Showing papers by "University of Grenoble published in 1989"

Two-flow model for extragalactic radio jets

Abstract: Different models of extragalactic jet formation have been proposed in the litterature. They usually considered only one population of particles, ascribing one typical bulk velocity to the jet. However from the point of view of plasma physics it seems very likely that beams of particles with different velocity will be generated in the surroundings of the central engine by any kind of jet acceleration mechanism. This can lead to a typical beam-plasma configuration with a slow ambient plasma pervaded by energetic beams which constitute a population inversion and are a potential source of energy and of instability.

A controlled evaluation of a homoeopathic preparation in the treatment of influenza-like syndromes

Abstract: 1. A controlled clinical trial was conducted to assess the effectiveness of a homoeopathic preparation in the treatment of influenza-like syndromes. 2. 237 cases received the test drug and 241 were assigned to placebo. Patients recorded their rectal temperature twice a day, and the presence or absence of five cardinal symptoms (headache, stiffness, lumbar and articular pain, shivers) along with cough, coryza and fatigue. 3. Recovery was defined as a rectal temperature less than 37.5 degrees C and complete resolution of the five cardinal symptoms. 4. The proportion of cases who recovered within 48 h of treatment was greater among the active drug group than among the placebo group (17.1% against 10.3%, P = 0.03). 5. The result cannot be explained given our present state of knowledge, but it calls for further rigorously designed clinical studies.

The blueschists along the Indus Suture Zone in Ladakh, NW Himalaya

Abstract: Blueschists occur along the Indus Suture Zone in Ladakh as tectonic thrust slices, as isolated blocks within melange units and as pebbles within continental detrital series. In the Shergol-Baltikar section high-pressure rocks within the Melange unit lie between the Dras-Naktul-Nindam nappes in the north and the Lamayuru units in the south. The blueschists are imbricated with melange formation of probably upper Cretaceous age. They are overlain discordantly by the Shergol conglomerate of post Eocene (Oligo-Miocene ?) age. Blueschist lithologies are dominated by volcanoclastic rock sequences of basic material with subordinate interbedding of cherts and minor carbonates. Mineral assemblages in metabasic rocks are characterized by lawsonite-glaucophane/crossite-Na-pyroxene-chlorite-phengite-titanite ± albite ± stilpnomelane. In the quartz bearing assemblages garnet is present but omphacite absent. P-T estimates indicate temperatures of 350 to 420°c and pressures around 9–11 kbar. Geochemical investigations show the primary alkaline character of the blueschist, which suggests an oceanic island or a transitional MORB type primary geotectonic setting. K/Ar isotopic investigations yield middle Cretaceous ages for both whole rocks and minerals. Subduction related HP-metamorphism affecting the Mesozoic Tethyan oceanic crust developed contemporaneously with magmatism in the Dras volcanic are and the Ladakh batholith. Subsequent collision of India with Asia obducted relics of subduction zone material which later became involved in nappe emplacement during the Himalayan mountain building.

Discovery of CO emission from NGC 1275

Abstract: CO radio emission has been discovered in both the J=1-0 and J=2-1 rotational lines from the elliptical galaxy NGC 1275. The CO, which may condense from the cooling flow by means of which mass is thought to be accumulating, exhibits such a small velocity dispersion that it may collapse into stars before it virializes in the gravitational potential of this galaxy. If the star formation rate is as high as presently calculated, the initial mass function will be weighted toward the production of low-mass stars.

Direct segregation analysis of reciprocal translocations: a study of 283 sperm karyotypes from four carriers.

Abstract: Using the technique of in vitro human-hamster fertilization, sperm of four men heterozygous for 4 reciprocal translocations--t(4;17),t(5;13),t(6;7), and t(9;18)--was studied. Frequencies of numerical abnormalities unrelated to the translocations range from 8.3% to 13.3%, and the incidence of imbalances ranges from 23.0% to 66.0%. Results are pooled with data from the nine other reciprocal translocations reported elsewhere, and the combined data demonstrate that male meiotic segregation is not random: whatever the type of translocation may be, the distribution of imbalances in sperm is constant, with approximately 72.0% adjacent 1, 18.5% adjacent 2, and 9.5% 3:1 segregations. The same prevalence of adjacent 1 segregations as that reported at term for translocations of paternal origin is observed. There is a strong postzygotic elimination process; for a given translocation it affects selectively the maximum-imbalance zygotes so that imbalanced segregations observed at term are always predetermined.

