Showing papers by "University of Nice Sophia Antipolis published in 1996"
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TL;DR: The theoretical framework for describing the quark-gluon plasma, an important new state of matter, has been introduced in this article, with a self-contained introduction to relativistic thermal field theory, including the path integral approach, real and imaginary time formalisms, fermion fields and gauge fields at finite temperature.
Abstract: Now in paperback, this text introduces the theoretical framework for describing the quark-gluon plasma, an important new state of matter The first part of this book is a self-contained introduction to relativistic thermal field theory Topics include the path integral approach, the real and the imaginary time formalisms, fermion fields and gauge fields at finite temperature Useful techniques such as the evaluation of frequency sums or the use of cutting rules are illustrated on various examples The second part of the book is devoted to recent developments, giving a detailed account of collective excitations (bosonic and fermionic), and showing how they give rise to energy scales which imply a reorganization of perturbation theory The relation with kinetic theory is also explained Applications to processes which occur in heavy ion collisions and in astrophysics are worked out in detail Each chapter ends with exercises and a guide to the literature
1,649 citations
TL;DR: In this paper, an isoconversional kinetic analysis has been applied to nonisothermal DSC data on the cure of an epoxynovolac resin, revealing a dependence of the activation energy (Eα) on conversion (α).
Abstract: The isoconversional kinetic analysis has been applied to nonisothermal DSC data on the cure of an epoxynovolac resin. The process reveals a dependence of the activation energy (Eα) on conversion (α). The shape of the dependence has been interpreted in the terms of the reaction mechanisms. It has been found that the model dα/dt = (k1 + αmk2)(1 − α)n used for the kinetically controlled cure gives rise to the dependence of Eα on α similar to the experimentally found one. To completely describe the diffusion-controlled cure, the effect of both T and α on the change in diffusivity has been taken into account. The equation for the specific rate constant of diffusion, kD(T,α) = Do exp(−ED/RT + Kα), has been induced. Its use allows us to obtain a model dependence of Eα on α closely matching the experimental one. A technique of predicting isothermal cure from the sole dependence of Eα on α has been considered.
398 citations
TL;DR: In this paper, the authors present an analysis of the time behavior of the S&P500 (Standard and Poors) New York stock exchange index before and after the October 1987 market crash and identify precursory patterns as well as aftershock signatures and characteristic oscillations of relaxation.
Abstract: We present an analysis of the time behavior of the S&P500 (Standard and Poors) New York stock exchange index before and after the October 1987 market crash and identify precursory patterns as well as aftershock signatures and characteristic oscillations of relaxation. Combined, they ail suggest a picture of a kind of dynamical critical point, with characteristic log- periodic signatures, similar to what has been found recently for earthquakes. These observations are confirmed on other smaller crashes, and strengthen the view of the stockmarket as an example of a self-organizing cooperative system.
396 citations
TL;DR: In this paper, the non-equilibrium behavior of concentrated colloidal dispersions is studied by Stokesian Dynamics, a general molecular-dynamics-like technique for simulating particles suspended in a viscous fluid.
Abstract: The non-equilibrium behaviour of concentrated colloidal dispersions is studied by Stokesian Dynamics, a general molecular-dynamics-like technique for simulating particles suspended in a viscous fluid. The simulations are of a suspension of monodisperse Brownian hard spheres in simple shear flow as a function of the Peclet number, Pe, which measures the relative importance of shear and Brownian forces. Three clearly defined regions of behaviour are revealed. There is first a Brownian-motion-dominated regime (Pe ≤ 1) where departures from equilibrium in structure and diffusion are small, but the suspension viscosity shear thins dramatically. When the Brownian and hydrodynamic forces balance (Pe ≈ 10), the dispersion forms a new ‘phase’ with the particles aligned in ‘strings’ along the flow direction and the strings are arranged hexagonally. This flow-induced ordering persists over a range of Pe and, while the structure and diffusivity now vary considerably, the rheology remains unchanged. Finally, there is a hydrodynamically dominated regime (Pe > 200) with a dramatic change in the long-time self-diffusivity and the rheology. Here, as the Peclet number increases the suspension shear thickens owing to the formation of large clusters. The simulation results are shown to agree well with experiment.
316 citations
TL;DR: In this article, the effect of insulin on obese gene expression was examined in cells of the 3T3-F442A preadipocyte clonal line and the results indicated that the ob gene is expressed in mature fat cells only and support the possibility that insulin is an important regulator of ob gene expression.
300 citations
TL;DR: The Ponta Grossa Dike Swarm (PGDS) as mentioned in this paper is the failed arm of a rift-rift-rift triple junction, related to the separation of South America and Africa.
