in parameter space where the final state is nonseparable. In stationary flows, three modes are involved in each sector of fixed frequency, and not two as in homogeneous situations. The third spectator mode acts as an environment for the pairs, and the strength of the coupling significantly reduces the quantum coherence. The nonseparability of the pairs emitted by white holes is also considered and compared with that of black holes. © 2014 American Physical Society.

Lorce C.,University Paris - Sud | Lorce C.,University of Liège
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.

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.

Martin N.,University Paris - Sud | Urban M.,University Paris - Sud
Physical Review C - Nuclear Physics | Year: 2014

We study collective excitations in a superfluid neutron gas at zero temperature within the quasiparticle random-phase approximation. The particle-hole residual interaction is obtained from a Skyrme functional, while a separable interaction is used in the pairing channel, which gives a BCS gap that is very similar to the one obtained with a realistic nucleon-nucleon interaction. In accordance with the Goldstone theorem, we find an ungapped collective mode (analogous to the Bogoliubov-Anderson mode). At low momentum, its dispersion relation is approximately linear and its slope coincides with the hydrodynamic speed of sound calculated with the Skyrme equation of state. The response functions are compared with those obtained within the Landau approximation. We also compute the contribution of the collective mode to the specific heat of the neutron gas. © 2014 American Physical Society.

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.

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.

Monaco S.,University of Rome La Sapienza | Normand-Cyrot D.,University Paris - Sud | Tiefensee F.,University Paris - Sud
IEEE Transactions on Automatic Control | Year: 2011

Two sampled-data design procedures ensuring stabilization of passive systems are described in the general framework of passivity-based control (PBC) strategies. The first one makes reference to some modified output with respect to which passivity under sampling can be preserved. The second one can be interpreted as the sampled-data equivalent to the celebrated continuous-time stabilizing and damping Lg V-controller. A simulated example illustrates the performances. © 2006 IEEE.

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.

Moller A.P.,University Paris - Sud
Journal of Evolutionary Biology | Year: 2014

Life-history trade-offs occur as a consequence of the compromise between maximization of different components such as the size and the number of clutches. Flight initiation distance (FID) potentially constitutes a general proximate factor influencing such trade-offs reflecting the risks that individuals take. Therefore, greater investment in reproduction occurs at a higher risk of death, resulting in selection for efficient flight morphology. I analysed long-term data on FID in a population of barn swallows Hirundo rustica during 1984-2013 with 2196 records of FID for 1789 individuals. FID had a repeatability of 0.62 (SE = 0.04) and a heritability of 0.48 (SE = 0.07). FID varied between individuals and sites, and it increased over time as climate ameliorated. FID showed a U-shaped relationship with age, with young and very old individuals having the longest FIDs. Barn swallows that arrived early from spring migration, started to breed early and produced many fledglings had the longest FID. Individuals with the longest tails had the longest FID, and individuals with the shortest aspect ratios and wing loadings had the longest FID. Individuals that died from predation had shorter FID than survivors. These findings are consistent with the hypothesis that FID relates directly to life history, with longer FIDs being associated with smaller levels of risk-taking. © 2014 European Society For Evolutionary Biology.

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.

Geberzahn N.,University Paris - Sud | Aubin T.,University Paris - Sud
Behavioral Ecology and Sociobiology | Year: 2014

In songbirds of the temperate zone, often only males sing and their songs serve to attract females and to deter territorial rivals. In many species, males vary certain aspects of their singing behavior when engaged in territorial interactions. Such variation may be an honest signal of the traits of the signaler, such as fighting strength, condition, or aggressive motivation, and may be used by receivers in decisions on whether to retreat or to escalate a fight. This has been studied intensively in species that sing discontinuously, in which songs are alternating with silent pauses. We studied contextual variation in the song of skylarks (Alauda arvensis), a songbird with a large vocal repertoire and a continuous and versatile singing style. We exposed subjects to simulated territorial intrusions by broadcasting conspecific song and recorded their vocal responses. We found that males sing differently if they are singing spontaneously with no other conspecific around than if they are territorially challenged. In this last case, males produced lower-frequency syllables. Furthermore, they increased the sound density of their song: they increased the proportion of sound within song. They seem to do so by singing different elements of their repertoire when singing reactively. Furthermore, they increased the consistency of mean peak frequency: they repeated syllable types with less variability when singing reactively. Such contextual variation suggests that skylarks might use low frequencies, sound density, and song consistency to indicate their competitive potential, and thus, those song features might be important for mutual assessment of competitive abilities. © 2013 The Author(s).

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.

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.

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.

Cornu J.N.,University Paris - Sud
Surgical and radiologic anatomy : SRA | Year: 2010

Nerve-sparing radical prostatectomy (NSRP) is based on anatomical considerations that are still controversial. The aim of this study is to define and describe the anatomy of the fascias surrounding the prostate in a histoembryologic model and during open and laparoscopic approaches to assess their importance in surgical practice. An anatomical dissection of three fresh cadavers was conducted to reproduce an open approach. Complementary data under laparoscopic conditions were obtained from images captured from the video feed during a laparoscopic NSRP performed via a transperitoneal approach. A histological study of one fresh 25-week human male fetus, obtained following miscarriage, was also conducted to document the embryologic development of the identified fascias. Three fascias surrounding the prostate can clearly be individualized both in histologic and clinical conditions. The endopelvic fascia (EF), the prostatic fascia (PF) and the Denonvilliers' fascia (DF) recover the prostate gland and structure the periprostatic environment. Neurovascular bundles are situated in a triangle formed by PF, EF and DF. Interfascial dissection (between EF and PF) allows nerve-sparing surgery. When performing radical prostatectomy, it is mandatory to locate EF, PF and DF precisely to respect the neurovascular bundles. Nevertheless, cancer extension and anatomic variations can lead to more extensive procedures.

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.

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.

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.

Moller A.P.,University Paris - Sud | Erritzoe J.,Taps Old Rectory
Journal of Evolutionary Biology | Year: 2014

Prey avoid being eaten by assessing the risk posed by approaching predators and responding accordingly. Such an assessment may result in prey-predator communication and signalling, which entail further monitoring of the predator by prey. An early antipredator response may provide potential prey with a selective advantage, although this benefit comes at the cost of disturbance in terms of lost foraging opportunities and increased energy expenditure. Therefore, it may pay prey to assess approaching predators and determine the likelihood of attack before fleeing. Given that many approaching potential predators are detected visually, we hypothesized that species with relatively large eyes would be able to detect an approaching predator from afar. Furthermore, we hypothesized that monitoring of predators by potential prey relies on evaluation through information processing by the brain. Therefore, species with relatively larger brains for their body size should be better able to monitor the intentions of a predator, delay flight for longer and hence have shorter flight initiation distances than species with smaller brains. Indeed, flight initiation distances increased with relative eye size and decreased with relative brain size in a comparative study of 107 species of birds. In addition, flight initiation distance increased independently with size of the cerebellum, which plays a key role in motor control. These results are consistent with cognitive monitoring as an antipredator behaviour that does not result in the fastest possible, but rather the least expensive escape flights. Therefore, antipredator behaviour may have coevolved with the size of sense organs, brains and compartments of the brain involved in responses to risk of predation. © 2013 European Society For Evolutionary Biology.

Pouget J.-P.,University Paris - Sud
Physica B: Condensed Matter | Year: 2015

We review the basic aspects of the charge density wave (CDW) and bond order wave (BOW) instabilities observed in one dimension (1D) organic conductors at either the 2kF and/or 4kF critical wave vectors. We start by recalling the main features of the coupled structural/electronic Peierls instabilities observed in donor-acceptor (D-A) charge transfer (CT) salts. Then we consider the specific case of 2:1 salts D2X where X is a monovalent anion. We show that the incipient CDW/BOW instabilities of the Bechgaard and Fabre salts are those of the parent quarter-filled CT salts TMTSF-DMTCNQ and TMTTF-DMTCNQ respectively. We also consider more specifically the influence of specific features of D2X salts such as the stack dimerization, the Fermi surface warping and the coupling to the anions. Then we discuss more generally the role of the anions in the Bechgaard and Fabre salts by pointing out the influence of polarization and charge displacement induced by the anion shift. Finally we show that some of these features are also relevant to understand the subtle interplay between structural and electronic degrees of freedom in 2D quarter-filled organic salts such as the (BEDT-TTF)2X series. © 2014 Elsevier B.V.