Sawtooth oscillations in ion cyclotron emission from JET

Abstract: During ohmically heated high current deuterium discharges in JET, inverted sawtooth oscillations in the superthermal ion cyclotron emission (ICE) have been detected which cannot be accounted for by fluctuations in the antenna-plasma coupling efficiency. This observation confirms the spatial localization of the ICE source in the edge plasma, close to the position of the detecting RF antenna on the low field side of the torus. Strong time correlation is observed between the inverted ICE sawteeth and those seen in an outer soft X-ray channel and in Dα emission from the limiter. Time delay data show that the ICE sawtooth peaks coincide with the arrival of sawtooth heat pulses in the edge plasma which are delayed by 17 ms with respect to the central sawtooth crash. The ICE sawtooth oscillations are interpreted in terms of local changes in the thermonuclear D-D fusion reactivity in the edge plasma. The observations are consistent with the interpretation of ICE as the result of maser action by an energetic ion population.

Turbulence and vortices in rotating fluids

Abstract: The most striking effect of rotation on fluid motion is the tendency for the motion to become two-dimensional. Unique to rotating fluids is also the manifestation of boundary effects through Ekman pumping and inherent in these two processes is the property of rotating fluids to sustain wave motions. Considerable progress has been made recently on turbulence in rotating fluids. The mechanism of energy and enstrophy cascades is better understood and new phenomena like the transition to a rotationally dominated state and the possibility of vorticity concentration have been demonstrated. This has opened up new question concerning vortex dynamics (geostrophic and ageostrophic vortices), vortex waves, breakdown, and merging conditions in homogeneous and rotating, stratified fluid. After giving some examples of rotation effects in geophysical and industrial flows and introducing the basic concepts of rotating fluids, the paper emphasizes rotational effects on turbulence and the related problems of vortex formation and dynamics.

Microangiopathy of endoneurial vessels in hypoxemic chronic obstructive pulmonary disease (COPD). A quantitative ultrastructural study.

Abstract: A peripheral neuropathy has been reported in patients with chronic respiratory insufficiency due to chronic obstructive pulmonary disease (COPD). It is mainly characterized by axonal degeneration, secondary demyelination and abnormal endoneurial vessels. The pathogenesis of these lesions remains obscure. To investigate whether relationships exist between neuritic and vascular lesions, a qualitative and quantitative ultrastructural study was performed on nerve biopsies in 13 patients with chronic respiratory insufficiency due to COPD, and in 9 normal controls without pulmonary lesions. A computer-assisted multiple regression analysis taking into account clinical, electrophysiological, biological and morphometric parameters was performed. Statistically significant differences in the endoneurial structure of microvessels were: (1) thickening of the basement membrane; (2) narrowing of the lumen; (3) mural pericytic debris deposits, occurring in the COPD group. In the latter, hypercapnia correlated positively with nerve fibers lesions (P=0.03) and endothelial area (P=0.03). No correlations were found between age and other parameters. These findings highlight the fact that the microangiopathy in peripheral nerves in patients with COPD may be diffuse and essentially due to hypoxia and reduction in blood flow, as in diabetic neuropathy.

Models of human memory.

Abstract: The capacity to store and retrieve information is a property common to biological organisms and certain artefacts. Psychological models of human memory fall into two rival classes: a) "bionic" models which draw inspiration from the structural and functional properties of the central nervous system (computo bionic models); b) "symbolic information processing" models in which the inspiration for description and explanation of natural processes is drawn from the structural and functional properties of Von Neumann computers (computo-symbolic models).

Spherical Varieties an Introduction

Abstract: When one studies complex algebraic homogeneous spaces it is natural to begin with the ones which are complete (i.e. compact) varieties. They are the “generalized flag manifolds”. Their occurence in many problems of representation theory, algebraic geometry, … make them an important class of algebraic varieties. In order to study a noncompact homogeneous space G/H, it is equally natural to compactify it, i.e. to embed it (in a G- equivariant way) as a dense open set of a complete G-variety. A general theory of embeddings of homogeneous spaces has been developed by Luna and Vust [LV]. It works especially well in the so-called spherical case: G is reductive connected and a Borei subgroup of G has a dense orbit in G/H. (This class includes complete homogeneous spaces as well as algebraic tori and symmetric spaces). A nice feature of a spherical homogeneous space is that any embedding of it (called a spherical variety) contains only finitely many G-orbits, and these are themselves spherical. So we can hope to describe these embeddings by combinatorial invariants, and to study their geometry. I intend to present here some results and questions on the geometry (see [LV], [BLV], [BP], [Lun] for a classification of embeddings).

