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1. The Lyapunov exponent of products of random $2\times2$ matrices close to the identity

Author

Comtet, A., Luck, J. M., Texier, C., and Tourigny, Y.

Subjects
Mathematical Physics, Condensed Matter - Disordered Systems and Neural Networks, Condensed Matter - Statistical Mechanics
Abstract

We study products of arbitrary random real $2 \times 2$ matrices that are close to the identity matrix. Using the Iwasawa decomposition of $\text{SL}(2,{\mathbb R})$, we identify a continuum regime where the mean values and the covariances of the three Iwasawa parameters are simultaneously small. In this regime, the Lyapunov exponent of the product is shown to assume a scaling form. In the general case, the corresponding scaling function is expressed in terms of Gauss' hypergeometric function. A number of particular cases are also considered, where the scaling function of the Lyapunov exponent involves other special functions (Airy, Bessel, Whittaker, elliptic). The general solution thus obtained allows us, among other things, to recover in a unified framework many results known previously from exactly solvable models of one-dimensional disordered systems., Comment: 63 pages, 1 figure, 1 table. A couple of additions and updates

Published
2012
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2. Spectral determinants and zeta functions of Schr\'odinger operators on metric graphs

Author

Harrison, J. M., Kirsten, K., and Texier, C.

Subjects
Mathematical Physics, High Energy Physics - Theory, 34B45, 81Q10, 81Q35
Abstract

A derivation of the spectral determinant of the Schr\"odinger operator on a metric graph is presented where the local matching conditions at the vertices are of the general form classified according to the scheme of Kostrykin and Schrader. To formulate the spectral determinant we first derive the spectral zeta function of the Schr\"odinger operator using an appropriate secular equation. The result obtained for the spectral determinant is along the lines of the recent conjecture., Comment: 16 pages, 2 figures

Published
2011
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3. Thermal noise and dephasing due to electron interactions in non-trivial geometries

Author

Treiber, M., Texier, C., Yevtushenko, O. M., von Delft, J., and Lerner, I. V.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

We study Johnson-Nyquist noise in macroscopically inhomogeneous disordered metals and give a microscopic derivation of the correlation function of the scalar electric potentials in real space. Starting from the interacting Hamiltonian for electrons in a metal and the random phase approximation, we find a relation between the correlation function of the electric potentials and the density fluctuations which is valid for arbitrary geometry and dimensionality. We show that the potential fluctuations are proportional to the solution of the diffusion equation, taken at zero frequency. As an example, we consider networks of quasi-1D disordered wires and give an explicit expression for the correlation function in a ring attached via arms to absorbing leads. We use this result in order to develop a theory of dephasing by electronic noise in multiply-connected systems., Comment: 9 pages, 6 figures (version submitted to PRB)

Published
2011
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4. Geometrical dependence of decoherence by electronic interactions in a GaAs/GaAlAs square network

Author

Ferrier, M., Rowe, A. C. H., Gueron, S., Bouchiat, H., Texier, C., and Montambaux, G.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Disordered Systems and Neural Networks
Abstract

We investigate weak localization in metallic networks etched in a two dimensional electron gas between $25\:$mK and $750\:$mK when electron-electron (e-e) interaction is the dominant phase breaking mechanism. We show that, at the highest temperatures, the contributions arising from trajectories that wind around the rings and trajectories that do not are governed by two different length scales. This is achieved by analyzing separately the envelope and the oscillating part of the magnetoconductance. For $T\gtrsim0.3\:$K we find $\Lphi^\mathrm{env}\propto{T}^{-1/3}$ for the envelope, and $\Lphi^\mathrm{osc}\propto{T}^{-1/2}$ for the oscillations, in agreement with the prediction for a single ring \cite{LudMir04,TexMon05}. This is the first experimental confirmation of the geometry dependence of decoherence due to e-e interaction., Comment: LaTeX, 5 pages, 4 eps figures

Published
2007
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10. Kinetic and rheological relationships of dicyanate ester polycondensation for the resin transfer molding process

Author

Texier, C., Taha, M., Maazouz, A., and Pascault, J.P.

Subjects
Plastics -- Molding, Esters -- Research, Polymers -- Rheology, Engineering and manufacturing industries, Science and technology, Research
Abstract

Kinetic and rheological behavior of a liquid dicyanate ester catalyzed by a copper salt was studied with a view to controlling the RTM process. The kinetics are satisfactorily modeled with a simple second order model until vitrification occurs. Independent of the catalyst concentration, the relationship between glass transition temperature [T.sub.g] and conversion x was well validated, indicating that vitrification occurs well before [T.sub.g](x) reaches the curing temperature. The rheological study allowed gelation (tanΔ crossover) and vitrification times at different curing temperatures to be determined. The values of tanΔ at gel point were found to be slightly higher than those usually found. In order to carry out a simulation of the RTM process, viscosity and conversion were also linked with an empirical model., INTRODUCTION Among various composite manufacturing techniques, resin transfer molding (RTM) has been recognized as a very high potential process: it combines simplicity, low cost and the capability of fabrication of [...]