Davier M.,University Paris - Sud
Nuclear Physics B - Proceedings Supplements | Year: 2014

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 an energy of 3-5 GeV using the initial-state radiation (ISR) method, i.e. the measurement of the cross sections e+e- → γ hadrons 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- cross section, giving the dominant contibution, many multihadronic channels have been investigated, with some recent examples presented here. We give preliminary results for the process e+e- → K+K-(γ) using 232 fb-1 of data collected with the BABAR detector at e+e- center-of-mass energies near 10.6 GeV. The lowest-order contribution to the hadronic vacuum polarization term in the muon magnetic anomaly is obtained for this channel: aKK, LOμ = (22.95 ± 0.14(stat) ± 0.22(syst)) × 10-10, which is about a factor of three more precise than the previous world average value. © 2014 Elsevier B.V.

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.

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.

Mhamdi A.,University Paris - Sud | Noctor G.,University Paris - Sud | Baker A.,University of Leeds
Archives of Biochemistry and Biophysics | Year: 2012

While genomics and post-genomics studies have revealed that plant cell redox state is controlled by a complex genetic network, available data mean that catalase must continue to be counted among the most important of antioxidative enzymes. Plants species analyzed to date contain three catalase genes, and comparison of expression patterns and information from studies on mutants suggests that the encoded proteins have relatively specific roles in determining accumulation of H 2O 2 produced through various metabolic pathways. This review provides an update on the different catalases and discusses their established or likely physiological functions. Particular attention is paid to regulation of catalase expression and activity, intracellular trafficking of the protein from cytosol to peroxisome, and the integration of catalase function into the peroxisomal antioxidative network. We discuss how plants deficient in catalase are not only key tools to identify catalase functions, but are also generating new insight into H 2O 2 signalling in plants and the potential importance of peroxisomal and other intracellular processes in this signalling. © 2012 Elsevier Inc. All rights reserved.

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.

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.

Moal V.L.-L.,CNRS Biomolecules: Conception, Isolation, and Synthesis Laboratory | Moal V.L.-L.,Laboratory of Excellence in Research on Medication and Innovative Therapeutics | Moal V.L.-L.,University Paris - Sud | Servina A.L.,Laboratory of Excellence in Research on Medication and Innovative Therapeutics | Servina A.L.,University Paris - Sud
Microbiology and Molecular Biology Reviews | Year: 2013

Hosts are protected from attack by potentially harmful enteric microorganisms, viruses, and parasites by the polarized fully differentiated epithelial cells that make up the epithelium, providing a physical and functional barrier. Enterovirulent bacteria interact with the epithelial polarized cells lining the intestinal barrier, and some invade the cells. A better understanding of the cross talk between enterovirulent bacteria and the polarized intestinal cells has resulted in the identification of essential enterovirulent bacterial structures and virulence gene products playing pivotal roles in pathogenesis. Cultured animal cell lines and cultured human nonintestinal, undifferentiated epithelial cells have been extensively used for understanding the mechanisms by which some human enterovirulent bacteria induce intestinal disorders. Human colon carcinoma cell lines which are able to express in culture the functional and structural characteristics of mature enterocytes and goblet cells have been established, mimicking structurally and functionally an intestinal epithelial barrier. Moreover, Caco-2- derived M-like cells have been established, mimicking the bacterial capture property of M cells of Peyer's patches. This review intends to analyze the cellular and molecular mechanisms of pathogenesis of human enterovirulent bacteria observed in infected cultured human colon carcinoma enterocyte-like HT-29 subpopulations, enterocyte-like Caco-2 and clone cells, the colonic T84 cell line, HT-29 mucus-secreting cell subpopulations, and Caco-2-derived M-like cells, including cell association, cell entry, intracellular lifestyle, structural lesions at the brush border, functional lesions in enterocytes and goblet cells, functional and structural lesions at the junctional domain, and host cellular defense responses. Copyright © 2013, American Society for Microbiology. All Rights Reserved.

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.

Atas Y.Y.,University Paris - Sud | Bogomolny E.,University Paris - Sud | Giraud O.,University Paris - Sud | Roux G.,University Paris - Sud
Physical Review Letters | Year: 2013

We derive expressions for the probability distribution of the ratio of two consecutive level spacings for the classical ensembles of random matrices. This ratio distribution was recently introduced to study spectral properties of many-body problems, as, contrary to the standard level spacing distributions, it does not depend on the local density of states. Our Wigner-like surmises are shown to be very accurate when compared to numerics and exact calculations in the large matrix size limit. Quantitative improvements are found through a polynomial expansion. Examples from a quantum many-body lattice model and from zeros of the Riemann zeta function are presented. © 2013 American Physical Society.

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.

Seguin-Moreau N.,University Paris - Sud
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2013

The OMEGA microelectronics group has designed a new generation of multichannel integrated circuits, the "ROC" family, in AustrianMicroSystem (AMS) SiGe 0.35 mm technology to read out signals from various families of photodetectors. The chip named MAROC (standing for Multi Anode ReadOut Chip) has been designed to read out MultiAnode Photomultipliers (MAPMT), Photomultiplier ARray In SiGe ReadOut Chip (PARISROC) to read out Photomultipliers (PMTs) and SiPM Integrated ReadOut Chip (SPIROC) to readout Silicon PhotoMultiplier (SiPM) detectors and which was the first ASIC to do so. The three of them fulfill the stringent requirements of the future photodetectors, in particular in terms of low noise, radiation hardness, large dynamic range, high density and high speed while keeping low power thanks to the SiGe technology. These multi-channel ASICs are real System on Chip (SoC) as they provide charge, time and photon-counting information which are digitized internally. Their complexity and versatility enable innovative frontier detectors and also cover spin off of these detectors in adjacent fields such as medical or material imaging as well as smart detectors. In this presentation, the three ASIC architectures and test results will be described to give a general panorama of the "ROC" chips. © 2012 Elsevier B.V. All rights reserved.

Deligny O.,University Paris - Sud
Journal of Physics: Conference Series | Year: 2014

Searches for large-scale anisotropies in the distribution of arrival directions of cosmic rays detected above ≃ 10 PeV at the Pierre Auger Observatory are presented. Although no significant deviation from isotropy is revealed at present, some of the measurements suggest that future data will provide hints for large-scale anisotropies over a wide energy range. Those anisotropies would have amplitudes which are too small to be significantly observed within the current statistics. Assuming that the cosmic ray anisotropy is dominated by dipole and quadrupole moments in the EeV-energy range, some consequences of the present upper limits on their amplitudes are presented.

Palomo L.V.,University Paris - Sud
Journal of Physics: Conference Series | Year: 2014

ALICE, one of the four main experiments at the LHC, aims to study the Quark- Gluon-Plasma, a state of matter created in high-energy heavy-ion collisions where quarks and gluons behave as free particles, rather than conllned into hadrons. In this proceedings I discuss the measurements of charmonium production in Pb-Pb collisions at SNN = 2:76 TeV performed at forward rapidity in the dimuon decay channel.

Becirevic D.,University Paris - Sud | Tayduganov A.,University Paris - Sud
Nuclear Physics B | Year: 2013

We discuss the uncertainty related to the amount of unwanted B→K0*(Kπ)ℓ+ℓ- events in the sample of B→K*(Kπ)ℓ+ℓ- ones. Those events can increase the measured differential decay rate by up to 10% in the low q2 region, and can be a source of non-negligible uncertainty in the full angular distribution of the B→K*(Kπ)ℓ+ℓ- decay. Although the transverse asymmetries should be unaffected by the presence of the S-wave Kπ pairs, coming from the scalar K0* meson, we show that in practice, their normalization might be sensitive to those events and could entail a sizable uncertainty in transverse asymmetries around q2=2GeV2. For other q2's that error is under 10%. © 2012 Elsevier B.V.