Comparison of light microscopic grading and morphometric features in cytological breast cancer specimens.

Abstract: Summary A study was set up to investigate correlations between different light microscopic grades and morphometric features in cytological breast cancer specimens and to evaluate the discriminative power of morphometry for the three grades. 76 slides (smears and imprints) were graded independently in two different laboratories, and the 54 unequivocally graded slides were used as a training set for computing classification rules. In all slides, 1 00 nuclei and their nucleoli were measured on a graphic tablet at a final magnification of 2800x . A total of 43 morphometric features was evaluated. Univariate analysis showed significantly different values for most of the morphometric features for the three grades. Discriminant analysis revealed that a combination of the mean nuclear area and the number of mitoses per slide provided optimal discrimination between grades one and two (87.5% correct classification). One more feature (mean nuclear shape factor) was needed to obtain optimal discrimination between grades two and three (83.3% correct classifications). 16 of the 22 (72.7%) equivocally graded slides could be classified with high probability using these classification rules. We conclude that morphometry has discriminative power for the three grades in cytologic breast cancer specimens and may therefore be a useful instrument for classification of difficult cases.

Vingt ans d'accidents de ski au service d'urgence et de traumatologie de l'Hôpital-Sud de Grenoble : évolution de ces accidents au cours de ces 20 ans (d'après une statistique de 17120 accidentés) : 1968-1988

Abstract: Le travail que nous presentons, base sur les 17.120 accidentes de ski qui ont ete traites entre 1968 et 1988 dans le service d'urgence et de traumatologie de l'Hopital-Sud de Grenoble (Pr. H. BEZES) se propose de montrer l'evolution de la traumatologie du ski au cours des 20 dernieres annees : dans ce service, le nombre de ces accidentes est alle en augmentant a chaque saison de 1968 a 1974, pour se stabiliser, depuis 14 a 15 ans, aux alentours d'un millier d'accidentes de ski par saison, dont, depuis 8 a 9 ans, 11 a 12% d'accidentes de ski de fond. Apres un historique des accidents de ski, base essentiellement sur : les travaux presentes aux 18 congres de la S.I.T.E.M.S.H. (de 1954 a 1970), et ceux presentes aux 8 congres de l'I.S.S.S. (de 1974 a 1989). Sont exposees, 1/ les conditions techniques mises en œuvre pour faire face -durant les 4 mois d'hiver- a cet afflux de traumatises, service au complet, "attendant" tous les jours a partir de 13 heures l'arrivee des eventuels skieurs ... pratique, qui fait tres frequemment appel, dans les fractures de l'adulte, a l'osteosynthese stable et solide. Et sont successivement envisagees les differentes lesions rencontrees, qui, du fait de l'orientation du service sont essentiellement des lesions des membres ne posant pas, en principe, de problemes d'ordre vital (930 luxations, 5.273 entorses et 9.294 fractures, dont seulement 189 fractures ouvertes -soit 2%-). - Les membres superieurs tout d'abord, avec 4.231 accidentes, -soit un peu plus de 24%- (1.782 lesions de l'epaule et de la ceinture scapulaire, 1.827 lesions du poignet et de la main, 486 lesions du coude et de l'avant-bras, 136 lesions du bras). - Les membres inferieurs, avec 11.584 accidentes -soit 65 a 66%- (les lesions de la partie haute du membre inferieur, les lesions sous-jacentes a la diaphyse femorale : 1811 lesions du cou-de-pied, 3.882 lesions du genou, 5.013 fractures de jambe). - A chacun de ces chapitres, comparaison entre les elements de notre statistique et ceux emanant des differents auteurs qui, de par le monde, se sont interesses a la traumatologie du ski. - Considerations sur les avantages de cette organisation qui a permis -entre autre- de syntheser 3.843 skieurs accidentes -le plus souvent etrangers a la region grenobloise-, avec les incidences psychologiques et economiques entrainees par une telle attitude. Aux pouvoirs publics de dire, si une organisation telle que celle decrite dans ce travail -mise depuis 21 ans au service des skieuses et des skieurs accidentes- est -oui ou non- a imiter.