Published
1997

15. Cross-talk in host&8211;parasite associations : what do past and recent proteomics approaches tell us ?

Author

Chetouhi, C., Panek, J., Bonhomme, L., El Alaoui, H., Texier, C., Langin, T., De Bekker, C., Urbach, S., Demettre, E., Missé, Dorothée, Holzmuller, P., Hughes, D.P., Zanzoni, A., Brun, C., and Biron, D.G.

Subjects
RELATION HOTE PARASITE, BIOCHIMIE, COEVOLUTION, PROTEINE, PROTEOMIQUE, BIOLOGIE MOLECULAIRE, MECANISME DE DEFENSE, GENE, EXPRESSION DES GENES, PARASITOSE, EVOLUTION, IMMUNITE
Abstract

A cross-talk in host–parasite associations begins when a host encounters a parasite. For many host–parasite relationships, this cross-talk has been taking place for hundreds of millions of years. The co-evolution of hosts and parasites, the familiar ‘arms race’ results in fascinating adaptations. Over the years, host–parasite interactions have been studied extensively from both the host and parasitic point of view. Proteomics studies have led to new insights into host–parasite cross-talk and suggest that the molecular strategies used by parasites attacking animals and plants share many similarities. Likewise, animals and plants use several common molecular tactics to counter parasite attacks. Based on proteomics surveys undertaken since the post-genomic era, a synthesis is presented on the molecular strategies used by intra- and extracellular parasites to invade and create the needed habitat for growth inside the host, as well as strategies used by hosts to counter these parasite attacks. Pitfalls in deciphering host–parasite cross-talk are also discussed. To conclude, helpful advice is given with regard to new directions that are needed to discover the generic and specific molecular strategies used by the host against parasite invasion as well as by the parasite to invade, survive, and grow inside their hosts, and to finally discover parasitic molecular signatures associated with their development.

Published
2015

18. NH3 emissions in french straw-based pig-on-litter breeding systems

Author

Mélynda Hassouna, Paul Robin, Texier, C., Sol Agro et hydrosystème Spatialisation (SAS), Institut National de la Recherche Agronomique (INRA)-AGROCAMPUS OUEST, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), and Institut du Porc (IFIP)

Subjects
[SDV]Life Sciences [q-bio], [SDE]Environmental Sciences, [INFO]Computer Science [cs], ammonia, emission, pig, litter, breeding system, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2007

20. Estimation des rejets d'azote-phosphore-potassium-cuivre et zinc des porcs. Influence de la conduite alimentaire et du mode de logement des animaux sur la nature et la gestion des déjections produites

Author

Jean-Yves Dourmad, Amandine Creusot, Jumel, R., Argouges, A. L. D., Bertrand, M., Boléat, B., Chosson, C., Marie-Line Daumer, Jannot, P., Nathalie Lemaire, Nalin, V., Franck Paboeuf, Ramonet, Y., Paul Robin, Texier, C., Tatiana Thomas, Unité mixte de recherche veau et porc (UMR VP), Ecole Nationale Supérieure Agronomique de Rennes-Institut National de la Recherche Agronomique (INRA), Sol Agro et hydrosystème Spatialisation (SAS), AGROCAMPUS OUEST, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut National de la Recherche Agronomique (INRA), Commanditaire : Ministère de l'Agriculture de l'Alimentation de la Pêche et des Affaires Rurales (France), and Type de commanditaire ou d'auteur de la saisine : Ministères, parlements et les structures qui leur sont directement rattachées

Subjects
[SDV]Life Sciences [q-bio], [SDE]Environmental Sciences, [INFO]Computer Science [cs], CONDUITE ALIMENTAIRE, REJET
Published
2003

25. Technical and economic evaluation of a unit of pig slurry management and treatment: the La Pomarede (Castelnaudary) Groupe Occitan treatment unit (C.A.L.)

Author

Coillard, J., PRADAL, G., Texier, C., Irstea Publications, Migration, Qualité des eaux et prévention des pollutions (UR QELY), Centre national du machinisme agricole, du génie rural, des eaux et forêts (CEMAGREF), Institut Technique du Porc [Le Rheu] (ITP [Le Rheu]), Institut Technique du Porc (ITP), and irstea

Subjects
[SDE] Environmental Sciences, CEMAGREF, EPU, [SDE]Environmental Sciences, ITP, QELY
Abstract

This report presents the results of the technical and economic monitoring of the pig slurry management and treatment of the Groupe Occitan', during the set up phase and the installation in stable mode., Ce rapport présente les résultats du suivi technico-économique de l'installation de gestion et de traitement du lisier de porc du Groupe Occitan pendant la phase de mise au point et de l'installation en régime stable.

