Showing papers by "Centre national de la recherche scientifique published in 1981"
TL;DR: In this paper, it was shown that the Green9s functions for an elastic layered medium can be expressed as a double integral over frequency and horizontal wavenumber, which can be exactly represented by a discrete summation.
Abstract: Green9s functions for an elastic layered medium can be expressed as a double integral over frequency and horizontal wavenumber. We show that, for any time window, the wavenumber integral can be exactly represented by a discrete summation. This discretization is achieved by adding to the particular point source an infinite set of specified circular sources centered around the point source and distributed at equal radial interval. Choice of this interval is dependent on the length of time desired for the point source response and determines the discretized set of horizontal wavenumbers which contribute to the solution. Comparisons of the results obtained with those derived using the two-dimensional discretization method (Bouchon, 1979) are presented. They show the great accuracy of the two methods.
928 citations
TL;DR: The pathological alterations (signs of degeneration) were almost exclusively present in structures in which there had been a rise in metabolism (in particular the hippocampal formation, lateral septum, amygdala, medial thalamus and claustrum) and there is a remarkable correlation between the electrographic changes and the Rise in metabolism.
666 citations
TL;DR: In this article, the authors give a sufficient condition for a self-adjoint operator to have the following properties in a neighborhood of a pointE of its spectrum, where the point spectrum is finite and singular continuous spectrum is empty.
Abstract: We give a sufficient condition for a self-adjoint operator to have the following properties in a neighborhood of a pointE of its spectrum:
a)
its point spectrum is finite;
b)
its singular continuous spectrum is empty;
c)
its resolvent satisfies a class of a priori estimates.
660 citations
TL;DR: An interpretation in which the syllable is considered a processing unit in speech perception is advanced because of the results showed that reaction times to targets which correspond to the first syllable of the word were faster than those that did not, independently of the target size.
508 citations
TL;DR: In this paper, the effect of primary, linear alcohols (ethanol to hexanol) on the micellar properties (CMC, micelle ionization degree β and molecular weight M w composition of the mixed alcohol + surfactant micelles) of solutions of alkyltrimethylammonium bromides (octyl to hexadecyl) has been investigated, with particular emphasis on the system pentanol-tetradecyltrimethyllammoniam bromide (TTAB).
413 citations
TL;DR: In this paper, a new set of parameters for skyrme interactions have been determined, including the compression modulus, spin and spin-isospin Landau parameters, and pairing matrix elements.
412 citations
TL;DR: In this article, the authors defend the identification of pole with constituent masses on the one hand and of invariant mass flavour ratio with current mass flavour ratios on the other hand, and prove that the pole mass is gauge-parameter independent and infrared finite at the two-loop level.
392 citations
TL;DR: Isotopic, micropaleontologic and pollen analyses of deep-sea cores from the Bay of Biscay and the northeastern Atlantic Ocean show that the deglacial warming of this oceanic area was closely correlated with the paleoclimatic evolution of the adjacent European continent.
380 citations
TL;DR: In this article, a series of phases MICa2Nb3O10 (MI = Li, Na, K, Rb, Cs, NH4, Tl) has been prepared and characterized.
372 citations
TL;DR: In this paper, direct numerical simulations of three-dimensional magnetohydrodynamic turbulence with kinetic and magnetic Reynolds numbers up to 100 are presented, showing that small-scale helical driving produces strong large-scale nearly force-free magnetic fields.
Abstract: Direct numerical simulations of three-dimensional magnetohydrodynamic turbulence with kinetic and magnetic Reynolds numbers up to 100 are presented. Spatially intermittent magnetic fields are observed in a flow with nonhelical driving. Small-scale helical driving produces strong large-scale nearly force-free magnetic fields.
333 citations
TL;DR: Each pair of actin subunits in the thin filament seems to act as a functional unit for specific binding of a myosin head and stimulation of its Mg2+-ATPase activity.
Abstract: The topography of the rigor complex between F-actin and myosin heads (S1) has been investigated by carbodiimide zero-length cross-linking. The results demonstrate for the first time that the 95,000-molecular weight (95K) heavy chain of the myosin head enters into van der Waals contact with two neighbouring actin monomers; one is bound to the 50K domain and the other to the 20K domain of the myosin chain. The covalent F-actin-S1 complex can be isolated; it shows a vastly elevated Mg2+-ATPase. Each pair of actin subunits in the thin filament seems to act as a functional unit for specific binding of a myosin head and stimulation of its Mg2+-ATPase activity.
TL;DR: It is shown that enkephalin and catecholamines are released together from primary cultures of bovine adrenal medullary chromaffin cells by nicotine in a Ca2+-dependent manner.