Cramer-Rao bounds for AR parameter and reflection coefficient estimators

Abstract: The finite examples Cramer-Rao bound for the autoregressive parameters of a Gaussian autoregressive model is given in closed form. Quick algorithms for computing this bound for the autoregressive parameters and also for the reflection coefficients are presented. The exact bounds are of interest since they can differ appreciably from the asymptotic bounds. If replicated independent records are available (as in some spatial array processing problems), the exact bounds will be approached when the number of replications goes to infinity but the asymptotic bound will not, since the record length remains finite. >

Protonium annihilation in optical models

Abstract: We calculate the wave-functions, energy shifts and widths of low lying protonium states using different optical potentials (Dover-Richard, Kohno-Weise). The importance of tensor and isospin coupling is studied and the initial state distortion is compared for protonium annihilation andp¯p annihilation in flight at low energy. We study the range of distances at which annihilation actually occurs in protonium. We also analyse the effect of the initial state interaction on two meson branching ratios and underline that it may dramatically change the predictions of those microscopic models which are based only on phase space and simple quark diagrams.

Laws of large numbers for semimartingales with applications to stochastic regression

Abstract: Strong laws of large numbers for matrix-normalised vector-valued local martingales are established. The results are derived from strong laws for positive local submartingales and purely discontinuous local martingales and a Borel-Cantelli-type lemma for local martingales of finite variation. The multivariate strong laws are applied to study strong consistency of estimates in stochastic linear regression models.

Measurement of the average lifetime of B hadrons

Abstract: The average lifetime ofB hadrons produced in hadronicZ 0 decays has been measured with the DELPHI detector at LEP. The measurement is based on the analysis of the impact parameter distributions of highp t muons and hadrons. The resulting meanB lifetimes are τ B =(1.30±0.10±0.08)ps and τ B =(1.27±0.04±0.12)ps respectively, giving a combined value of τ B =(1.28±0.10)ps. The hadronic sample was also used to measure the partialZ 0 width $${{\Gamma _{b\bar b} } \mathord{\left/ {\vphantom {{\Gamma _{b\bar b} } {\Gamma _h }}} \right. \kern- ulldelimiterspace} {\Gamma _h }}$$ and gave a value of 0.222 −0.031 +0.033 ±0.017.

Geodynamic implications of Devonian silicic arc magmatism in the Sierra Nevada and Klamath Mountains, California

Abstract: Most proposed geodynamic models integrate the northern Sierra Nevada and eastern Klamath Mountains in a single island-arc system. New petrological and geochemical data show that the Upper Devonian Sierra Buttes Formation of the northern Sierra Nevada displays important differences from the Lower Devonian Balaklala Formation of the eastern Klamath Mountains. The cale-alkalic affinity of the Sierra Buttes rhyolites (light rare earth element [REE] enriched, low e Nd ) suggests that they were erupted in a continent-based island arc. In contrast, the Lower Devonian Balaklala low-K tholeiitic rhyolites (light REE depleted, high e Nd ) are considered to be part of an intraoceanic island-arc sequence. Moreover, the Paleozoic tectogenesis of these two island-arc sequences is different. The Lower Devonian Balaklala rhyolites were affected by the Late Devonian-Early Carboniferous orogeny, whereas the Sierra Buttes Formation is on basement already affected by a pre-Late Devonian deformation. Therefore, at least after Carboniferous time and before Late Triassic time, the eastern Klamath and northeastern Sierra Nevada island arcs cannot be considered lateral counterparts.

Optimum computation of capacitance coefficients of multilevel interconnecting lines for advanced package

Abstract: A general procedure for computing the capacitance coefficients of multilevel interconnections in multilayered dielectric medium is given. The electromagnetic concept of total charge density is applied. It makes it possible to obtain integral equations between scalar potential and charge density distributions. These equations are solved by the method of moments technique. To optimize the computational algorithm, special consideration is given to the limitation of the dimensions of the dielectric interfaces. Simple criteria are introduced to divide the interfaces into an optimum number of elementary parts. Theoretical results thus obtained agree closely with the experimental results from test vehicles. >

Mise au point sur les quinolones de troisième génération

Abstract: Cette mise au point sur les quinolones de troisieme generation permet de degager plusieurs points importants sur cette nouvelle classe d'antibiotiques systemiques. Dans la premiere partie, concernant la pharmacie chimique, sont detailles la relation structure-activite a savoir qu'un halogene, le fluor, augmente fortement leur activite, ainsi que le mecanisme d'action, par inhibition enzymatique de l'A.D.N. gyrase bacterienne. Dans la deuxieme partie, s'interessant a la pharmacologie, sont a retenir les qualites pharmacocinetiques telles que la longue demi-vie d'elimination, la bonne diffusion dans la plupart des tissus et des milieux extra-vasculaires, un large spectre antimicrobien et une bonne tolerance. Enfin, ce travail souligne l'importance d'une bonne prescription lors d'une anti-biotherapie par ces quinolones.

