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Sample records for numeriques voxelises associes

  1. Study of the influence of radionuclide biokinetics on in vivo counting using voxel phantoms; Etude de l'influence de la biocinetique des radionucleides sur la mesure anthroporadiametrique a l'aide de fantomes numeriques voxelises

    Energy Technology Data Exchange (ETDEWEB)

    Lamart, St.

    2008-10-15

    The in vivo measurement is an efficient method to estimate the retention of activity in case of internal contamination. However, it is currently limited by the use of physical phantoms for the calibration, not enabling to reproduce neither the morphology of the measured person nor the actual distribution of the contamination. The current method of calibration therefore leads to significant systematic uncertainties on the quantification of the contamination. To improve the in vivo measurement, the Laboratory of Internal Dose Assessment (LEDI, IRSN) has developed an original numerical calibration method with the OEDIPE software. It is based on voxel phantoms created from the medical images of persons, and associated with the MCNPX Monte Carlo code of particle transport. The first version of this software enabled to model simple homogeneous sources and to better estimate the systematic uncertainties in the lung counting of actinides due to the detector position and to the heterogeneous distribution of activity inside the lungs. However, it was not possible to take into account the dynamic feature, and often heterogeneous distribution between body organs and tissues of the activity. Still, the efficiency of the detection system depends on the distribution of the source of activity. The main purpose of the thesis work is to answer to the question: what is the influence of the biokinetics of the radionuclides on the in vivo counting? To answer it, it was necessary to deeply modify OEDIPE. This new development enabled to model the source of activity more realistically from the reference biokinetic models defined by the ICRP. The first part of the work consisted in developing the numerical tools needed to integrate the biokinetics in OEDIPE. Then, a methodology was developed to quantify its influence on the in vivo counting from the results of simulations. This method was carried out and validated on the model of the in vivo counting system of the LEDI. Finally, the

  2. Application of voxelised numerical phantoms linked to the M.C.N.P. Monte Carlo code to the realistic measurement in vivo of actinides in the lungs and contaminated wounds; Application des fantomes numeriques voxelises associes au code Monte Carlo MCNP a la mesure in vivo realiste des actinides dans les poumons et les plaies contaminees

    Energy Technology Data Exchange (ETDEWEB)

    Noelle, P

    2006-12-15

    In vivo lung counting, one of the preferred methods for monitoring people exposed to the risk of actinide inhalation, is nevertheless limited by the use of physical calibration phantoms which, for technical reasons, can only provide a rough representation of human tissue. A new approach to in vivo measurements has been developed to take advantage of advances in medical imaging and computing; this consists of numerical phantoms based on tomographic images (CT) or magnetic resonance images (R.M.I.) combined with Monte Carlo computing techniques. Under laboratory implementation of this innovative method using specific software called O.E.D.I.P.E., the main thrust of this thesis was to provide answers to the following question: what do numerical phantoms and new techniques like O.E.D.I.P.E. contribute to the improvement in calibration of low-energy in vivo counting systems? After a few developments of the O.E.D.I.P.E. interface, the numerical method was validated for systems composed of four germanium detectors, the most widespread configuration in radio bioassay laboratories (a good match was found, with less than 10% variation). This study represents the first step towards a person-specific numerical calibration of counting systems, which will improve assessment of the activity retained. A second stage focusing on an exhaustive evaluation of uncertainties encountered in in vivo lung counting was possible thanks to the approach offered by the previously-validated O.E.D.I.P.E. software. It was shown that the uncertainties suggested by experiments in a previous study were underestimated, notably morphological differences between the physical phantom and the measured person. Some improvements in the measurement procedure were then proposed, particularly new bio-metric equations specific to French measurement configurations that allow a more sensible choice of the calibration phantom, directly assessing the thickness of the torso plate to be added to the Livermore phantom based on the weight and height of the measured person. Lastly, the study underlined the interest of numerical phantoms and Monte Carlo simulation through actual contamination cases of lungs or wounds, which are impossible to study using traditional methods. In the case of contaminated wounds, this method was used to adjust the level of the retained activity in an actual injury on a hand and should improve the determination of source geometry, thereby refining the dose calculation. Personalized calibration of counting systems (for morphological purposes or distribution of radionuclides in the body) appears possible thanks to this innovative method and represents an important step towards implementation of personalized dosimetry. (author)

