Showing papers by "University of Paris published in 1986"
TL;DR: In this paper, an isotropic elastic damage model is proposed by using the coupling of two damage variables, D t (tensile effects) and D c (compressive effects).
724 citations
TL;DR: In this article, the problem of finding the minimum energy of a point singularity when the location and topological degree of the singularities are prescribed is solved, and it is shown that the only case in which g(x/|x|) minimizes the energy isg=const org(x)=±Rx withR a rotation.
Abstract: Two problems concerning maps ϕ with point singularities from a domain Ω C ℝ3 toS
2 are solved The first is to determine the minimum energy of ϕ when the location and topological degree of the singularities are prescribed In the second problem Ω is the unit ball and ϕ=g is given on ∂Ω; we show that the only cases in whichg(x/|x|) minimizes the energy isg=const org(x)=±Rx withR a rotation Extensions of these problems are also solved, eg points are replaced by “holes,” ℝ3,S
2 is replaced by ℝ
N
,S
N−1 or by ℝ
N
, ℝP
N−1, the latter being appropriate for the theory of liquid crystals
508 citations
TL;DR: On considere le probleme (1): −Δu=f(x,u) sur Ω, u≥0, u±0 sur ∂Ω, ou Ω⊂R N est un domaine borne a frontiere lisse et f[x, u):Ω×[0,∞)→R as discussed by the authors.
Abstract: On considere le probleme (1): −Δu=f(x,u) sur Ω, u≥0, u±0 sur Ω, u=0 sur ∂Ω, ou Ω⊂R N est un domaine borne a frontiere lisse et f[x,u):Ω×[0,∞)→R. On demontre que (1) a au plus une solution. De plus, une solution de (1) existe si et seulement si λ 1 (−Δ−a 0 (x)) 0. (a 0 (x)=lim u→0 f(x,u)/u; a ∞ (x)=lim u→∞ f(x,u)/u.)
471 citations
01 Jan 1986
464 citations
TL;DR: In this article, the authors make a synthesis of the studies on the carbonyl compounds chemistry in the trophosphere by successively examining: measurement methods in the Trophosphere, sources of primary carbonyls, formation of secondary carbonyll compounds in the atmosphere, reactivity of carbinear compounds in an atmosphere.
397 citations
TL;DR: In this article, a review of papers published during the last 10 or 15 years to describe the crack behavior in structures by means of continuum damage mechanics is presented, focusing on a classification of the different methods used and on the different behaviors taken into account: elasticity, plasticity, viscoplasticity; brittle damage, fatigue damage, ductile and creep damages.
363 citations
TL;DR: In this article, the effects of intracellular perfusion of cGMP on the slow inward Ca2+ current (ICa) were examined using isolated, voltage-clamped cells from frog ventricle.
Abstract: The slow inward Ca2+ current, ICa, is fundamental in the initiation of cardiac contraction and neurohormonal regulation of cardiac function. It is increased by beta-adrenergic agonists, which stimulate synthesis of cyclic AMP (cAMP) and cAMP-dependent phosphorylation. The neurotransmitter acetylcholine reduces ICa by an unknown mechanism. There is strong evidence that acetylcholine reduces ICa by decreasing adenylate cyclase activity, but cGMP has also been implicated as ACh stimulates cGMP accumulation and activates cGMP-dependent protein kinase. Application of cGMP decreases contractile force, decreases Ca flux, shortens the duration of action potentials and inhibits Ca-dependent action potentials. Other studies, however, have concluded that cGMP levels do not correlate with contractile force and that cGMP has no effect on ICa. We have therefore examined the effects of intracellular perfusion of cGMP on ICa using isolated, voltage-clamped cells from frog ventricle. We find that cGMP has negligible effects on basal ICa, but greatly decreases the ICa that had been elevated by beta-adrenergic agonists or by intracellular perfusion with cAMP. The decrease of ICa is mediated by cAMP hydrolysis via a cGMP-stimulated cyclic nucleotide phosphodiesterase.
334 citations
TL;DR: An empirically determined similarity matrix which assigns a sequence similarity score between any two sequences of 7 residues in length is proposed which had a prediction accuracy of 62.2% over 3 states for 61 proteins and 63.6% for a new set of 7 proteins not in the original data base.
299 citations
TL;DR: This technique of plating thoracic, thoracolumbar, and lumbar injuries with pedicle screw plates allows the surgeon to reduce and fix a spinal fracture or to perform large approaches and extensive procedures when necessary.
295 citations
TL;DR: In this paper, the authors give a measure of the loss of information due to discretization, when the sampling interval is defined and emphasize differences that depend on whether σ2 is known or unknown.