Neurinomes de l'acoustique : problèmes actuels à propos d'une série de 151 cas

Abstract: Notre serie de 151 neurinomes de l'acoustique beneficie d'une standardisation rigoureuse quant au volume tumoral (stades de Koos), a la motricite faciale definitive (grades de House) et a la conservation de l'audition (nouvelle classification). Le diagnostic precoce concerne particulierement les nombreuses formes atypiques afin de beneficier au maximum des performances de l'imagerie par resonance magnetique. Le monitoring peroperatoire du nerf facial par capteur de pression permet de preserver une motricite faciale de grade 1 ou 2 dans plus de 82% des abords translabyrinthiques, quel que soit le stade. L'audition est conservee dans 1 tentative sur 3. La selection doit etre renforcee. Le monitoring peroperatoire auditif n'a pas encore fait veritablement la preuve de son efficacite. L'abord translabyrinthique confere le maximum de securite, particulierement en cas de tumeur volumineuse ou chez le vieillard. Cependant, cette chirurgie exige une surveillance continue durant les 48 premieres heures. L'amelioration des techniques d'exerese n'elimine pas le risque de recidive ; une surveillance prolongee par l'I.R.M. est necessaire. La cinetique de croissance tumorale reste imprevisible. Les methodes immunohistochimiques proposees devraient preciser les caracteres evolutifs. En cas de neurinome unilateral, l'abord translabyrinthique est indique chaque fois que l'audition n'est plus fonctionnelle. Les abords suspetreux ou retrosigmoidien sont indiques respectivement pour tenter de conserver l'audition lors de stade I ou de petit stade II. En cas de neurinome bilateral ou sur oreille unique, l'abord translabyrinthique est indique quand l'audition est perdue ou quand la tumeur comprime le tronc cerebral.

La maladie de Behcet : à propos d'un cas de neuro-Behcet d'aspect pseudo-tumoral

Abstract: Definie comme une vascularite a tropisme veineux, la maladie de Behcet fait partie des maladies de systeme du fait de ses multiples localisations viscerales. Bien que decrite il y a plus de 50 ans, elle reste d'actualite en raison des problemes diagnostiques, epidemiologiques, etiopathogeniques et therapeutiques qu'elle pose. L'imagerie cerebrale etait consideree jusqu'a present comme peu specifique et peu utile pour le diagnostic des formes neurologiques. La tomodensitometrie et surtout la resonance magnetique nucleaire permettent aujourd'hui de detecter precocement les lesions nerveuses centrales, notamment au niveau du tronc cerebral. Le pronostic du Neuro-Behcet, considere comme rapidement defavorable, peut etre radicalement modifie, par l'utilisation precoce des traitements immunosuppresseurs. Cette these est illustree par un cas ce Neuro-Behcet d'aspect pseudo-tumoral a la tomodensitometrie, dont le diagnostic n'a pu etre fait qu'apres biopsies (en condition stereotaxiques) et examen ultrastrutural des lesions nerveuses centrales. L'instauration precoce d'un traitement immunosuppresseur en a spectaculairement ameliore l'evolution.

Asymptotic normality of double-indexed linear permutation statistics

Abstract: The paper provides sufficient conditions for the asymptotic normality of statistics of the form ΣaijbRiRj, whereaijandbijare real numbers andRiis a random permutation.

Electronic structure and conformational statistics of conjugated polymers in solution: A Fermi system with annealed disorder.

Abstract: Proposition d'une nouvelle approche pour l'etude des proprietes electroniques et conformationnelles de polymeres conjugues, solubles. Traitement d'une chaine par un modele de liaison forte unidimensionnel avec desordre recuit. Configuration explicite de plusieurs resultats attendus et obtention de nouveaux resultats. En particulier, mise en evidence des effets de forte localisation et de l'existence de regions rigides contenant des electrons