  3. Microdosimetry of alpha particles for simple and 3D voxelised geometries using MCNPX and Geant4 Monte Carlo codes.

    Science.gov (United States)

    Elbast, M; Saudo, A; Franck, D; Petitot, F; Desbrée, A

    2012-07-01

    Microdosimetry using Monte Carlo simulation is a suitable technique to describe the stochastic nature of energy deposition by alpha particle at cellular level. Because of its short range, the energy imparted by this particle to the targets is highly non-uniform. Thus, to achieve accurate dosimetric results, the modelling of the geometry should be as realistic as possible. The objectives of the present study were to validate the use of the MCNPX and Geant4 Monte Carlo codes for microdosimetric studies using simple and three-dimensional voxelised geometry and to study their limit of validity in this last case. To that aim, the specific energy (z) deposited in the cell nucleus, the single-hit density of specific energy f(1)(z) and the mean-specific energy were calculated. Results show a good agreement when compared with the literature using simple geometry. The maximum percentage difference found is MCNPX for calculation time is 10 times higher with Geant4 than MCNPX code in the same conditions.

  4. Transfert radiatif numerique pour un code SPH

    Science.gov (United States)

    Viau, Joseph Edmour Serge

    2001-03-01

    Le besoin de reproduire la formation d'etoiles par simulations numeriques s'est fait de plus en plus present au cours des 30 dernieres annees. Depuis Larson (1968), les codes de simulations n'ont eu de cesse de s'ameliorer. D'ailleurs, en 1977, Lucy introduit une autre methode de calcul venant concurrencer la methode par grille. Cette nouvelle facon de calculer utilise en effet des points a defaut d'utiliser des grilles, ce qui est une bien meilleure adaptation aux calculs d'un effondrement gravitationnel. Il restait cependant le probleme d'ajouter le transfert radiatif a un tel code. Malgre la proposition de Brookshaw (1984), qui nous montre une formule permettant d'ajouter le transfert radiatif sous la forme SPH tout en evitant la double sommation genante qu'elle implique, aucun code SPH a ce jour ne contient un transfert radiatif satisfaisant. Cette these presente pour la premiere fois un code SPH muni d'un transfert radiatif adequat. Toutes les difficultes ont pu etre surmontees afin d'obtenir finalement le transfert radiatif "vrai" qui survient dans l'effondrement d'un nuage moleculaire. Pour verifier l'integrite de nos resultats, une comparaison avec le nonisothermal test case de Boss & Myhill (1993) nous revele un resultat fort satisfaisant. En plus de suivre fidelement la courbe de l'evolution de la temperature centrale en fonction de la densite centrale, notre code est exempt de toutes les anomalies rencontrees par les codes par grille. Le test du cas de la conduction thermique nous a lui aussi servit a verifier la fiabilite de notre code. La aussi les resultats sont fort satisfaisants. Faisant suite a ces resultats, le code fut utilise dans deux situations reelles de recherche, ce qui nous a permis de demontrer les nombreuses possibilites que nous donne notre nouveau code. Dans un premier temps, nous avons tudie le comportement de la temperature dans un disque d'accretion durant son evolution. Ensuite nous avons refait en partie une experience de Bonnell

  5. Creation and application of voxelised dosimetric models, and a comparison with the current methodology as used for the International Commission on Radiological Protection's Reference Animals and Plants.