Lavarelo A.,University Paris - Sud | Roux G.,University Paris - Sud
Physical Review Letters | Year: 2013

We study the effect of disorder on frustrated dimerized spin-1/2 chains at the Majumdar-Ghosh point. Using variational methods and density-matrix renormalization group approaches, we identify two localization mechanisms for spinons which are the deconfined fractional elementary excitations of these chains. The first one belongs to the Anderson localization class and dominates at the random Majumdar-Ghosh point. There, spinons remain gapped and localize in Lifshitz states whose localization length is analytically obtained. The other mechanism is a random confinement mechanism which induces an effective interaction between spinons and brings the chain into a gapless and partially polarized phase for arbitrarily small disorder. © 2013 American Physical Society.

Lorce C.,University Paris - Sud
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2013

We present an explicit realization of the Chen et al. approach to the proton spin decomposition in terms of Wilson lines, generalizing the light-front gauge-invariant extensions discussed recently by Hatta. Particular attention is drawn to the residual gauge freedom by further separating the pure-gauge term into contour and residual terms. We show that the kinetic orbital angular momentum operator can be expressed in terms of the Wigner operator only when the momentum variable is integrated over. Finally, we confirm from twist-2 arguments that the advanced, retarded and antisymmetric light-front canonical orbital angular momenta are the same. © 2013 Elsevier B.V.

Quay C.H.L.,University Paris - Sud | Chevallier D.,University Paris - Sud | Bena C.,University Paris - Sud | Bena C.,CEA Saclay Nuclear Research Center | And 2 more authors.
Nature Physics | Year: 2013

What happens to spin-polarized electrons when they enter a superconductor? Superconductors at equilibrium and at finite temperature contain both paired particles (of opposite spin) in the condensate phase as well as unpaired, spin-randomized quasiparticles. Injecting spin-polarized electrons into a superconductor (and removing pairs) thus creates both spin and charge imbalances1-7, which must relax when the injection stops, but not necessarily over the same time (or length) scale. These different relaxation times can be probed by creating a dynamic equilibrium between continuous injection and relaxation; this leads to constant-in-time spin and charge imbalances, which scale with their respective relaxation times and with the injection current. Whereas charge imbalances in superconductors have been studied in great detail both theoretically and experimentally, spin imbalances have not received much experimental attention despite intriguing theoretical predictions of spin-charge separation effects. Here we present evidence for an almost-chargeless spin imbalance in a mesoscopic superconductor. © 2013 Macmillan Publishers Limited. All rights reserved.

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.

Nordmann P.,University Paris - Sud | Poirel L.,University Paris - Sud
Journal of Antimicrobial Chemotherapy | Year: 2013

The spread of carbapenem-hydrolysing β-lactamases in Enterobacteriaceae is becoming a major public health issue. These β-lactamases hydrolyse almost all β-lactams, are plasmid-encoded and are easily transferable among enterobacterial species. They are found in multidrug-resistant isolates. Detection of these isolates from infected specimens first relies on careful recognition of any decreased susceptibility to carbapenems. After this, rapid biochemical identification of carbapenemase producers using the novel Carba NP test should be performed. Subsequently, molecular techniques can be used to identify carbapenemase genes if necessary (epidemiology). Detection of carriers relies on a preliminary screening step, with stools or rectal swabs being screened on selective culture media such as SUPERCARBA medium, which posseses the broadest spectrum for detecting any type of carbapenemase producer. © The Author 2012. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved.

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.

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.

Allain V.,University Paris - Sud | Bourgaux C.,University Paris - Sud | Couvreur P.,University Paris - Sud
Nucleic Acids Research | Year: 2012

This short review aims at presenting some recent illustrative examples of spontaneous nucleolipids self-assembly. High-resolution structural investigations reveal the diversity and complexity of assemblies formed by these bioinspired amphiphiles, resulting from the interplay between aggregation of the lipid chains and base-base interactions. Nucleolipids supramolecular assemblies are promising soft drug delivery systems, particularly for nucleic acids. Regarding prodrugs, squalenoylation is an innovative concept for improving efficacy and delivery of nucleosidic drugs. © 2011 The Author(s).

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.

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.

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.

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.

Gourzones C.,University Paris - Sud | Barjon C.,University Paris - Sud | Busson P.,University Paris - Sud
Seminars in Cancer Biology | Year: 2012

Like other human solid tumors, nasopharyngeal carcinoma (NPC) is a tissue and a systemic disease as much as a cell disease. Tumor cell population in NPC is highly heterogeneous. Heavy infiltration by non-malignant leucocytes results at least in part from the production of abundant inflammatory cytokines by the malignant epithelial cells. There is indirect evidence that interactions between stromal and malignant cells contribute to tumor development. Peripheral blood samples collected from NPC patients contain multiple products derived from the tumor, including cytokines, non-cytokine tumor proteins, tumor exosomes and viral nucleic acids. These products represent a potential source of biomarkers for assessment of tumor aggressiveness, indirect exploration of cellular interactions and monitoring of tumor response to therapeutic agents. Most NPC patients are immunocompetent with evidence of active humoral and cellular immune responses against EBV-antigens at the systemic level. Tumor development is facilitated by local immunosuppressive factors which are not fully understood. Local accumulation of regulatory T-cells is probably one important factor. At least two NPC tumor products are suspected to contribute to their expansion, the cytokine CCL20 and the tumor exosomes carrying galectin 9. In the future, new therapeutic modalities will probably aim at breaking immune tolerance or at blocking cellular interactions critical for tumor growth. © 2012 Elsevier Ltd.

Brenner C.,University Paris - Sud | Moulin M.,University Paris - Sud
Circulation Research | Year: 2012

Mitochondria are implicated in many important cellular functions covering the whole life cycle from mitochondrial biogenesis to cell death. Mitochondrial homeostasis is tightly regulated, and mitochondrial dysfunction is frequently associated with severe human pathologies (eg, cardiovascular diseases, cancer, and neurodegeneration). The permeability transition pore (PTP) is an unselective voltage-dependent mitochondrial channel. Despite the extensive use of electrophysiology, biochemistry, pharmacology, and genetic invalidation in mice, the molecular identity of PTP is still unknown. Nevertheless, PTP is central to mitochondrial vital functions and can play a lethal role in many pathophysiological conditions. This review recapitulates the current knowledge of the various modes of conductance of the PTP channel and discusses their implication in the physiological roles of PTP and their regulation. Based on its involvement in normal physiology and human pathology, a better understanding of this channel and its roles remains a major goal for basic scientists and clinicians. © 2012 American Heart Association, Inc.

Hamai A.,University Paris - Sud | Codogno P.,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 (autophagyrelated) 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.

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.

Zemirli N.,University Paris - Sud | Arnoult D.,University Paris - Sud
International Journal of Biochemistry and Cell Biology | Year: 2012

In the cytosol, the sensing of RNA viruses by the RIG-I-like receptors (RLRs) triggers a complex signaling cascade where the mitochondrial antiviral signaling protein (MAVS) plays a crucial role in orchestrating the innate host response through the induction of antiviral and inflammatory responses. Hence, in addition to their known roles in the metabolic processes and the control of programmed cell death, mitochondria are now emerging as a fundamental hub for innate anti-viral immunity. This review summarizes the findings related to the MAVS adapter and mitochondria in the innate immune response to RNA viruses. © 2012 Elsevier Ltd.

Fourmy D.,University Paris - Sud | Yoshizawa S.,University Paris - Sud
Wiley Interdisciplinary Reviews: RNA | Year: 2012

As more RNA molecules with important cellular functions are discovered, there is a strong need to characterize their structures, functions, and interactions. Chemical and enzymatic footprinting methods are used to map RNA secondary and tertiary structure, to monitor ligand interactions and conformational changes, and in the study of protein-RNA interactions. These methods provide data at single-nucleotide resolution that nicely complements the structural information available from X-ray diffraction, nuclear magnetic resonance spectroscopy (NMR), or cryo-electron microscopy. Footprinting methods also complement the dynamic information derived from single-molecule Förster resonance energy transfer. RNA footprinting tools have been used for decades, but we have recently seen spectacular advances, for instance, the use in combination with massive parallel sequencing techniques. Large libraries of RNA molecules (small or large in size) can now be probed in high-throughput manner when RNA footprinting methods are combined with fluorescent probe technologies and automation. In this article, after a brief historical overview, we summarize recent advances in RNA-protein footprinting methodologies that now integrate tools for massive parallel analysis. © 2012 John Wiley & Sons, Ltd.