247 citations
TL;DR: It is concluded that p27, by setting the level of growth factor requirement, plays a pivotal role in controlling cell cycle exit, a fundamental step in growth control.
222 citations
TL;DR: A translocation, t(17;22)(q22;q13), was identified in two cases of dermatofibrosarcoma protuberans (DP), which casts light on the development and significance in DP of ring chromosomes which consistently harbor sequences derived from chromosomes 17 and 22.
Abstract: A translocation, t(17;22)(q22;q13), was identified in two cases of dermatofibrosarcoma protuberans (DP). They bring to four the number of DP cases characterized by an identical t(17;22)(q22;q13), which can be considered as a new tumor-associated chromosome rearrangement. To date, this translocation has been found only in DP and its juvenile form, giant-cell fibroblastoma. This finding has two major consequences. First, it casts light on the development and significance in DP of ring chromosomes which consistently harbor sequences derived from chromosomes 17 and 22. Second, the identification of this new chromosome marker, and eventually of the underlying molecular rearrangement, should help to classify DP, a soft-tissue tumor of still uncertain cell origin. In addition, it could be used to differentiate DP from truly benign or malignant entities, in order that this tumor of intermediate malignancy could be adequately managed.
187 citations
TL;DR: In this article, a spectroscopic analysis of the transition strengths of Er-doped LiNbO3 was performed using the Judd-Ofelt theory, taking into account the crystal anisotropy.
153 citations
TL;DR: A large range of variations in melanin-concentrating hormone messenger RNA content between individuals was observed in food-deprived versus controls or refed rats suggesting that genetic or environmental factors may alter response in melan in-concence hormone gene activity after food deprivation.
146 citations
TL;DR: Analysis of processing products derived from the NT and MCH precursors in the brain of +/fat and fat/fat mice suggests that abnormal neuropeptide and hormone precursor processing is a general phenomenon in fat/Fat mice and supports the idea that defects in the production of neuropeptic involved in the control of feeding might lead to the development of obesity in these animals.
Abstract: Mice homozygous for the fat mutation exhibit marked hyperpro-insulinemia and develop late onset obesity. The fat mutation was recently mapped to the gene encoding carboxypeptidase E (CpE), a processing enzyme involved in trimming C-terminal paired basic residues from prohormone-derived peptides. The mutation resulted in a loss of CpE activity that correlated with aberrant proinsulin processing. Neurotensin (NT) and melanin-concentrating hormone (MCH) are two neuropeptides that, among other central effects, inhibit food intake. Here, using RIA techniques coupled to reverse phase HPLC, we analyzed the processing products derived from the NT and MCH precursors in the brain of +/fat and fat/fat mice. Compared to control hypothalamic and brain extracts, fat/fat extracts had markedly reduced levels (>80%) of NT and neuromedin N (NN), another active pro-NT-derived peptide. In contrast, they exhibited high concentrations of biologically inactive NT-KR and NN-KR (NT and NN with a C-terminal Lys-Arg extension), two...
TL;DR: Forebrain structures may be functionally briefly disconnected from the brain-stem during this short-lasting stage of paradoxical sleep, which could possibly account for the mental content of a similar sleep period in humans.
TL;DR: An Adaptive Hermite Model Estimation System (AHMES) is presented for on-line beat-to-beat estimation of the features that describe the QRS complex with the Hermite model, and an application is shown, for subsequent classification, of the AHMES in extracting theQRS features of an ECG signal with the bigeminy phenomena.
Abstract: The most characteristic wave set in ECG signals is the QRS complex. Automatic procedures to classify the QRS are very useful in the diagnosis of cardiac dysfunctions. Early detection and classification of QRS changes are important in real-time monitoring. ECG data compression is also important for storage and data transmission. An Adaptive Hermite Model Estimation System (AHMES) is presented for on-line beat-to-beat estimation of the features that describe the QRS complex with the Hermite model. The AHMES is based on the multiple-input adaptive linear combiner, using as inputs the succession of the QRS complexes and the Hermite functions, where a procedure has been incorporated to adaptively estimate a width related parameter b. The system allows an efficient real-time parameter extraction for classification and data compression. The performance of the AHMES is compared with that of direct feature estimation, studying the improvement in signal-to-noise ratio. In addition, the effect of misalignment at the QRS mark is shown to become a neglecting low-pass effect. The results allow the conditions in which the AHMES improves the direct estimate to be established. The application is shown, for subsequent classification, of the AHMES in extracting the QRS features of an ECG signal with the bigeminy phenomena. Another application is highlighted that helps wide ectopic beats detection using the width parameter b.