    Science.gov (United States)

    Higley, K; Ruedig, E; Gomez-Fernandez, M; Caffrey, E; Jia, J; Comolli, M; Hess, C

    2015-06-01

    Over the past decade, the International Commission on Radiological Protection (ICRP) has developed a comprehensive approach to environmental protection that includes the use of Reference Animals and Plants (RAPs) to assess radiological impacts on the environment. For the purposes of calculating radiation dose, the RAPs are approximated as simple shapes that contain homogeneous distributions of radionuclides. As uncertainties in environmental dose effects are larger than uncertainties in radiation dose calculation, some have argued against more realistic dose calculation methodologies. However, due to the complexity of organism morphology, internal structure, and density, dose rates calculated via a homogenous model may be too simplistic. The purpose of this study is to examine the benefits of a voxelised phantom compared with simple shapes for organism modelling. Both methods typically use Monte Carlo methods to calculate absorbed dose, but voxelised modelling uses an exact three-dimensional replica of an organism with accurate tissue composition and radionuclide source distribution. It is a multi-stage procedure that couples imaging modalities and processing software with Monte Carlo N-Particle. These features increase dosimetric accuracy, and may reduce uncertainty in non-human biota dose-effect studies by providing mechanistic answers regarding where and how population-level dose effects arise.

  6. Calculation of reactivity by digital processing; Calcul de la reactivite par traitement numerique

    Energy Technology Data Exchange (ETDEWEB)

    Hedde, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1968-12-01

    With a view to exploring the new possibilities offered by digital techniques, a description is given of the optimum theoretical conditions of a computation of the realtime reactivity using counting samples (obtained from a nuclear reactor). The degree to which these optimum conditions can be attained depends on the complexity of the processing which can be accepted. A compromise thus has to be made between the accuracy required and the simplicity of the equipment carrying out the processing. An example is given, using a relatively simple structure, which gives an idea of the accuracy of the results obtained over a wide range of reactor power. (author) [French] Dans le but d'explorer les possibilites nouvelles des techniques numeriques, on decrit les conditions theoriques optimales d'un calcul de la reactivite en temps reel a partir d'echantillons de comptage (en provenance d'un reacteur nucleaire). Ces conditions optimales peuvent etre approchees d'autant mieux que l'on accepte un traitement plus complexe. Un compromis est donc a faire entre la precision desiree et la simplicite du materiel assurant le traitement. Un exemple adoptant une structure de complexite reduite permet de juger de la precision des resultats obtenus sur une importante plage d'evolution de la puissance. (auteur)

  7. Modelisation numerique et validation experimentale d'un systeme de protection contre le givre par elements piezoelectriques

    Science.gov (United States)

    Harvey, Derek

    Le degivrage au moyen d'actuateurs piezoelectriques est considere comme une avenue prometteuse pour le developpement de systemes a faible consommation d'energie applicables aux helicopteres legers. Ce type de systeme excite des frequences de resonances d'une structure pour produire des deformations suffisantes pour rompre l'adherence de la glace. Par contre, la conception de tel systeme demeure generalement mal comprise. Ce projet de maitrise etudie l'utilisation de methodes numeriques pour assister la conception des systemes de protection contre le givre a base d'elements piezoelectriques. La methodologie retenue pour ce projet a ete de modeliser differentes structures simples et de simuler l'excitation harmonique des frequences de resonance au moyen d'actuateurs piezoelectriques. Le calcul des frequences de resonances ainsi que la simulation de leur excitation a ensuite ete validee a l'aide de montages experimentaux. La procedure a ete realisee pour une poutre en porte-a-faux et pour une plaque plane a l'aide du logiciel de calcul par elements finis, Abaqus. De plus, le modele de la plaque plane a ete utilise afin de realiser une etude parametrique portant sur le positionnement des actuateurs, l'effet de la rigidite ainsi que de l'epaisseur de la plaque. Finalement, la plaque plane a ete degivree en chambre climatique. Des cas de degivrage ont ete simules numeriquement afin d'etudier la possibilite d'utiliser un critere base sur la deformation pour predire le succes du systeme. La validation experimentale a confirme la capacite du logiciel a calculer precisement a la fois les frequences et les modes de resonance d'une structure et a simuler leur excitation par des actuateurs piezoelectriques. L'etude revele que la definition de l'amortissement dans le modele numerique est essentiel pour l'obtention de resultats precis. Les resultats de l'etude parametrique ont demontre l'importance de minimiser l'epaisseur et la rigidite afin de reduire la valeur des frequences