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.

Tichit P.-H.,University Paris - Sud | Burokur S.N.,CNRS Mechanical Energy and Electromagnetism Lab | De Lustrac A.,University Paris - Sud
Optics Express | Year: 2011

Using the idea of wave manipulation via transformation optics, we propose a way to create a quasi-perfect isotropic emission from a directional one. The manipulation is enabled by composite metamaterials that correspond to a space stretching around the source. It is shown that the directive radiation of a plane source larger than the operating wavelength can be transformed into an isotropic one by modifying the electromagnetic properties of the space around it. A set of parameters allowing practical realization of the proposed device is defined. Numerical simulations using Finite Element Method (FEM) are performed to illustrate the proposed coordinate transformation. This idea, which consists in strongly reducing the apparent size of a radiating source, can find various applications in novel antenna design techniques. © 2011 Optical Society of America.

Adams D.,University Paris - Sud
Current neurology and neuroscience reports | Year: 2014

Transthyretin familial amyloid polyneuropathy (TTR-FAP) classically presents as a length dependent small fiber polyneuropathy in endemic countries like Portugal. In nonendemic countries, it may mimic a variety of chronic polyneuropathies, with several phenotypes: ataxic, upper limb onset neuropathy, or motor. In these cases, there is usually a late onset and no positive family history. TTR gene sequencing appears the most pertinent first-line test for diagnosis. Cardiac involvement of various severities is common in FAP. Liver transplantation remains the standard antiamyloid therapy with better results in Val30Met TTR-FAP of early onset. Antiamyloid medication has been developed. (1) TTR stabilizers: Tafamidis was the first drug approved in Europe in stage 1 (walking unaided) TTR-FAP to slow progression of the disease; diflunisal has been assessed in a phase 3 clinical trial; (2) TTR gene silencing is a new strategy to inhibit production of both mutant and nonmutant TTR with antisense oligonucleotides or SiRNA (2 ongoing phase 3 clinical trials).

Majumdar S.N.,University Paris - Sud | Vivo P.,University Paris - Sud
Physical Review Letters | Year: 2012

We compute analytically, for large N, the probability P(N +,N) that a N×N Wishart random matrix has N + eigenvalues exceeding a threshold Nζ, including its large deviation tails. This probability plays a benchmark role when performing the principal component analysis of a large empirical data set. We find that P(N +,N) exp [- βN2ψ ζ(N +/N)], where β is the Dyson index of the ensemble and ψ ζ(κ) is a rate function that we compute explicitly in the full range 0≤κ≤1 and for any ζ. The rate function ψ ζ(κ) displays a quadratic behavior modulated by a logarithmic singularity close to its minimum κ †(ζ). This is shown to be a consequence of a phase transition in an associated Coulomb gas problem. The variance Δ(N) of the number of relevant components is also shown to grow universally (independent of ζ) as Δ(N)∼(βπ2) -1ln N for large N. © 2012 American Physical Society.

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.

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.

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.

David A.,Soraa Inc | Benisty H.,University Paris - Sud | Weisbuch C.,University of California at Santa Barbara | Weisbuch C.,CNRS Condensed Matter Physics Laboratory
Reports on Progress in Physics | Year: 2012

Photonic crystals (PhCs) are periodically structured optical media offering the opportunity for spontaneous emission (SpE) to be strongly controlled in spatial terms (directions) or in absolute terms (rates). We discuss the application of this concept for practical light-emitting sources, summarizing the principles and actual merits of various approaches based on two- and three-dimensional PhCs. We take into consideration the numerous constraints on real-world light-emitting structures and materials. The various mechanisms through which modified photonic bands and band gaps can be used are first revisited in view of their use in light sources. We then present an in-depth discussion of planar emitters and enhanced extraction of light thanks to grating diffraction. Applications to conventional III-V semiconductors and to III-nitrides are reviewed. Comparison with random surface roughening reveals some common physical limitations. Some advanced approaches with complex structures or etched active structures are also discussed. Finally, the most promising mechanism to enhance the SpE rate, the Purcell effect, is considered. Its implementation, including through plasmonic effects, is shown to be effective only for very specific sources. We conclude by outlining the mix of physics and material parameters needed to grasp the relevant issues. © 2012 IOP Publishing Ltd.

Benisty H.,University Paris - Sud | Besbes M.,University Paris - Sud
Journal of the Optical Society of America B: Optical Physics | Year: 2012

Plasmonic inverse-rib optical waveguides, consisting of a high-index inverse rib embedded in low-index medium above a flat metallic surface, are investigated under four aspects: (i) the optimal angle ? of the rib sidewall for tight modal confinement is assessed, (ii) the effect of the geometric parameters and the wavelength on propagation losses is given, (iii) we use a 3D simulation to assess how well light from an emitting dipole is captured by such a tightly guiding structure, and (iv) we show that for two such parallel hybrid waveguiding systems, when one of them has added gain, we have a plasmonic version of the PT-symmetric waveguide arrangement, and we additionally show that complex gain is needed to restore a truly exceptional point in its propagation constant evolution. © 2012 Optical Society of America.

Urban M.,University Paris - Sud
Physical Review C - Nuclear Physics | Year: 2012

The pygmy dipole resonance in neutron-rich nuclei is studied within the framework of the Vlasov equation, which is solved numerically. The interaction used in the Thomas-Fermi ground state and in the Vlasov equation is derived from an energy functional that correctly describes the equation of state of nuclear matter and neutron matter. It is found that the pygmy resonance appears in the electric dipole response of all nuclei with strong neutron excess, the energies and transition probabilities being in reasonable agreement with experimental results. Since the Vlasov equation does not account for any shell effects, this indicates that the existence of the pygmy resonance is a generic phenomenon and does not rely on the specific shell structure. Besides the electric dipole response, the isoscalar toroidal response is calculated. The transition densities and velocity fields are discussed. A comparison of the peak positions and velocity fields suggests that the pygmy resonance can be identified with one of the low-lying modes excited by the isoscalar toroidal operator. © 2012 American Physical Society.

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.

Vassal G.,University Paris - Sud | Zwaan C.M.,Erasmus MC Sophia Childrens Hospital | Ashley D.,Deakin University | Le Deley M.C.,University Paris - Sud | And 3 more authors.
The Lancet Oncology | Year: 2013

Despite major progress in the past 40 years, 20% of children with cancer die from the disease, and 40% of survivors have late adverse effects. Innovative, safe, and effective medicines are needed. Although regulatory initiatives in the past 15 years in the USA and Europe have been introduced, new drug development for children with cancer is insufficient. Children and families face major inequity between countries in terms of access to innovative drugs in development. Hurdles and bottlenecks are well known-eg, small numbers of patients, the complexity of developing targeted agents and their biomarkers for selected patients, limitations of US and EU regulations for paediatric medicines, insufficient return on investment, and the global economic crisis facing drug companies. New drug development pathways could efficiently address the challenges with innovative methods and trial designs, investment in biology and preclinical research, new models of partnership and funding including public-private partnerships and precompetitive research consortia, improved regulatory requirements, initiatives and incentives that better address these needs, and increased collaboration between paediatric oncology cooperative groups worldwide. Increased cooperation between all stakeholders-academia, parents' organisations and advocacy groups, regulatory bodies, pharmaceutical companies, philanthropic organisations, and government-will be essential. © 2013 Elsevier Ltd.