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TL;DR: The history of this project is given and the preliminary and then the final versions of Prolog are described, which were aimed not at producing a programm3ing language but at processing natural languages; in this case, French.
Abstract: The programming language, Prolog, was born of a project aimed not at producing a programm3ing language but at processing natural languages; in this case, French. The project gave rise to a preliminary version of Prolog at the end of 1971 and a more definitive version at the end of 1972. This article gives the history of this project and describes in detail the preliminary and then the final versions of Prolog. The authors also felt it appropriate to describe the Q-systems because it was a language that played a prominent part in Prolog's genesis.
TL;DR: The specific steady state expression of the two NHE isoforms in polarized epithelial cells in culture is investigated and it is concluded that the epithelial and more specialized NHE3 isoform is exclusively restricted to the apical side of epithelial Cells.
Abstract: Na+/H+ exchangers (NHEs) are transporters that exchange sodium and proton ions across the plasma membrane at the expense of their chemical gradient. In higher eukaryotes these transporters exist as multiple specialized isoforms. For example, NHE1, the ubiquitously expressed form is a major pH-regulating system whereas the epithelial NHE3 isoform is specialized in transepithelial Na+ transport. NHE1 and NHE3 can be very well distinguished pharmacologically with the HOE694 specific inhibitor and immunologically with specific polyclonal and monoclonal antibodies. With these molecular tools we investigated the specific steady state expression of the two NHE isoforms in polarized epithelial cells in culture. Endogenous NHE3 in OK cells or NHE3-VSVG transfected in either OK or MDCK cells showed an exclusive expression of the transporter at the apical membrane. Overexpression of NHE3 did not result in any spill over on the basal lateral side. These results obtained by functional measurement of NHE3 activity were fully consistent with its detection only at the apical side by immunofluorescence and confocal microscopy. By contrast, using the same cells, the same culture conditions and the same detection methods, we clearly detected NHE1 at both specialized membranes of four different polarized epithelial cell lines. Furthermore, biotinylation of cell surface proteins of MDCK, OK and HT-29 cells followed by immunoprecipitation of NHE1 revealed expression of the transporter at both sides of the polarized epithelial cells. Interestingly, the cell surface expression correlated well with the corresponding NHE1 activities. In addition, immunodetection by fluorescence microscopy was found to be qualitatively consistent with the above-reported results. We therefore conclude that the epithelial and more specialized NHE3 isoform is exclusively restricted to the apical side of epithelial cells. In marked contrast, both endogenous or ectopically expressed NHE1 isoform, have the capacity to be expressed in both the apical and basal lateral membranes of polarized cells in cultures.
TL;DR: Using an antisense approach, it is demonstrated that induction of cyclin D1, and therefore cdk4/6 activity associated with, is positively controlled by the p42/p44 MAP kinase cascade whereas the parallel cytokines/stress-activated p38MAP Kinase cascade is antagonistic.
Abstract: Cell cycle re-entry requires the growth factor-stimulation of at least two distinct classes of protein kinases: (i) the p42/p44 MAP kinases activated by the Ras>Raf>MKK cascade and (ii) the G1 cyclin-dependent protein kinases (CDKs). Specific inactivation of either class of kinase arrests fibroblasts in G1. Growth factors promote nuclear translocation and persistent activation of p42/p44 MAP kinases during the entire G0/G1 period. Here, we demonstrate that induction of cyclin D1, and therefore cdk4/6 activity associated with, is positively controlled by the p42/p44 MAP kinase cascade whereas the parallel cytokines/stress-activated p38MAP kinase cascade is antagonistic. Finally, using an antisense approach we demonstrate that p27Kip1 plays a key role in setting the growth factor-dependency of the GO state.
TL;DR: A P2Y1 receptor on rat brain microvascular endothelial cells can account for all of the observations, and appears to couple in different native cell types to either adenylate cyclase inhibition or to phospholipase C activation.