  8. Direct digital control of furnaces irradiated in nuclear reactors; Surveillance et regulation multiplexee par calculateur numerique de fours irradies

    Energy Technology Data Exchange (ETDEWEB)

    Joumard, R. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1969-07-01

    An experimental direct digital control system has been realised in the 'C.E.N.G.', in order to verify that a computer makes easier the control of the experiments done in the nuclear reactors and to solve the theoretical and technical difficulties. The regulation is applied to thermal processes. The sampled data systems theory permits to choose the type of an efficient and simple digital compensator, and to establish a diagram which gives the values of the correcting parameters (obtained by minimizing the difference between the output and the input when perturbations occur). The programme execute, in simultaneity, supervision and regulation. Complex possibilities of printing out measures and alarms existed. The computer works out an incremental correction which makes step motors to turn. These motors act on the heating organs. The theoretical values and answers have been confirmed. The accuracy was limited essentially by the input quantification (1/1000 th). The comfort of such a system has been noticeable. (author) [French] Une installation de controle numerique direct fut realisee a titre experimental au C.E.N.G pour verifier qu'un ordinateur rendait plus aisee l'exploitation des experiences faites en pile nucleaire et pour degager les difficultes theoriques et techniques. La regulation s'applique a des processus thermiques. La theorie des systemes echantillonnes a permis de choisir un type de correcteur numerique simple et efficace et d'etablir un abaque qui donne les valeurs des parametres correcteurs minimisant les ecarts enregistres entre la reponse et la consigne en presence de perturbations. Le programme effectuait simultanement de la surveillance et de la regulation. Une restitution complexe des informations et des alarmes sur machine a ecrire etait possible. Le calculateur elaborait une correction incrementielle qui faisait tourner des moteurs pas a pas, lesquels commandaient les organes de puissance de chauffage. Les valeurs

  9. Etude numerique et experimentale de la reponse vibro-acoustique des structures raidies a des excitations aeriennes et solidiennes

    Science.gov (United States)

    Mejdi, Abderrazak

    Les fuselages des avions sont generalement en aluminium ou en composite renforces par des raidisseurs longitudinaux (lisses) et transversaux (cadres). Les raidisseurs peuvent etre metalliques ou en composite. Durant leurs differentes phases de vol, les structures d'avions sont soumises a des excitations aeriennes (couche limite turbulente : TBL, champs diffus : DAF) sur la peau exterieure dont l'energie acoustique produite se transmet a l'interieur de la cabine. Les moteurs, montes sur la structure, produisent une excitation solidienne significative. Ce projet a pour objectifs de developper et de mettre en place des strategies de modelisations des fuselages d'avions soumises a des excitations aeriennes et solidiennes. Tous d'abord, une mise a jour des modeles existants de la TBL apparait dans le deuxieme chapitre afin de mieux les classer. Les proprietes de la reponse vibro-acoustique des structures planes finies et infinies sont analysees. Dans le troisieme chapitre, les hypotheses sur lesquelles sont bases les modeles existants concernant les structures metalliques orthogonalement raidies soumises a des excitations mecaniques, DAF et TBL sont reexamines en premier lieu. Ensuite, une modelisation fine et fiable de ces structures est developpee. Le modele est valide numeriquement a l'aide des methodes des elements finis (FEM) et de frontiere (BEM). Des tests de validations experimentales sont realises sur des panneaux d'avions fournis par des societes aeronautiques. Au quatrieme chapitre, une extension vers les structures composites renforcees par des raidisseurs aussi en composites et de formes complexes est etablie. Un modele analytique simple est egalement implemente et valide numeriquement. Au cinquieme chapitre, la modelisation des structures raidies periodiques en composites est beaucoup plus raffinee par la prise en compte des effets de couplage des deplacements planes et transversaux. L'effet de taille des structures finies periodiques est egalement pris en