Nordmann P.,University Paris - Sud | Poirel L.,University Paris - Sud | Mark A. T.,University of Cardiff | Timothy R. W.,University of Cardiff
Journal of Antimicrobial Chemotherapy | Year: 2011

The NDM-1 gene, first identified in Sweden in 2008 in Klebsiella pneumoniae from a patient hospitalized in New Delhi, encodes a metallo-β-lactamase that inactivates all β-lactams except aztreonam. This blaNDM-1 gene has been identified in hospital-acquired bacterial species, such as K. pneumoniae, but also in the typical community-acquired species, Escherichia coli. This gene has been identified in strains that possess other resistance mechanisms contributing to their multidrug resistance patterns. It has been recently extensively reported from the UK, India and Pakistan and, albeit to a lesser extent, from a number of other countries worldwide. In most of the cases a link with the Indian subcontinent has also been established. To stem the onslaught of NDM producers, early identification of cases of NDM-related infections and prevention of their spread by implementing screening, hygiene measures and the isolation of carriers is needed. © The Author 2011. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved.

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.

Bonne N.,University Paris - Sud | Moreau G.,University Paris - Sud
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2012

Vector-Like (VL) quarks arise in the main alternatives to the supersymmetric extensions of the Standard Model (SM). Given the experimental possibility of a 125 GeV Higgs boson with rates significantly different from the SM expectations, it is motivating to study the effects of VL quarks on the Higgs boson cross sections and branching ratios. We perform a systematic search for the minimal field contents and gauge group representations of VL quarks able to significantly improve the fit of the measured Higgs rates, and simultaneously, to satisfy the direct constraints on VL quark masses as well as the electro-weak precision tests. In particular, large enhancements can be achieved in certain diphoton channels - as pointed out by both the ATLAS and CMS Collaborations - optimizing then the Higgs rate fit. This is a consequence of the introduction of VL quarks, with high electric charges of 8/3 or -7/3, which are exchanged in the Higgs-to-diphoton loop. Interestingly, the field contents and formal Higgs couplings obtained here are similar to those of scenarios in warped/composite frameworks arising from different motivations. The various exotic-charge quarks predicted, possibly below the TeV scale, might lead to a rich phenomenology soon at the LHC. © 2012 Elsevier B.V.

Gautheron C.,University Paris - Sud | Tassan-Got L.,University Paris - Sud
Chemical Geology | Year: 2010

Knowledge of the diffusion domain is of primary importance for age interpretation in noble gas thermochronometers. We have developed a Monte Carlo method to solve the diffusion equation in three-dimensional space and have used it to examine the effect of realistic crystal geometries and anisotropy on noble gas diffusion. The method is based on the simulation of Brownian motion with a modified distribution of collision distances and with a variable mean free path. This approach drastically reduces calculation time while remaining accurate. This original approach is able to treat isotropic and anisotropic diffusion, any 3D shape, ejection and zonation. A code simulating production, ejection and diffusion from the grain to the external medium has been implemented to compute helium ages of minerals subjected to temperature histories. In parallel, another module has been developed to simulate diffusion experiments and diffusion coefficient determination for all types of He profiles in a grain (homogenous, depleted edge due to ejection, heterogeneous profile due to previous diffusion, etc). Both types of simulations are suitable for isotopic and anisotropic diffusion; we develop examples for apatite and zircon (U-Th)/He thermochronology but the method can be applied to any other noble gas thermochronometer. The Monte Carlo simulation reproduces the He age variation obtained by other calculation methods for simple geometries and for well-known thermal histories, demonstrating the viability of the tool. In the case of isotropic diffusion, we show that generally even for realistic shapes with many ridges the He age resulting from the diffusion can be well calculated by assuming a spherical shape of the same surface/volume (S/V) ratio. The only requirement for adequate representation of grains by spheres is thus accurate knowledge of their true shapes and dimensions. For anisotropic diffusion, we introduce a new concept termed "active radius", which describes the complex anisotropic diffusion process by isotropic diffusion in a sphere. In this sense, the active radius can be seen as an extension of the sphere-equivalent radius to the anisotropic case. The active radius can be computed for any geometrical shape without Monte Carlo sampling, and a separate simple code is made available for its computation. © 2010 Elsevier B.V.

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

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

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.

Kegl B.,University Paris - Sud
Journal of Machine Learning Research | Year: 2014

In (Kégl, 2014), we recently showed empirically that AdaBoost.MH is one of the best multi-class boosting algorithms when the classical one-against-all base classifiers, proposed in the seminal paper of Schapire and Singer (1999), are replaced by factorized base classifiers containing a binary classifier and a vote (or code) vector. In a slightly different setup, a similar factorization coupled with an iterative optimization of the two factors also proved to be an excellent approach (Gao and Koller, 2011). The main algorithmic advantage of our approach over the original setup of Schapire and Singer (1999) is that trees can be built in a straightforward way by using the binary classifier at inner nodes. In this open problem paper we take a step back to the basic setup of boosting generic multi-class factorized (Hamming) classifiers (so no trees), and state the classical problem of boosting-like convergence of the training error. Given a vote vector, training the classifier leads to a standard weighted binary classification problem. The main difficulty of proving the convergence is that, unlike in binary AdaBoost, the sum of the weights in this weighted binary classification problem is less than one, which means that the lower bound on the edge, coming from the weak learning condition, shrinks. To show the convergence, we need a (uniform) lower bound on the sum of the weights in this derived binary classification problem. © 2014 B. Kegl.

Van Heijenoort J.,University Paris - Sud
Microbiology and Molecular Biology Reviews | Year: 2011

The review summarizes the abundant information on the 35 identified peptidoglycan (PG) hydrolases of Escherichia coli classified into 12 distinct families, including mainly glycosidases, peptidases, and amidases. An attempt is also made to critically assess their functions in PG maturation, turnover, elongation, septation, and recycling as well as in cell autolysis. There is at least one hydrolytic activity for each bond linking PG components, and most hydrolase genes were identified. Few hydrolases appear to be individually essential. The crystal structures and reaction mechanisms of certain hydrolases having defined functions were investigated. However, our knowledge of the biochemical properties of most hydrolases still remains fragmentary, and that of their cellular functions remains elusive. Owing to redundancy, PG hydrolases far outnumber the enzymes of PG biosynthesis. The presence of the two sets of enzymes acting on the PG bonds raises the question of their functional correlations. It is difficult to understand why E. coli keeps such a large set of PG hydrolases. The subtle differences in substrate specificities between the isoenzymes of each family certainly reflect a variety of as-yet-unidentified physiological functions. Their study will be a far more difficult challenge than that of the steps of the PG biosynthesis pathway. Copyright © 2011, American Society for Microbiology. All Rights Reserved.

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.

Sticlet D.,University Paris - Sud | Bena C.,University Paris - Sud | Bena C.,CEA Saclay Nuclear Research Center | Simon P.,University Paris - Sud
Physical Review Letters | Year: 2012

We study a one-dimensional wire with strong Rashba and Dresselhaus spin-orbit coupling (SOC), which supports Majorana fermions when subject to a Zeeman magnetic field and in the proximity of a superconductor. Using both analytical and numerical techniques we calculate the electronic spin texture of the Majorana end states. We find that the spin polarization of these states depends on the relative magnitude of the Rashba and Dresselhaus SOC components. Moreover, we define and calculate a local "Majorana polarization" and "Majorana density" and argue that they can be used as order parameters to characterize the topological transition between the trivial system and the system exhibiting Majorana bound modes. We find that the local Majorana polarization is correlated to the transverse spin polarization, and we propose to test the presence of Majorana fermions in a 1D system by a spin-polarized density of states measurement. © 2012 American Physical Society.

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..