Published
1994

26. Le traitement à la ferme des lisiers de porcs exédentaires : une étude de cas, l'unité de traitement de la Coopérative Agricole Lauragaise

Author

Coillard, J., Texier, C., and Irstea Publications, Migration

Subjects
[SDE] Environmental Sciences, CEMAGREF, EPU, ITP, QELY
Abstract

Pig farms, especially the biggest ones, must more and more face problems of slurry excess, that do not permit an agronomic management that is respectful of the environment. For example, the producer of 1100 sows in La Pomarède, close to Castelnaudary in the Aude department, had a small spreading land. He had to get a slurry treatment system that allows him to manage, at an agronomic level, on this surface, the treated effluent and to export the residual under a solid form. The treatment process has two main steps: an advanced separation phase that uses floculation centrifugation, and a nitrification-denitrification type of biological treatment of the liquid fraction. This study was set up in January of 1993., Les élevages de porcs, surtout les plus grands, sont de plus en plus souvent confrontés à des problèmes d'excédents de lisier qui ne leur permettent pas une gestion agronomique respectueuse de l'environnement. Ainsi, l'élevage naisseur de 1100 truies de la CAL à la Pomarède, près de Castelnaudary dans l'Aude disposait d'un plan d'épandage réduit . Il a dû s'équiper d'un dispositif de gestion et de traitement de ses lisiers qui lui permette de gérer , à dose agronomique, sur cette surface, l'effluent traité, et exporter sous une forme solide, le résidu issu du traitement. La filière de traitement comprend 2 étapes principales : une séparation de phase poussée en tête , mettant en oeuvre une floculation centrifugation, une étape de traitement biologique de type nitrification-dénitrification de la phase liquide. Cette étude a été mise en place en janvier 1993.

Published
1994

33. Identification of a tumor-specific shared antigen derived from an Eph receptor and presented to CD4 T cells on HLA class II molecules.

Author

UCL - MD/MIGE - Département de microbiologie, d'immunologie et de génétique, UCL - MD/BICL - Département de biochimie et de biologie cellulaire, Chiari, R, Hames, G, Stroobant, Vincent, Texier, C, Maillère, B, Boon, Thierry, Coulie, Pierre, UCL - MD/MIGE - Département de microbiologie, d'immunologie et de génétique, UCL - MD/BICL - Département de biochimie et de biologie cellulaire, Chiari, R, Hames, G, Stroobant, Vincent, Texier, C, Maillère, B, Boon, Thierry, and Coulie, Pierre

Abstract

We obtained a lytic CD4 T-cell clone that recognized an antigen presented by HLA-DRB1*1101 on the tumor cells of a melanoma patient who enjoyed an unusually favorable clinical evolution. The antigen appeared to be shared between several melanoma cell lines. To identify the encoding gene, we used a new method, based on the cotransfection into human embryonal kidney cell line 293 of a cDNA library from the tumor together with a cDNA clone encoding the class II transactivator, which induces the expression of HLA class II molecules. The product of the gene coding for the antigenic peptide is EphA3, a member of the Eph family of tyrosine kinase receptors, which mediate the repulsion of neural cells by cells carrying the ligand Ephrins on their surface. EphA3 is expressed at a high level in the retina and fetal brain, at a lower level in several normal tissues, and not at all in hematopoietic cells, the only cells that constitutively express HLA class II molecules. It is overexpressed in several types of tumors, including melanoma, lung carcinoma, and sarcoma. On the basis of this pattern of expression, EphA3 may be a source of tumor-specific antigens recognized on tumor cells that express HLA class II molecules. Anti-EphA3 T cells may have participated in a tumor rejection response in the patient, because the cells of metastases collected several years later than the metastasis used to characterize the antigen had lost expression of HLA-DR or EphA3, therefore escaping recognition by these lymphocytes.

Published
2000

36. Treatment of bee venom allergic subjects with phospholipase A2 T Cell epitope peptides results in iincreased expression of mRNA encoding suppressor of cytokine signalling (SOCS) 3 and a transient increase in allergen-specific IgG/G4

Author

Tarzi, M., primary, Klunker, S., additional, Texier, C., additional, Verhoef, A., additional, Stapel, S.O., additional, Akdis, C.A., additional, Maillère, B., additional, Kay, A., additional, and Larché, M., additional

Published
2005
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44. CONSIDERATION ON CALIBRATION AND CORRECTION FACTORS OF AN Hp(10) CHAMBER FOR DIFFERENT RADIATION QUALITIES AND ANGLES OF INCIDENCE.