  10. Modelisation Numerique De L'Interaction Sol-Structure Lors Du Phenomene De Fontis

    CERN Document Server

    Caudron, Matthieu; Heib, Marwan Al

    2008-01-01

    This article focuses on the simulation of soil-structure interaction during a sinkhole development by the use of a coupling numerical modelling approach. The 2D model uses a Finite Difference computer code associated with a Distinct Elements code to optimize the performances of both softwares. This allows an important decrease of computation time and the results computed are close of the experimental observations made before.

  11. Numerical methods for acquisition and analysis of vibration tests; Methodes numeriques d'acquisition et de depouillement d'essais aux vibrations

    Energy Technology Data Exchange (ETDEWEB)

    Badel, D.; Cocchi, G.; Oules, H. [Centre d' Etudes Scientifiques et Techniques d' Aquitaine (France). Centre d' Etudes Nucleaires

    1969-07-01

    The S.I.D.E.X. is a digital computer assisted facility for Data acquisition and Data processing. It is designed for sine wave or random environment tests, mechanical or acoustical vibrations, shock waves. The mathematical principles and the system configuration have been described in the CEA file nb R-3666. The present one describes the numerical methods and the programs available up to now. Some examples of results obtained are shown at the end. (authors) [French] Le systeme integre de depouillement pour l'experimentation S.I.D.E.X., a pour but d'effectuer les calibration, les acquisitions et les depouillements des essais aux vibrations sinusoidales ou aleatoires, mecaniques ou acoustiques et des essais de chocs. Les methodes mathematiques correspondantes et la configuration digitale employee ont ete decrites dans le rapport CEA nb CEA-R-3666. Le present rapport indique les methodes numeriques en vigueur et les programmes actuellement disponibles. Des exemples de resultats obtenus sont egalement presentes. (auteurs)

  12. Calculs Numeriques des Interactions Entre les Champs Electromagnetiques et les Tissus Biologiques

    Science.gov (United States)

    Mokhtech, Kamel-Eddine

    The understanding of electromagnetic field effects on health is a very acute problem nowadays. Indeed, the daily landscape is invaded by waves generated by affordable state-of-the-art equipment. It becomes urgent to improve the knowledge in order to ensure the safety of the users and the general public. At high frequencies two areas of concern can be distinguished: cellular telephony and wireless indoor communications. This dissertation is devoted to two aspects of the research in this field i.e. the numerical dosimetry and the biological experimentation. A new formulation for an expanding grid algorithm based upon the FDTD that can be applied, in particular, at high frequencies is presented. The energy deposition and the associated temperature rise in a model of the human eye due to a resonant dipole at frequencies of 840, 915, 1500 and 1800 MHz are then calculated. The duty cycle of each system is then introduced and its impact on temperature elevation is examined. Finally, a methodological approach to standard setting for portable transceivers is proposed. On the experimental aspect, a protocol has been elaborated and an experimentation to study athermal effects of electromagnetic fields at 9.3 GHz has been carried out. In particular, the importance of polarization has been examined.

  13. L'archivage a long terme de la maquette numerique trois-dimensionnelle annotee

    Science.gov (United States)