Schehr G.,University Paris - Sud | Majumdar S.N.,University Paris - Sud
Physical Review Letters | Year: 2012

We study analytically the order statistics of a time series generated by the positions of a symmetric random walk of n steps with step lengths of finite variance σ2. We show that the statistics of the gap d k,n=M k,n-M k+1,n between the kth and the (k+1)th maximum of the time series becomes stationary, i.e., independent of n as n→ ∞ and exhibits a rich, universal behavior. The mean stationary gap exhibits a universal algebraic decay for large k, ∞ d k,∞/ σ∼1/√2πk, independent of the details of the jump distribution. Moreover, the probability density (pdf) of the stationary gap exhibits scaling, Pr(d k,∞=δ)(√k/σ) P(δ√k/σ), in the regime δ∼∞d k,∞. The scaling function P(x) is universal and has an unexpected power law tail, P(x)∼x -4 for large x. For δ ∞d k,∞ the scaling breaks down and the pdf gets cut off in a nonuniversal way. Consequently, the moments of the gap exhibit an unusual multiscaling behavior. © 2012 American Physical Society.

Porquet M.-G.,University Paris - Sud | Sorlin O.,French Atomic Energy Commission
Physical Review C - Nuclear Physics | Year: 2012

The evolution of the N=50 gap is analyzed as a function of the occupation of the proton πf 5/2 and πp 3/2 orbits. It is based on experimental atomic masses, using three different methods of one- or two-neutron separation energies of ground or isomeric states. We show that the effect of correlations, which is maximized at Z=32 could be misleading with respect to the determination of the size of the shell gap, especially when using the method with two-neutron separation energies. From the methods that are the least perturbed by correlations, we estimate the N=50 spherical shell gap in 2878Ni50. Whether 78Ni would be a rigid spherical or deformed nucleus is discussed in comparison with other nuclei in which similar nucleon-nucleon forces are at play. © 2012 American Physical Society.

Tordjmann T.,University Paris - Sud
Clinics and Research in Hepatology and Gastroenterology | Year: 2011

After its discovery in Drosophila, the Hippo signalling pathway has been shown to regulate organ size in mammals as well. Based on recent studies, this kinase cascade appears in particular crucial for liver tissue homeostasis, by regulating both cellular proliferation and apoptosis. Thereby, Hippo signalling may appear as a key pathway in liver carcinogenesis. © 2011.

Meyrand R.,University Paris - Sud | Galtier S.,University Paris - Sud
Physical Review Letters | Year: 2012

Hall magnetohydrodynamics (MHD) is investigated through three-dimensional direct numerical simulations. We show that the Hall effect induces a spontaneous chiral symmetry breaking of the turbulent dynamics. The normalized magnetic polarization is introduced to separate the right- (R) and left-handed (L) fluctuations. A classical k -7 /3 spectrum is found at small scales for R magnetic fluctuations which corresponds to the electron MHD prediction. A spectrum compatible with k -11 /3 is obtained at large-scales for the L magnetic fluctuations; we call this regime the ion MHD. These results are explained heuristically by rewriting the Hall MHD equations in a succinct vortex dynamical form. Applications to solar wind turbulence are discussed. © 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.

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

We establish the critical line of the one-component Φ 4 (or Landau-Ginzburg) model on the simple cubic lattice in three dimensions. Our study is performed in the framework of the non-perturbative renormalization group in the local potential approximation. Soft as well as ultra-sharp infra-red regulators are both considered. While the latter gives poor results, the critical line given by the soft cut-off compares well with the Monte Carlo simulations data of Hasenbusch [M. Hasenbusch, J. Phys. A: Math. Gen. 32 (1999) 4851] with a relative error of, at worst, ~3{dot operator}10 -3 on published points (critical parameters) of this line. © 2012 Elsevier B.V.

Messina R.,University Paris - Sud | Antezza M.,CNRS Charles Coulomb Laboratory | Ben-Abdallah P.,University Paris - Sud
Physical Review Letters | Year: 2012

Resonant tunneling of surface polaritons across a subwavelength vacuum gap between two polar or metallic bodies at different temperatures leads to an almost monochromatic heat transfer which can exceed by several orders of magnitude the far-field upper limit predicted by Planck’s blackbody theory. However, despite its strong magnitude, this transfer is very far from the maximum theoretical limit predicted in the near field. Here we propose an amplifier for the photon heat tunneling based on a passive relay system intercalated between the two bodies, which is able to partially compensate the intrinsic exponential damping of energy transmission probability thanks to three-body interaction mechanisms. As an immediate corollary, we show that the exalted transfer observed in the near field between two media can be exported at larger separation distances using such a relay. Photon heat tunneling assisted by three-body interactions enables novel applications for thermal management at nanoscale, near-field energy conversion and infrared spectroscopy. © 2012 American Physical Society.

Zugarramurdi A.,University Paris - Sud | Borisov A.G.,University Paris - Sud
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2012

For energetic atomic beams grazingly incident at a surface along low-index directions, the fast motion of the projectile in the surface plane and the slow motion in the direction perpendicular to the surface appear nearly decoupled. Fast-atom diffraction (FAD) experiments reveal two-dimensional (2D) diffraction patterns associated with exchange of the reciprocal vector perpendicular to the low-index direction of fast motion. These results are usually interpreted within the axial-channeling approximation, where the effective 2D potential experienced by the projectile is set as an average of the 3D surface potential along the atomic strings forming the channel. In this work, using the example of grazing scattering of He atoms at a LiF(001) surface, we address theoretically the range of validity of the axial-channeling approximation. Full quantum wave-packet-propagation calculations are used to study the transition from the 2D (fast atom) to the 3D diffraction pattern characteristic for low-energy atomic and molecular projectiles scattered from surfaces. Along with exact calculations, a semianalytical perturbative treatment based on the Lippmann-Schwinger equation allows an explanation of why the diffraction processes involving the exchange of reciprocal-lattice vectors along the fast-motion direction are exponentially small in typical FAD conditions. © 2012 American Physical Society.

Margueron J.,University Paris - Sud | Khan E.,University Paris - Sud
Physical Review C - Nuclear Physics | Year: 2012

Based on a microscopic description of superfluidity in overflowing nuclear systems, it is shown that continuum coupling plays an important role in the suppression, the persistence, and the reentrance of pairing. In such systems, the structure of the drip-line nucleus determines the suppression and the persistence of superfluidity. The reentrance of pairing with increasing temperature leads to additional critical temperatures between the normal and superfluid phases. © 2012 American Physical Society.

Pous C.,University Paris - Sud | Codogno P.,University Paris - Sud | Codogno P.,French Institute of Health and Medical Research
Nature Cell Biology | Year: 2011

Under nutrient-rich conditions, the nutrient-sensitive kinase mTOR (mammalian target of rapamycin) is recruited to the surface of lysosomes where it becomes activated and can promote cell growth and inhibit autophagy. In contrast, mTOR is inhibited in nutrient-poor conditions, leading to the induction of autophagy. The intracellular positioning of lysosomes in response to nutrient availability is now shown to orchestrate mTOR activation and regulate autophagy. © 2011 Macmillan Publishers Limited. All rights reserved.

Kone-Paut I.,University Paris - Sud | Piram M.,University Paris - Sud
Autoimmunity Reviews | Year: 2012

CAPS is the prototype of an IL-1β driven auto inflammatory disorder. Features of recurrent systemic inflammation compromises patient's quality of life, and may reduce life expectancy by inducing definite organ damage. Recent treatment targeting IL-1 have shown dramatic effect on patient's clinical symptoms and quality of life. Anakinra was first used successfully in treating small series of patients with all CAPS phenotypes. Two pivotal randomized placebo-controlled studies allowed licensing of rilonacept and canakinumab as orphan drugs for CAPS patients. The use of anti-IL-1 drugs in CAPS is still relatively new, and their effect on a long term is not well known. As we can suppress the clinical symptoms of patients with CAPS, important questions remain regarding the full effect of anti-IL-1 treatment on organ involvement and their potential ability to prevent them. As important variations of treatment doses and schedules appear in reaching effectiveness, pharmacologic studies are still warranted to determine a potential diffusion of anti-IL-1 drugs in the fluids and tissues. More studies evaluating the efficacy and safety of anti-IL-1 drugs given in patients before 2. years of age are warranted, since it is believed that the earliest treatment could avoid secondary CAPS complications to develop. © 2012 Elsevier B.V.