Abstract: The opioid peptides Leu-enkephalin and Met-enkephalin are stored intraneuronally in the brain where they are thought to act as neurotransmitters and/or neuromodulators. Evidence for their release from nerve terminals has come from biochemical and pharmacological studies in vitro with brain tissue slices and synaptosomes. Enkephalins also exist in the peripheral nervous system in nerve cell bodies and axon terminals in the gastrointestinal tract, sympathetic ganglia and adrenal gland. In the adrenal gland, high levels of enkephalins are present both in axon terminals of the splanchnic nerve and in the adrenal medullary chromaffin cells where they are stored together with the catecholamines in the chromaffin granules. Stimulation of the adrenal gland in vivo or the perfused gland in vitro causes release of catecholamines and enkephalins into the adrenal vein. However, it is not clear whether the origin of the released enkephalins is the adrenal medullary chromaffin cells or the enkephalin-containing splanchnic nerve terminals that innervate the medulla. We now show that enkephalin and catecholamines are released together from primary cultures of bovine adrenal medullary chromaffin cells by nicotine in a Ca2+-dependent manner.
TL;DR: In this article, the authors examined the electronic excitation spectrum of a bipolaronic crystal and showed that in the low bipolaron density limit the spectrum is superfluidlike, so that bipolarons might be superconducting.
Abstract: It is shown that in narrow-band crystals with sufficiently strong electron-lattice interaction a new energy band occurs. The tunneling motion of localized electron pairs (bipolarons), which is responsible for this band, is caused by virtual transitions of bipolarons to the polaron state. The electronic excitation spectrum of a bipolaronic crystal is examined. It is shown that in the low bipolaron-density limit the excitation spectrum is superfluidlike, so that bipolarons might be superconducting. In case of high density of bipolarons and their strong repulsion, a charge-density wave is predicted.
TL;DR: The role played by shape-selective properties of the zeolites on their behavior towards coking and aging and also the effect of coking on the availability of Bronsted acidic sites have been particularly emphasized in this paper.
TL;DR: The observations of a number of objects by the Voyager EUV instruments are summarized in this article, and the summary is considered to demonstrate the wide ranging application of the EUV spectroscopy and emphasizes the continuing importance of the search and discovery nature of spectroscopic techniques.
Abstract: The observations of a number of objects by the Voyager EUV instruments are summarized. The summary is considered to demonstrate the wide ranging application of the EUV spectroscopy. It also marks an important step forward in spectrography and emphasizes the continuing importance of the search and discovery nature of spectroscopic techniques.
TL;DR: In this article, a parton model interpretation of the predictions of quantum chromodynamics in the process e+e−→hadron + anything was presented and the complete list of parameters needed for the study of the scaling violations of fragmentation functions up to the next-to-leading logarithmic approximation was given.
TL;DR: In this paper, an introductory review is given to the study of two-dimensional phase transitions, as most easily observed on lamellar solids, and two examples have been chosen, namely the xenon-graphite and kryptongraphite couples, which have been the subject of the most extensive and detailed studies.
TL;DR: A tropical legume species with aerial nodules, Sesbania 2.1.1 is reported here on, which grows in flooded soils and has two types of nodules: root nodules like other legumes, and stem nodules.
Abstract: The only recorded instances of legume, species with aerial nodules are for Neptunia oleracea [ 11 and Aeschynomene indica [2,3 J . This latter, which grows in flooded soils, has two types of nodules: root nodules like other legumes, and stem nodules. Stem , nodules of A. indica usually are distributed sparsely along the lower stem and look more like small swellings than conventional Rhizobium nodules. We report here on a tropical legume, Sesbania 2.1. Techniques for structural studies
TL;DR: In this article, it is shown that singularities for complex times determine the very high-frequency behavior of the solution and show up in the high-pass filtered signal as bursts centered at the real part of the singularity and with overall amplitude decreasing exponentially with the imaginary part.
Abstract: High-pass filtering of turbulent velocity signals is known to produce intermittent bursts. This is, as shown, a general property of dynamical systems governed by nonlinear equations with band-limited random forces or intrinsic stochasticity. It is shown that singularities for complex times determine the very-high-frequency behavior of the solution and show up in the high-pass filtered signal as bursts centered at the real part of the singularity and with overall amplitude decreasing exponentially with the imaginary part. Near a singularity, nonlinear interactions, however weak they may be on the real axis, acquire unbounded strength. Investigations of singularities by nonperturbative methods is thus essential for quantitative analysis of high-frequency or high-wave-number properties. In contrast to results based on two-point closures, the high-frequency dissipation-range spectrum is actually not universal with respect to the low-frequency forcing. Unlimited intermittency is demonstrated, i.e., the flatness of the high-pass filtered solution grows indefinitely with filter frequency. This gives strong support to a conjecture of Kraichnan [Phys. Fluids 10, 2080 (1967)] about intermittency in the dissipation range of turbulent flows. The analysis is carried out in great detail for the nonlinear Langevin equation $m\stackrel{\ifmmode \dot{}\else \.{}\fi{}}{v}=\ensuremath{-}\ensuremath{\gamma}v\ensuremath{-}{v}^{3}+f(t)$. Lorenz's three mode system and Burgers's model are also discussed. Conjectures are made about Navier-Stokes turbulence which can be checked experimentally and numerically.
TL;DR: The way in which the more rapidly growing Minute+ clones grow and overcome the surrounding Minute cells is described and cell competition is shown to be a result of local interactions between slow- and faster-growing cells.