Abstract: Estimating the parameters of a diffusio,. we give a measure of the loss of information due to discretization, when the sampling interval is. We emphasize differences that depend on whether σ2 is known or unknown.
284 citations
TL;DR: Theoreme d'existence et construction de barrieres fortes en relation avec une inegalite de Hardy for les domaines de R n as discussed by the authors, a.k.a.
Abstract: Theoreme d'existence et construction de barrieres fortes en relation avec une inegalite de Hardy pour les domaines de R n
TL;DR: An optimized method for the analysis of polycyclic aromatic hydrocarbons (PAH) in atmospheric aerosols with short sampling times (1h) has been used to determine the daily variations of PAH in the atmosphere as mentioned in this paper.
TL;DR: A two-step relaxation process involving a fast neutral dissociation followed by the autoionization of the excited fragment has been shown for the first time.
Abstract: Photoelectron spectroscopy excited by monochromatic synchrotron radiation (68-80 eV range) is used to study the Br $3d$ excitation in HBr. The transition to an antibonding orbital is shown to produce a resonant state whose repulsive nature has been observed directly. A two-step relaxation process involving a fast neutral dissociation followed by the autoionization of the excited fragment has been shown for the first time.
TL;DR: In this paper, it was shown that when p >= (N + 2)IN there is no solution of (1.1)-(1.3) and in fact any solution u of u of 1.3 such that u ~ 0 on RN• oo) and lim f u(x, t) Z(x) dx = 0 VT, ~ Co~ N \\ (0}) t~,o RN
Abstract: Consider the Cauchy problem ut -du + u p ----0 on RN• (0, oo) (I.1) u > 0 on RN• (0, oo) (1.2) u(X, O) = c ~(x) on R, N, (1.3) where N _--> 1, c > 0 is a constant and ~(x) denotes the Dirac mass at the origin. A result of BREZlS and FRIEDMAN [6] asserts that if 1 < p < (N + 2)/N, then for every c > 0 there exists a unique 1 solution uc of (1.1)-(1.3). When p >= (N + 2)IN there is no solution of (1.1)-(1.3) and in fact any solution u of (1.1) such that u ~ 0 on RN• oo) and lim f u(x, t) Z(x) dx = 0 VT, ~ Co~ N \\ (0}) t~,o RN
TL;DR: In this article, the kinetics and thermodynamics of batch metal removal reactions by 50 g/l (dry wt) eutrophic or oligotrophic peat particles using Cu 2+, Cd 2÷, Zn 2 ÷ and Ni 2 ǫ concentrations ranging from 0.01 to 100 mM were presented.
TL;DR: In this paper, the dispersion of an alcoholic solution of isobutylcyanoacrylate and oil in water, by interfacial polymerization, allows the formation of nanocapsules with an average diameter of about 200-300 nm.
TL;DR: In this paper, the porosity and the degree of crystallinity of poly(ethylene-co-vinyl alcohol) copolymer were investigated for controlled release of theophylline.
TL;DR: Optimal bounds on the size of minimal factor transducers together with an algorithm for building them are given and analogue results and a simple algorithm are given for the case of subsequential suffix transducers.
TL;DR: Rapid uptake, early saturation, and long exposure of the tissues to the drug may account for the development of toxicity in inner ear and kidney.
Abstract: The kinetics of entry and release of gentamicin was investigated in fluids and tissues of the inner ear of the rat, as well as in renal cortex, and in organs that do not share susceptibility to the toxic effects of aminoglycosides. Various modes of administration were used to achieve different patterns of drug plasma concentrations. Electrophysiological and histological examinations were performed to correlate pharmacokinetics and ototoxicity. Results show that: the uptake of the drug by the inner ear tissues is dose dependent and manifests a rapid saturation kinetics with a concentration plateau of about 1 micrograms/mg of protein. The low ratio of the perilymph and endolymph to plasma concentrations argues against the concept of an accumulation of the drug in the inner ear over drug levels in plasma, which has been considered as the basic mechanism of ototoxicity. In renal cortex, the kinetics appears similar to that of the inner ear but the concentrations achieved are 10-fold higher than in cochlear tissues. In other organs (liver, heart, lung, and spleen), no saturation could be demonstrated within the duration of the experiment. Ototoxicity seems to be related to the penetration of the drug into compartment(s) from which the half-life of disappearance is extremely slow. Rapid uptake, early saturation, and long exposure of the tissues to the drug may account for the development of toxicity in inner ear and kidney.
TL;DR: In this article, the duality of convex functions in general Banach spaces is discussed and the same conclusion holds under the weaker and more geometrical assumption, and a connection with the closed range theorem for linear operators is also emphasized.