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

In this paper, we derive the Ewald method for inverse power-law interactions in quasi-two-dimensional systems. The derivation is done by using two different analytical methods. The first uses Parry's limit that considers the Ewald methods for quasi-two-dimensional systems as a limit of the Ewald methods for tridimensional systems; the second uses Poisson-Jacobi identities for lattice sums. Taking into account the equivalence of both derivations, we obtain a new analytical Fourier transform integral involving an incomplete gamma function. Energies of the generalized restrictive primitive model of electrolytes (η-RPM) and of the generalized one-component plasma model (η-OCP) are given for the tridimensional, quasi-two-dimensional and monolayers systems. Few numerical results, using Monte Carlo simulations, for η-RPM and η-OCP monolayer systems are reported. © 2010 IOP Publishing Ltd.

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.

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.

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.

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.

Metabolic network analysis is an important step for the functional understanding of biological systems. In these networks, enzymes are made of one or more functional domains often involved in different catalytic activities. Elementary flux mode (EFM) analysis is a method of choice for the topological studies of these enzymatic networks. In this article, we propose to use an EFM approach on networks that encompass available knowledge on structure-function. We introduce a new method that allows to represent the metabolic networks as functional domain networks and provides an application of the algorithm for computing elementary flux modes to analyse them. Any EFM that can be represented using the classical representation can be represented using our functional domain network representation but the fine-grained feature of functional domain networks allows to highlight new connections in EFMs. This methodology is applied to the tricarboxylic acid cycle (TCA cycle) of Bacillus subtilis, and compared to the classical analyses. This new method of analysis of the functional domain network reveals that a specific inhibition on the second domain of the lipoamide dehydrogenase (pdhD) component of pyruvate dehydrogenase complex leads to the loss of all fluxes. Such conclusion was not predictable in the classical approach.

Monnet X.,University Paris - Sud | Teboul J.-L.,University Paris - Sud
Critical Care Clinics | Year: 2015

Although use of the classic pulmonary artery catheter has declined, several techniques have emerged to estimate cardiac output. Arterial pressure waveform analysis computes cardiac output from the arterial pressure curve. The method of estimating cardiac output for these devices depends on whether they need to be calibrated by an independent measure of cardiac output. Some newer devices have been developed to estimate cardiac output from an arterial curve obtained noninvasively with photoplethysmography, allowing a noninvasive beat-by-beat estimation of cardiac output. This article describes the different devices that perform pressure waveform analysis. © 2015 Elsevier Inc.

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.

Nocturne G.,University Paris - Sud | Mariette X.,University Paris - Sud
British Journal of Haematology | Year: 2015

Primary Sjögren Syndrome (pSS) is an autoimmune disease associated with an increased risk of lymphoma. Lymphomas complicating pSS are mostly low-grade B cell non-Hodgkin lymphomas, predominantly of marginal zone histological type. Mucosal localization is predominant, notably mucosa-associated lymphoid tissue lymphomas. Lymphomas often develop in organs where pSS is active, such as salivary glands. Germinal centre (GC)-like structures, high TNFSF13B (BAFF) and Flt3-ligand (FLT3LG) levels and genetic impairment of TNFAIP3 are new predictors of lymphoma development. These new findings allow a better understanding of the pathogenic mechanisms leading to lymphoma. We propose the following scenario: auto-immune B cells with rheumatoid factor (RF) activity are continuously stimulated by immune complexes containing antibodies against more specific auto-antigens, such as SSA/Ro, SSB/La or others. Germline abnormality of TNFAIP3 leads to a decreased control of the NF-kB pathway and thus promotes survival of B cells and oncogenic mutations especially in GC structure. Moreover, B cells are stimulated by a positive loop of activation induced by BAFF secretion. Thus, lymphomagenesis associated with pSS exemplifies the development of antigen-driven B-cell lymphoma. The control of disease activity by a well-targeted immunosuppressor is the primary objective of the management of the patient in order to repress chronic B cell stimulation. © 2014 John Wiley & Sons Ltd.

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.

Tichit P.-H.,University Paris - Sud | Burokur S.N.,University Paris - Sud | De Lustrac A.,University Paris - Sud
Optics Express | Year: 2010

Spatial coordinate transformation is a suitable tool for the design of complex electromagnetic structures. In this paper, we define three spatial coordinate transformations which show the possibility of designing a taper between two different waveguides. A parametric study is presented for the three transformations and we propose achievable values of permittivity and permeability that can be obtained with existing metamaterials. The performances of such defined structures are demonstrated by finite element numerical simulations. © 2009 Optical Society of America.

Mohammad-Djafari A.,University Paris - Sud
Eurasip Journal on Advances in Signal Processing | Year: 2012

In this review article, we propose to use the Bayesian inference approach for inverse problems in signal and image processing, where we want to infer on sparse signals or images. The sparsity may be directly on the original space or in a transformed space. Here, we consider it directly on the original space (impulsive signals). To enforce the sparsity, we consider the probabilistic models and try to give an exhaustive list of such prior models and try to classify them. These models are either heavy tailed (generalized Gaussian, symmetric Weibull, Student-t or Cauchy, elastic net, generalized hyperbolic and Dirichlet) or mixture models (mixture of Gaussians, Bernoulli-Gaussian, Bernoulli-Gamma, mixture of translated Gaussians, mixture of multinomial, etc.). Depending on the prior model selected, the Bayesian computations (optimization for the joint maximum a posteriori (MAP) estimate or MCMC or variational Bayes approximations (VBA) for posterior means (PM) or complete density estimation) may become more complex. We propose these models, discuss on different possible Bayesian estimators, drive the corresponding appropriate algorithms, and discuss on their corresponding relative complexities and performances. © 2012 Mohammad-Djafari.

Imperor-Clerc M.,University Paris - Sud
Interface Focus | Year: 2012

Three-dimensional periodic complex structures are encountered in various soft matter systems such as liquid crystals, block-copolymer phases and the related nano-structured materials. Here, we review several well-defined topologies: two-dimensional hexagonal phase, three-dimensional packing of spheres, tetrahedral close packing (tcp) bi-continuous and tri-continuous cubic phases. We illustrate how small-angle X-ray scattering experiments help us to investigate these different structures and introduce the main available structural models based on both direct and inverse methods. © 2012 The Royal Society.

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.

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.

Pouget J.-P.,University Paris - Sud
Crystals | Year: 2012

We review structural aspects of the Bechgaard and Fabre salts in relationship with their electronic, magnetic and superconducting properties. We emphasize the role of bond and charge modulations of the quarter filled organic stack in the various instabilities and ground states exhibited by these salts. A special consideration is also devoted to the influence of anions and methyl groups in these processes. In particular we point out the importance of the anions in achieving the inter-stack coupling by either direct or indirect (via the polarization of the methyl group cavities) interactions with the donors. In this framework we discuss the role of anions and methyl group disorders in the inhibition of the divergence of the high temperature bond order wave instability of the Bechgaard salts. We analyze the modulation in the magnetic ground states by considering explicitly the coupling of the magnetization with structural degrees of freedom. We consider the role of the anions and methyl groups in stabilizing the charge ordering pattern in the Fabre salts. We also discuss the spin-Peierls transition of the Fabre salts in relation with the charge ordering transition and the adiabaticity of the phonon field. We review the anion ordering transitions by considering more particularly the influence of the ordering process on the electronic structure and on the ground states which results. In this framework we show that the texture of the anion ordered structure has direct consequences on the superconducting properties of (TMTSF)2ClO4. Finally we conclude on the essential implication of the structural degrees of freedom on the generic phase diagram of the Bechgaard and Fabre salts. © 2011 by the authors; licensee MDPI, Basel, Switzerland.