TL;DR: This paper measured eye fixation patterns made by adult French speakers while they read subject and object relative-clause sentences and found that initial fixations of constituents were similar for all structural types, except for a possible effect of word class within the relative clause.
TL;DR: In this paper, oxygen and carbon isotopic analyses were performed on three surface-dwelling species of planktonic foraminifera, including Globigerinoides ruber, Globigerinella aequilateralis and Globorotalia menardii.
TL;DR: In this article, it is inferred that the Coimbra-Cordoba lineament could have been a suture zone which evolved into an intracontinental left-lateral shear zone during the Variscan orogeny of the Ibero-Armorican arc.
TL;DR: In this paper, the feasibility of using poly(α-hydroxy-acid)s (poly-(glycolic acid), poly(L-lactic acid), L and D-Lactic acid stereocopolymers and copolymers of glycolic and L- and Dlactic acids) for processing bioresorbable bone plates, screws, nails etc..., is questioned in regard to the requirements for effective applications and to the data reported in the open literature.
Abstract: The feasability of using poly(α-hydroxy-acid)s (poly-(glycolic acid), poly(L-lactic acid), L and D-lactic acid stereocopolymers and copolymers of glycolic and L- and D-lactic acids) for processing bioresorbable bone plates, screws, nails etc..., is questioned in regard to the requirements for effective applications and to the data reported in the open literature. Experiments carried out on home-made samples confirm the biocompatibility of these polyesters and the fast resorption of the amorphous compounds. In contrast, our results concerning crystalline poly(L-lactic acid) disagree with those of the literature. The discrepancies might result from differences in the basic material, differences in crystallinity and/or degradation of macromolecules which has been shown to occur sometimes during the elaboration of ready-for-implantation samples. Indeed, quasi-biostable bone plates based on isotactic poly(L-lactic acid) have been obtained according to an elaboration process which preserves the integrity of the synthesized macromolecules. The effects of enantiomeric purity and of implantation time on the tensile strength are reported for a series of welldefined stereocopolymers. Current studies show that highly isotactic poly(lactic acid)s (L/L+D > 92%) are polymers of particular interest for effective applications in bone surgery, especially for the construction of completely resorbable composite devices whose reinforcement consists of poly(glycolic acid) fibers.
TL;DR: In this paper, a theoretical method for calculating the angular scattering curve for any given thin-film multilayer in which the various surfaces and interfaces are assumed to be rough is described.
Abstract: A theoretical method is described for calculating the angular scattering curve for any given thin-film multilayer in which the various surfaces and interfaces are assumed to be rough. The energy that is scattered in any particular direction depends on two factors. The first is solely a function of the characteristics of the ideal multilayer and the observation conditions. The second depends on the roughnesses of the various surfaces, that is, on their autocorrelation and cross-correlation functions. The expressions that are obtained are completely general because no restrictive hypothesis has been developed on the relationship that may exist between the roughnesses of the various interfaces. The principal features of the apparatus used for the scattering measurements are briefly described. Next, several results of calculation and measurement are given as illustrations. The measurements show that polished surfaces of high optical quality often show marked anisotropy.
TL;DR: In this paper, the isoscalar monopole and dipole strength distributions are calculated in the framework of the self-consistent RPA and a comparison of results obtained with various interactions having different values of the compression modulus is made.
TL;DR: In this paper, the basic physical, electrical and optical properties of thin films of doped indium oxide (In2O3) or of tin oxide (SnO2) are reviewed in relation to the dopant concentrations and stoichiometric deviations.
TL;DR: In this paper, generalized rate expressions for adsorption and desorption were derived which specifically take into account the existence of intrinsic and extrinsic precursor states, and which can be readily adapted to account for dissociative or non-dissociative adaption, with and without interactions.
TL;DR: In this article, a quantitative model is proposed, based on the dynamics of plastic waves which accounts for the transition from "normal" to "inverse" transient behaviour with increasing strain, and also explains the opposite effects of stress relaxation and specimen unloading on the restraining transients.
Abstract: Tensile tests were performed on seven commercial polymers at 22° C and at constant true strain rates of 10−4 to 10−1 sec−1. The constant strain rates were imposed on the minimum section of each sample with the aid of a diametral transducer, an exponential function generator and a closed-loop hydraulic testing machine. The polymers investigated were: high and low density polyethylene, polytetrafluoroethylene, polypropylene. polyvinylchloride and polyamide 6 and 66. True yield drops were observed in the rigid glassy polymers, whereas yielding was more gradual in the semi-crystalline or plasticized polymers. Strain rate change tests were also performed, during which one order of magnitude increases and decreases were imposed on the specimens. “Normal” transients were observed at small strains in the samples containing a rubbery phase, while the transients were of an “inverse” nature in the samples containing a glassy phase. With an increase in the strain at which the change was initiated, the “normal” transients changed in character to “inverse”. Transient tests were also performed in which straining was interrupted to permit a period of stress relaxation or of holding in the unloaded condition prior to the resumption of straining. A quantitative model is proposed, based on the dynamics of plastic waves which accounts for the transition from “normal” to “inverse” transient behaviour with increasing strain, and also explains the opposite effects of stress relaxation and of specimen unloading on the restraining transients.