Abstract: 1. B10 cells, a clonal line of rat brain capillary endothelial cells, exhibit a single P2 purinoceptor, activation of which leads to increases in free intracellular calcium. In the current study the identity of this P2Y receptor was determined by its binding parameters for a range of purinoceptor ligands and by its complementary DNA (cDNA) sequence. The signal transduction mechanism activated by this receptor was also investigated. 2. The radioligand [35S]-dATP alpha S bound with high affinity (Kd = 9.8 nM) to the P2Y purinoceptor expressed on B10 cells, which was found to be extremely abundant (Bmax = 22.5 pmol mg-1 protein). The calculated Ki values of a range of P2 purinoceptor agonists which competitively displaced binding of [35S]-dATP alpha S led to the rank order of affinity: dATP alpha S (Ki 3.4 nM) > 2-chloroATP (2-ClATP) (13 nM), ATP (22 nM) > ATP gamma S (43 nM) > 2-methylthioATP (2-MeSATP) (88 nM) > ADP (368 nM) > > UTP, L-beta,gamma-methyleneATP (both > 10,000 nM). The P2 purinoceptor antagonists, Reactive blue 2 and suramin, were also able to displace binding, with Ki values of 833 and 1358 nM respectively. In contrast pyridoxal-phosphate-6-azophenyl-2',4'-disulphonic acid 4-sodium (PPADS) was able to displace only 20% of [35S]-dATP alpha S binding at a concentration of 100 microM. 3. 2-ClATP (EC50 = 0.22 microM), 2-MeSATP (0.54 microM), ADP (7.9 microM) and ATP (a partial agonist), but not UTP, inhibited the cyclic AMP formation stimulated by cholera toxin, in a manner that was prevented by pertussis toxin. The purinoceptor antagonist, PPADS, was found to be inactive at a concentration of 100 microM. 4. A P2Y receptor cDNA was derived from mRNA from B10 cells and from C6-2B, a rat glioma cell line known to possess a P2Y receptor that is coupled to the inhibition of adenylate cyclase. Sequence analysis of the entire coding region revealed that both were 100% identical to the rat P2Y1 purinoceptor cDNA. No other P2Y-type receptor mRNA could be detected in B10 cells. Exactly the same sequence was isolated from rat brain cortical astrocytes, where 2-MeSATP has been shown to increase phospholipase C activity. 5. Since the receptor responsible for the transduction shares with the aforementioned binding site significant pharmacological features, including a strong activity of 2-MeSATP (characteristic of P2Y1 receptors alone among all known P2Y purinoceptors) and an unusual insensitivity to PPADS, and since abundant mRNA is present of the P2Y1 receptor but not of any other type resembling the known P2Y receptors, it is concluded that a P2Y1 receptor on rat brain microvascular endothelial cells can account for all of the observations. This single P2Y1 receptor, therefore, appears to couple in different native cell types to either adenylate cyclase inhibition or to phospholipase C activation.
TL;DR: It is suggested that heavy metals, anoxia and heat shocks exert their effects on VEGF and HO‐1 mRNA expression through separate though potentially overlapping mechanisms, which may be both cardioprotective under hypoxic/ischemic conditions.
TL;DR: It is shown that the diffusion constant of Brownian particles trapped between two walls can be derived by an extension of the single-wall reflection technique and leads to results in excellent agreement with dynamic-light-scattering experiments from colloidal suspensions in a controlled and adjustable confined geometry.
Abstract: We show that the diffusion constant of Brownian particles trapped between two walls can be derived by an extension of the single-wall reflection technique. This implies taking into account multiple backflows and leads to results in excellent agreement with our dynamic-light-scattering experiments from colloidal suspensions in a controlled and adjustable confined geometry. \textcopyright{} 1996 The American Physical Society.
TL;DR: The efficiency of this novel approach in rapid identification of the first potent inhibitor of the mammalian zinc endopeptidase neurolysin (24-16) is demonstrated, able to discriminate between this enzyme and the related zinc endopesetidase thimet oligopePTidase ( 24-15).
TL;DR: In this article, the ion concentrations of groundwater issuing from deep wells located near the epicenter of the recent earthquake of magnitude 6:9 near Kobe, Japan, on January 17, 1995 were analyzed.
Abstract: We analyze the ion concentrations of groundwater issuing from deep wells located near the epicenter of the recent earthquake of magnitude 6:9 near Kobe, Japan, on January 17, 1995. These concentrations are well tted by log-periodic modulations around a leading power law. The exponent (real and imaginary parts) is very close to those already found for the ts of precursory seismic activity for Loma Prieta and the Aleutian Islands. This brings further support for the general hypothesis that complex critical exponents are a general phenomenon in irreversible self-organizing systems and particularly in rupture and earthquake phenomena. R esum e. | Nous analysons les fluctuations de concentrations ioniques de l'eau issue de puits profonds situ es a proximite de l' epicentre du r ecent tremblement de terre de magnitude 6:9 proche de Kobe au Japon, le 17 janvier 1995. Ces fluctuations sont bien reproduites par des modulations log-p eriodiques autour d'une loi de puissance. Les parties r eelle et imaginaire de l'exposant sont tr es proches de celles trouv ees pr ec edemment pour les tremblements de terre de Loma Prieta et des Iles Al eoutiennes. Ces r esultats renforcent l'hypoth ese que des exposants critiques complexes sont une propri et eg en erale des ph enom enes de croissance irr eversible, et en particulier des probl emes de rupture et des tremblements de terre.