Bellard C.,University Paris - Sud | Bertelsmeier C.,University Paris - Sud | Leadley P.,University Paris - Sud | Thuiller W.,CNRS Alpine Ecology Laboratory | Courchamp F.,University Paris - Sud
Ecology Letters | Year: 2012

Many studies in recent years have investigated the effects of climate change on the future of biodiversity. In this review, we first examine the different possible effects of climate change that can operate at individual, population, species, community, ecosystem and biome scales, notably showing that species can respond to climate change challenges by shifting their climatic niche along three non-exclusive axes: time (e.g. phenology), space (e.g. range) and self (e.g. physiology). Then, we present the principal specificities and caveats of the most common approaches used to estimate future biodiversity at global and sub-continental scales and we synthesise their results. Finally, we highlight several challenges for future research both in theoretical and applied realms. Overall, our review shows that current estimates are very variable, depending on the method, taxonomic group, biodiversity loss metrics, spatial scales and time periods considered. Yet, the majority of models indicate alarming consequences for biodiversity, with the worst-case scenarios leading to extinction rates that would qualify as the sixth mass extinction in the history of the earth. © 2012 Blackwell Publishing Ltd/CNRS.

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..

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

Recent ground-state-focused studies of the tensor effects in the mean-field framework are our starting point. On the basis of phenomenological arguments, we indicate regions for acceptable values of the parameters that are associated with the tensor effective forces within both the Skyrme and the Gogny models. We identify acceptable signs and values of the parameters by making an adjustment on the neutron 1f spin-orbit splitting for the nuclei 40Ca, 48Ca, and 56Ni. The first nucleus is not used to adjust the tensor parameters because it is spin-saturated, but is employed to tune the spin-orbit strength. One of the main conclusions of this work is that some existing Skyrme parametrizations containing the tensor force should not be employed because the wrong sign of the tensor parameters does not lead to the correct behavior (by comparing with the experimental results). This study also allows us to better constrain the tensor parameters in the Gogny case, where much less work is published and boundaries and signs for the parameters have not been analyzed so far. © 2013 American Physical Society.

Tizei L.H.G.,University Paris - Sud | Kociak M.,University Paris - Sud
Physical Review Letters | Year: 2013

We report on the experimental demonstration of single-photon state generation and characterization in an electron microscope. In this aim we have used low intensity relativistic (energy between 60 and 100 keV) electrons beams focused in a ca. 1 nm probe to excite diamond nanoparticles. This triggered individual neutral nitrogen-vacancy centers to emit photons which could be gathered and sent to a Hanbury Brown-Twiss intensity interferometer. The detection of a dip in the correlation function at small time delays clearly demonstrates antibunching and thus the creation of nonclassical light states. Specifically, we have also demonstrated single-photon states detection. We unveil the mechanism behind quantum states generation in an electron microscope, and show that it clearly makes cathodoluminescence the nanometer scale analog of photoluminescence. By using an extremely small electron probe size and the ability to monitor its position with subnanometer resolution, we also show the possibility of measuring the quantum character of the emitted beam with deep subwavelength resolution. © 2013 American Physical Society.

Becirevic D.,University Paris - Sud | Sanfilippo F.,University Paris - Sud
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2013

We present the results of our lattice QCD study of the gD*Dπ coupling, relevant to the D*→Dπ decay. Our computation is made on the gauge field configurations that include Nf=2 dynamical light quarks by using the twisted mass QCD action. From the results obtained at four different lattice spacings we were able to take for the first time the continuum limit of this quantity computed on the lattice. Our final value, gc=0.53(3)(3), leads to Γ(D*+→D0π+)=(50±5±6) keV, and is in good agreement with the experimental results for the width of the charged D* meson. © 2013 Published by Elsevier B.V.

Beguin L.,University Paris - Sud | Vernier A.,University Paris - Sud | Chicireanu R.,Lille University of Science and Technology | Lahaye T.,University Paris - Sud | Browaeys A.,University Paris - Sud
Physical Review Letters | Year: 2013

We report the direct measurement of the van der Waals interaction between two isolated, single Rydberg atoms separated by a controlled distance of a few micrometers. Working in a regime where the single-atom Rabi frequency for excitation to the Rydberg state is comparable to the interaction, we observe partial Rydberg blockade, whereby the time-dependent populations of the various two-atom states exhibit coherent oscillations with several frequencies. Quantitative comparison of the data with a simple model based on the optical Bloch equations allows us to extract the van der Waals energy, and observe its characteristic C6/R6 dependence. The measured C6 coefficients agree well with ab initio calculations, and we observe their dramatic increase with the principal quantum number n of the Rydberg state. © 2013 American Physical Society.

Texier C.,University Paris - Sud | Majumdar S.N.,University Paris - Sud
Physical Review Letters | Year: 2013

Using the joint distribution for proper time delays of a chaotic cavity derived by Brouwer, Frahm, and Beenakker, we obtain, in the limit of the large number of channels N, the large deviation function for the distribution of the Wigner time delay (the sum of proper times) by a Coulomb gas method. We show that the existence of a power law tail originates from narrow resonance contributions, related to a (second order) freezing transition in the Coulomb gas. © 2013 American Physical Society.

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.

Mambrini Y.,University Paris - Sud | Olive K.A.,University of Minnesota | Quevillon J.,University Paris - Sud | Zaldivar B.,Institute Fisica Teorica
Physical Review Letters | Year: 2013

We study a new mechanism for the production of dark matter in the Universe which does not rely on thermal equilibrium. Dark matter is populated from the thermal bath subsequent to inflationary reheating via a massive mediator whose mass is above the reheating scale TRH. To this end, we consider models with an extra U(1) gauge symmetry broken at some intermediate scale (Mint≃1010-1012 GeV). We show that not only does the model allow for gauge coupling unification (at a higher scale associated with grand unification) but it can provide a dark matter candidate which is a standard model singlet but charged under the extra U(1). The intermediate scale gauge boson(s) which are predicted in several E6/SO(10) constructions can be a natural mediator between dark matter and the thermal bath. We show that the dark matter abundance, while never having achieved thermal equilibrium, is fixed shortly after the reheating epoch by the relation TRH3/Mint4. As a consequence, we show that the unification of gauge couplings which determines Mint also fixes the reheating temperature, which can be as high as TRH≃ 1011 GeV. © 2013 American Physical Society.

Teperik T.V.,University Paris - Sud | Nordlander P.,Rice University | Aizpurua J.,Donostia International Physics Center | Borisov A.G.,University Paris - Sud
Physical Review Letters | Year: 2013

We present the optical response of two interacting metallic nanowires calculated for separation distances down to angstrom range. State-of-the-art local and nonlocal approaches are compared with full quantum time-dependent density functional theory calculations that give an exact account of nonlocal and tunneling effects. We find that the quantum results are equivalent to those from classical approaches when the nanoparticle separation is defined as the separation between centroids of the screening charges. This establishes a universal plasmon ruler for subnanometric distances. Such a ruler not only impacts the basis of many applications of plasmonics, but also provides a robust rule for subnanometric metrology. © 2013 American Physical Society.

Braunecker B.,Autonomous University of Madrid | Simon P.,University Paris - Sud
Physical Review Letters | Year: 2013

We study a one-dimensional interacting electronic liquid coupled to a 1D array of classical magnetic moments and to a superconductor. We show that at low energy and temperature the magnetic moments and the electrons become strongly entangled and that a magnetic spiral structure emerges. For strong enough coupling between the electrons and magnetic moments, the 1D electronic liquid is driven into a topological superconducting phase supporting Majorana fermions without any fine-tuning of external parameters. Our analysis applies at low enough temperature to a quantum wire in proximity to a superconductor when the hyperfine interaction between electrons and nuclear spins is taken into account, or to a chain of magnetic adatoms adsorbed on a superconducting surface. © 2013 American Physical Society.

Girod M.,CEA DAM Ile-de-France | Schuck P.,University Paris - Sud | Schuck P.,CNRS Physics and Models in Condensed Media Laboratory
Physical Review Letters | Year: 2013

The nuclear equation of state (EOS) is explored with the constrained Hartree-Fock-Bogoliubov approach for self-conjugate nuclei. It is found that beyond a certain low, more or less universal density, those nuclei spontaneously cluster into A/4 α particles with A the nucleon number. The energy at the threshold density increases linearly with the number of α particles as does the experimental threshold energy. Taking off the spurious c.m. energy of each α particle almost gives agreement between theory and experiment. The implications of these results with respect to α clustering and the nuclear EOS at low density are discussed. © 2013 American Physical Society.