    Kheddouci, Fawzi

    The use of engineering drawings in the development of mechanical products, including the exchange of engineering data as well as for archiving, is common industry practice. Traditionally, paper has been the mean to deliver those needs. However, these practices have evolved in favour of computerized tools and methods for the creation, diffusion and preservation of data involved in the process of developing aeronautical products characterized by life cycles that can exceed 70 years. Therefore, it is necessary to redefine how to maintain this data in a context whereby engineering drawings are being replaced by the 3D annotated digital mock-up. This thesis addresses the issue of long-term archiving of 3D annotated digital mock-ups, which includes geometric and dimensional tolerances, as well as other notes and specifications, in compliance with the requirements formulated by the aviation industry including regulatory and legal requirements. First, we review the requirements imposed by the aviation industry in the context of long-term archiving of 3D annotated digital mock-ups. We then consider alternative solutions. We begin by identifying the theoretical approach behind the choice of a conceptual model for digital long-term archiving. Then we evaluate, among the proposed alternatives, an archiving format that will guarantee the preservation of the integrity of the 3D annotated model (geometry, tolerances and other metadata) and its sustainability. The evaluation of 3D PDF PRC as a potential archiving format is carried out on a sample of 185 3D CATIA V5 models (parts and assemblies) provided by industrial partners. This evaluation is guided by a set of criteria including the transfer of geometry, 3D annotations, views, captures and parts positioning in assembly. The results indicate that maintaining the exact geometry is done successfully when transferring CATIA V5 models to 3D PDF PRC. Concerning the transfer of 3D annotations, we observed degradation associated with

  14. Simulation numerique de l'accretion de glace sur une pale d'eolienne

    Science.gov (United States)

    Fernando, Villalpando

    The wind energy industry is growing steadily, and an excellent place for the construction of wind farms is northern Quebec. This region has huge wind energy production potential, as the cold temperatures increase air density and with it the available wind energy. However, some issues associated with arctic climates cause production losses on wind farms. Icing conditions occur frequently, as high air humidity and freezing temperatures cause ice to build up on the blades, resulting in wind turbines operating suboptimally. One of the negative consequences of ice accretion is degradation of the blade's aerodynamics, in the form of a decrease in lift and an increase in drag. Also, the ice grows unevenly, which unbalances the blades and induces vibration. This reduces the expected life of some of the turbine components. If the ice accretion continues, the ice can reach a mass that endangers the wind turbine structure, and operation must be suspended in order to prevent mechanical failure. To evaluate the impact of ice on the profits of wind farms, it is important to understand how ice builds up and how much it can affect blade aerodynamics. In response, researchers in the wind energy field have attempted to simulate ice accretion on airfoils in refrigerated wind tunnels. Unfortunately, this is an expensive endeavor, and researchers' budgets are limited. However, ice accretion can be simulated more cost-effectively and with fewer limitations on airfoil size and air speed using numerical methods. Numerical simulation is an approach that can help researchers acquire knowledge in the field of wind energy more quickly. For years, the aviation industry has invested time and money developing computer codes to simulate ice accretion on aircraft wings. Nearly all these codes are restricted to use by aircraft developers, and so they are not accessible to researchers in the wind engineering field. Moreover, these codes have been developed to meet aeronautical industry

  15. Modeling and numerical study of two phase flow; Modelisation et etude numerique d'ecoulements diphasiques: 1- Modelisation d'un ecoulement homogene equilibre 2- Modelisation des collisions entre gouttelettes a l'aide d'un modele simplifie de type BGK

    Energy Technology Data Exchange (ETDEWEB)

    Champmartin, A.

    2011-02-28

    suivre une vitesse relative entre les deux phases et de prendre en compte deux vitesses) et sont supposees 'a l'equilibre en temperature et pression. Cette partie du manuscrit est composee de la derivation des equations, de l'ecriture d'un schema numerique associe a ce jeu d'equations, d'une etude d'ordre de ce schema ainsi que de simulations. Une etude mathematique de ce modele (hyperbolicite dans un cadre simplifie, stabilite du systeme lineaire autour d'un etat constant) a ete realisee dans un cadre ou le gaz est suppose barotrope. La seconde partie de ce manuscrit est consacree a la modelisation de l'effet de collisions inelastiques sur les gouttelettes lorsque l'on se place a un temps de simulation beaucoup plus court, pour lequel les gouttelettes ne peuvent plus etre vues comme un fluide. Pour modeliser ces collisions, on construit un modele simplifie (moins couteux en temps) de type BGK permettant de reproduire le comportement en temps de certains moments sur les gouttelettes. Ces moments sont choisis pour etre representatifs de l'effet des collisions sur ces gouttelettes, a savoir une thermalisation en vitesse et energie. Ce modele est discretise avec une methode particulaire et des resultats numeriques sont donnes en comparaison avec ceux obtenus avec un modele resolvant directement l'equation de Boltzmann homogene. (auteur)