Author

Mikamil, S., Itié, C., and Texier, C.

Subjects
DOSIMETERS, IONIZATION chambers, CALIBRATION, RADIOACTIVITY instruments, RADIATION dosimetry, PHOTONS, GAMMA rays, PHYSICS instruments, RADIATION measurements
Abstract

This paper presents the characterisation performed at IRSN (France) of an Hp(10) chamber in terms of calibration coefficient and correction factors for the radiation qualities of ISO narrow spectrum series. The chamber response, expressed in Hp(10) using conversion coefficients hpk(10; N, α) listed in ISO 4037-3 in the energy range from 30 to 1250 keV and for angles of incidence between 0 and 70°, was found to be within ∼10%. However, for photon energies <30 keV, an overresponse of the chamber that could reach 100% was observed. Nevertheless, this overresponse was reduced to 25% using the conversion coefficients estimated at Physikalisch-Technische Bundesanstalt (PTB). This implies that the X-ray spectra produced by the IRSN X-ray units are very similar to those produced by PTB, both containing a little bit more high-energy photons than the spectra used in ISO 4037-3. The dose rate dependence of the chamber tested by gamma radiation from 60Co sources was found to be within 2% in the range of 0.3 mSv h-1 to 1 Sv h-1. The Hp(10) chamber can measure directly the conventional true value of Hp(10) after calibration by a reference laboratory, and can be used for transferring Hp(10) reference quantities from a reference laboratory. [ABSTRACT FROM AUTHOR]

Published
2007
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45. Obstetrical analgesia and anaesthesia in multiple sclerosis.

Author

Dalmas, A.-F., Texier, C., Ducloy-Bouthors, A.-S., and Krivosic-Horber, R.

Subjects
*ANALGESIA, *ANESTHESIA, *MULTIPLE sclerosis, *PREGNANCY, *ANESTHETICS
Abstract

Objectives. – The use of epidural analgesia and anaesthesia is controversial in patients with multiple sclerosis (MS) due to the potential neurotoxicity of local anaesthetics. The aim of this study was to evaluate the place and the safety of epidural obstetrical analgesia in these patients.Patients and methods. – A consecutive series of 19 patients with MS was studied over 4 years, recording the type of anaesthesia and the obstetric and neurologic observations during the pregnancy and post-partum.Results. – Ten patients had epidural analgesia. One patient had a caesarean section under epidural anaesthesia. Five patients relapsed during the post-partum period. Only one of them had an epidural for a spontaneous vaginal delivery, without any evidence of a causal relationship. Spinal anaesthesia is generally not advocated in the presence of MS due to concerns relating to the stronger local anaesthetics required and was therefore not used.Conclusion. – The results confirm that epidural analgesia is innocuous in this context. The important points are the precise evaluation of the existing neurological symptoms and the sparing of local anaesthetics thanks to the addition of opioids. [Copyright &y& Elsevier]

Published
2003
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47. On the diversity and heterogeneity of H-2<SUP>d</SUP>-restricted determinants and T cell epitopes from the major bee venom allergen

Author

Texier, C., Hervé, M., Pouvelle, S., Ménez, A., and Maillère, B.

Abstract

One of the main limitations of using synthetic peptides for immunotherapy in allergic patients is the difficulty to delineate the immunodominant T cell epitopes which are necessarily dependent on HLA molecules. We have thus addressed the question of the role of MHC II molecules in immunodominant epitopes selection in the particular case of the major bee venom allergen (API m1). To exhaustively and easily explore it, we used BALB/c mice whose H-2 haplotype is associated with high IgE and IgG responses to API m1. By means of extensive sets of synthetic peptides, we investigated the specificity of polyclonal T cells and monoclonal hybridomas from mice immunized with API m1 and delineated four immunodominant regions, restricted to either the I-Ed or the I-Ad molecule. All the peptides were also tested for their capacity to bind to immunopurified MHC II molecules. Eight determinants of high affinity were identified. They clustered into three distinct regions and were largely overlapping. They included all the immunodominant epitopes, but half of them were not capable of stimulating T cells. Strikingly, interacting surfaces with either the TCR or MHC II molecule greatly differed from one determinant to another. In one case, we observed that flanking regions exerted a particular action on T cell stimulation which prevented the fine epitope localization. Our results underline the diversity and complexity of MHC II-restricted determinants and T cell epitopes from the major bee venom allergen, even in a single haplotype. These data also participate in the development of alternative approaches to conventional immunotherapy.

Published
1999

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