Abstract: Publisher Summary This chapter discusses the duality for the sum of convex functions in general Banach spaces. The constraint qualification or a Slater stability condition is discussed in the chapter. The chapter also shows that the same conclusion holds under the weaker and more geometrical assumption. The chapter discusses some corollaries and points out a connection with the closed range theorem for linear operators. The theorem that holds in general Banach spaces is also emphasized. In the special case of a reflexive Banach space the proof is slightly simpler; in particular it is not necessary to invoke the Banach-Dieudonne- Krein-Smulian theorem.
TL;DR: In this article, a search to observe neutrino decays has been performed, and its results are used to set limits on the couplings of a hypothetical massive Neutrino with the ordinary ve and vμ.
01 Jul 1986
TL;DR: An algorithm to find asynchronous CALL statements is given that involves a new dependence test to compute data dependence graphs, which provides better results than previous ones even when no CALL statements are involved.
Abstract: Asynchronous CALL statements are necessary in order to use more than one processor in current multiprocessors. Detecting CALL statements that may be executed in parallel is one way to fill this need. This approach requires accurate approximations of called procedure effects. This is achieved by using new objects called Region and Execution Context. An algorithm to find asynchronous CALL statements is given. It involves a new dependence test to compute data dependence graphs, which provides better results than previous ones even when no CALL statements are involved. This method has been implemented in Parafrase and preliminary results are encouraging.
TL;DR: The effect of a natural and a synthetic peptide derived from k-casein on platelet function was studied and its behaviour was similar to that of the structurally related C-terminal dodecapeptide of human fibrinogen γ-chain.
Abstract: A large number of similarities have previously been noted between the blood and milk clotting phenomena [Jolles, P. (1975) Mol. Cell. Biochem. 7, 73–85; Jolles, P. & Henschen, A. (1982) Trends Biochem. Sci. 7, 325–328]: some analogous features have also been found between fibrinogen and k-casein. In this connection, the effect of a natural and a synthetic peptide derived from k-casein on platelet function was studied: the undecapeptide Met-Ala-Ile-Pro-Pro-Lys-Lys-Asn-Gln-Asp-Lys (residues 106 116 of cow k-casein) inhibited both aggregation of ADP-treated platelets and binding of 125I-fibrinogen to ADP-treated platelets: its behaviour was similar to that of the structurally related C-terminal dodecapeptide of human fibrinogen γ-chain.
TL;DR: In this paper, various peculiarities in the nitrogen and phosphorus geochemical cycles are pointed out, namely a low N: P atomic ratio (6.4) in terrestrial discharges, and a budget well balanced for phosphorus but apparently very deficient in nitrogen in Mediterranean deep waters.
Abstract: Nutrient concentration in the Mediterranean Sea is controlled by water exchanges through the Strait of Gibraltar and by atmospheric and terrestrial inputs. Various peculiarities in the nitrogen and phosphorus geochemical cycles are pointed out, namely a low N: P atomic ratio (6.4) in terrestrial discharges, and a budget well balanced for phosphorus (where terrestrial discharges amount to about 80% of the outflow) but apparently very deficient in nitrogen, despite a high N: P atomic ratio (22), in Mediterranean deep waters. This suggests the possibility of a surprisingly high rate of direct atmospheric N uptake by the Mediterranean ecosystem (possibly seagrasses Posidonia oceanica and pelagic bacterioplankton species).
TL;DR: This study led to two critical developments in multicriteria methods: a method to appraise the impact of imperfect information — which can take several forms — on the ranking was developed and it was applied to 32 sets of values.
TL;DR: Highly purified nuclei were obtained from human sperm without protein loss through the use of CHAPS (3-cholamidopropyl)dimethylammonio]-1-propanesulfonate, a newly available detergent, which reveals two protamines previously considered as two different proteins are in fact the same protein with different degrees of phosphorylation.
TL;DR: From the Triassic to the Present linear belts of calc-alkaline volcanism developed along the southern margin of Eurasia as mentioned in this paper, and their development is related to the closure of the Paleo-Tethys, when fragments of Gondwana (Iran, Afghanistan etc.) were approaching Eurasia.
01 Jan 1986
TL;DR: In this article, the propagation of singularities for semi-linear hyperbolic equations is discussed and second microlocalization can be made along any Lagrangean submanifold.
Abstract: Publisher Summary This chapter presents second microlocalization and discusses the propagation of singularities for semi-linear hyperbolic equations. Fourier integral operators prove that second microlocalization can be made along any Lagrangean submanifold. Using invariance by Fourier integral operators, it is not difficult to define classes of operators mapping. Usual Fourier integral operators and singular diffeomorphisms are particular cases of a much larger class of transformations. They are well-behaved with respect to 2-microlocal calculus. Using invariance by usual Fourier integral operators, it is not difficult to define classes of various operators.