  16. Etude de la transmission sonore a travers un protecteur de type "coquilles" : modelisation numerique et validation experimentale

    Science.gov (United States)

    Boyer, Sylvain

    On estime que sur les 3,7 millions des travailleurs au Quebec, plus de 500 000 sont exposes quotidiennement a des niveaux de bruits pouvant causer des lesions de l'appareil auditif. Lorsqu'il n'est pas possible de diminuer le niveau de bruit environnant, en modifiant les sources de bruits, ou en limitant la propagation du son, le port de protecteurs auditifs individualises, telles que les coquilles, demeure l'ultime solution. Bien que vue comme une solution a court terme, elle est communement employee, du fait de son caractere peu dispendieux, de sa facilite d'implantation et de son adaptabilite a la plupart des operations en environnement bruyant. Cependant les protecteurs auditifs peuvent etre a la fois inadaptes aux travailleurs et a leur environnement et inconfortables ce qui limite leur temps de port, reduisant leur protection effective. Afin de palier a ces difficultes, un projet de recherche sur la protection auditive intitule : " Developpement d'outils et de methodes pour ameliorer et mieux evaluer la protection auditive individuelle des travailleur ", a ete mis sur pied en 2010, associant l'Ecole de technologie superieure (ETS) et l'Institut de recherche Robert-Sauve en sante et en securite du travail (IRSST). S'inscrivant dans ce programme de recherche, le present travail de doctorat s'interesse specifiquement a la protection auditive au moyen de protecteurs auditifs " passifs " de type coquille, dont l'usage presente trois problematiques specifiques presentees dans les paragraphes suivants. La premiere problematique specifique concerne l'inconfort cause par exemple par la pression statique induite par la force de serrage de l'arceau, qui peut reduire le temps de port recommande pour limiter l'exposition au bruit. Il convient alors de pouvoir donner a l'utilisateur un protecteur confortable, adapte a son environnement de travail et a son activite. La seconde problematique specifique est l'evaluation de la protection reelle apportee par le protecteur. La

  17. On the numerical simulation of uncertain parameters in a radionuclide transport model; Modelisation numerique de parametres incertains associes a un modele de transport de radionucleides

    Energy Technology Data Exchange (ETDEWEB)

    Diaz Moreno, J.M.; Ortegon Gallego, F. [Universidad de Cadiz, Dept. de Matematicas, CASEM (Spain); Lazaar, S. [Universite AbdelMalek Essaadi, Ecole Nationale des Sciences Appliquees, Dept. de Mathematiques et Informatique, Tanger Principale (Morocco)

    2007-10-15

    We study a fast algorithm to generate random fields which represent the uncertain parameters in a transport model of radionuclides in the geosphere. This algorithm has been introduced by Mikhailov and is based on a procedure known as Palm process. It can then be applied in a Monte Carlo method in the probabilistic risk assessment of high-level radioactive waste disposal in deep formation. We use this algorithm in order to compute the retardation factor appearing in the radionuclide migration model and we compare the CPU time corresponding to this procedure versus a classical spectral method. (authors)

  18. Study of problems arising from the use of thermal neutron detectors in a pulsed regime. Application to the development of a digital transferometer adapted to receive signals from these detectors; Etude des problemes poses par l'utilisation des detecteurs de neutrons thermiques fonctionnant en regime impulsionnel. Application a la realisation d'un transferometre numerique adapte aux signaux fournis par ces detecteurs

    Energy Technology Data Exchange (ETDEWEB)