TL;DR: Sea urchins with C. taxifolia diet showed marked loss of spines, long righting times and small gonosomatic ratios compared with the controls, which may result either from the action of toxic substances in the alga, and/or from a too small food intake (particularly in summer).
TL;DR: In this article, the authors used ion-microprobe (SHRIMP) U-Pb zircon and Sm-Nd whole-rock ages in the West Reguibat Rise of Mauritania to provide evidence for early Archaean relicts in the northern part of the West African Craton.
Abstract: Evidence for early Archaean relicts in the northern part of the West African Craton are provided from ion-microprobe (SHRIMP) U-Pb zircon and Sm-Nd whole-rock ages in the West Reguibat Rise of Mauritania. The U-Pb ages range between 3515 ± 15 Ma and 3422 ± 10 Ma for concordant zircons from an orthogneiss which has also been affected by a 2.7 Ga old metamorphic event. Nd model ages calculated for adjacent metasediments range between 3.9 and 3.5 Ga, suggesting that these supracrustal rocks may be derived from the erosion of a similar early Archaean crust. Zircon ages and Nd depleted-mantle model ages provide the first evidence for an early Archaean crustal growth, at least 3.5–3.6 Ga old, in the West African Craton.
TL;DR: It is demonstrated that activation of p70 S6K by ΔRaf-1:ER is mediated by a new MAPK-independent pathway that is resistant to low nanomolar concentrations of wortmannin, indicating that it does not involve membrane-bound phosphatidylinositol-trisphosphate kinase activation.
01 May 1996
TL;DR: It is proved that for every shortest path routing scheme, for any constant e, O < c < 1, and for every integer d such that 3 ~ d < En, there exists a n-node network of maximum degree d that locally requires @(n log d) bits of memory on El(n) nodes.
Abstract: In this paper, we deal with the compact routing problem on distributed networks, that is implementing routing schemes that use a minimum memory size on each node. We prove that for every shortest path routing scheme, for any constant e, O < c < 1, and for every integer d such that 3 ~ d < En, there exists a n-node network of maximum degree d that locally requires @(n log d) bits of memory on El(n) nodes. This optimal lower bound means that whatever you choose the routing scheme (interval routing, boolean routing, prefix routing, . ..). there exists a network on which one can not do better than routing tables.
TL;DR: In this article, the authors discuss the importance of geophysics in the field of geology, and propose an approach to the geology of the environment. But they do not consider the effects of the weather on the geophysical properties of the ground.
Abstract: C. COULON*, P. VIDAL, C. DUPUY, P. BAUDIN, M. POPOFF*, H. MALUSKI AND D. HERMITTE 'PETROLOGIE MAGMATIQUE, URA 1277, CEREGE, BP 80, 15545 AIX EN PROVENCE CEDEX 4, FRANCE 'CENTRE DE RECHERCHES VOLCANOLOGIQUES, URA 10, 63038 CLERMONT FERRAND CEDEX, FRANCE 'CENTRE GEOLOGIO.UE ET GEOPHYSIO.UE, CNRS, PLACE BATAILLON, J4095 MONTPELLIER CEDEX, FRANCE *INSTITUT DE GEODYNAMIQ.UE, URA 1279, UNIVERSITE DE NICE—SOPHIA ANTIPOLIS, AVENUE EINSTEIN, 06560 VALBONNE, FRANCE LABORATOIRE DE GEOCHRONOLOGIE—GEOCHIMIE, URA 176J, PLACE BATAILLON, 34095 MONTPELLIER CEDEX, FRANCE
TL;DR: In this article, the authors performed a laser probe 40Ar/39Ar and 87Rb/87Sr study on new samples from the same Mn deposit and found that minimum fractionation occurs during cryptomelane crystallization, except for the latest generation.
TL;DR: This study allows to establish some correlation between fabrication parameters and the crystalline structure, the index profiles, and the propagation losses of waveguides prepared by this process.
Abstract: By using x-ray diffraction and optical waveguide characterization, it has been shown that proton-exchanged layers on Z-cut LiNbO(3) can have as many as seven different crystallographic phases that are stable at room temperature. This study allows us to establish some correlation between fabrication parameters and the crystalline structure, the index profiles, and the propagation losses of waveguides prepared by this process.
TL;DR: In this paper, the utilization of bismuth compounds in oxidation reactions of organic derivatives was discussed and both the pentavalent and trivalent states of Bismuth were found to display oxidizing power.