    Le Tilly, Y. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1966-12-01

    The instantaneous value of the counting rate of the pulses given by a fission detector settled in a reactor follows the neutron flux, but it is shown that the counter adds a white noise to the measured signal. This report deals with some possibilities of on line numerical handling afforded by this kind of signals. One considers first the influence of a by N numerical divider and one shows that, acting like a quantifier, it adds to the signal a white noise with the power N{sup 2}/{sub 12}. One, studies afterwards the principle of a digital filter aimed to Fourier analyse the signal. The realization of this device is described. It can be used in transfer function measurements at frequencies below 125 kHz. Some examples of experiments performed with this apparatus are presented. One discusses finally the design, according to the same principle, of a power spectral density analyser in the frequency range 0,01 - 10 000 Hz for random signal of the same kind. (author) [French] La valeur instantanee de la frequence de recurrence des impulsions issues d'un detecteur a fission place dans un reacteur est proportionnelle au flux neutronique. Apres avoir montre que le detecteur ajoute un bruit blanc au signal mesure, on etudie clans ce rapport certaines possibilites de traitement numerique en temps reel offertes par ce type de signaux. On examine d'abord l'influence d'un diviseur numerique par N, et l'on montre que son action, semblable a une quantification, ajoute au signal un bruit blanc de puissance N{sup 2}/{sub 12}. On, etudie ensuite le principe d'un filtre numerique destine a effectuer l'analyse de Fourier du signal, et l'on decrit la realisation de cet appareil qui peut etre utilise pour mesurer des fonctions de transfert a une frequence quelconque inferieure a 10 kHz. Des exemples de mesures faites avec cet appareil sont presentes. On discute enfin la possibilite de realiser suivant le meme principe un analyseur de densite

  19. Mod\\'elisation num\\'erique des processus de transport des s\\'ediments et de l'\\'evolution des fonds

    CERN Document Server

    Cherif, El-Amine; Ouahsine, Abdellatif; Sergent, Philippe

    2011-01-01

    We propose a new mixing length profile, based on an extension of von K\\'arm\\'an similarity hypothesis, as well as the associated mixing velocity profile. This profile was compared with other profiles and was tested on three academic and experimental cases. The validation of the model was made from a set of reference examples and concerns the erosion of a bottom of sand in a uniform flow, and the filling of an extraction pit resulting from the tests presented in the European project SANDPIT. -- On propose un nouveau profil de longueur de m\\'elange lm (z), bas\\'e sur une extension de l'hypoth\\`ese de similitude de von K\\'arm\\'an, ainsi que le profil de vitesse de m\\'elange associ\\'e. Ce profil a \\'et\\'e compar\\'e \\`a d'autres profils et test\\'e sur trois cas test acad\\'emiques et exp\\'erimentaux. La validation du mod\\`ele a \\'et\\'e effectu\\'ee \\`a partir d'un ensemble d'exemples de r\\'ef\\'erences et concernent l'\\'erosion d'un fond de sable \\'erodable dans un \\'ecoulement uniforme en canal, et le remplissage d'...

  20. Design and use of numerical anatomical atlases for radiotherapy; Creation et utilisation d'atlas anatomiques numeriques pour la radiotherapie

    Energy Technology Data Exchange (ETDEWEB)

    Commowick, O

    2007-02-15

    The main objective of this thesis is to provide radio-oncology specialists with automatic tools for delineating organs at risk of a patient undergoing a radiotherapy treatment of cerebral or head and neck tumors. To achieve this goal, we use an anatomical atlas, i.e. a representative anatomy associated to a clinical image representing it. The registration of this atlas allows us to segment automatically the patient structures and to accelerate this process. Contributions in this method are presented on three axes. First, we want to obtain a registration method which is as independent as possible from the setting of its parameters. This setting, done by the clinician, indeed needs to be minimal while guaranteeing a robust result. We therefore propose registration methods allowing a better control of the obtained transformation, using rejection techniques of inadequate matching or locally affine transformations. The second axis is dedicated to the consideration of structures associated with the presence of the tumor. These structures, not present in the atlas, indeed lead to local errors in the atlas-based segmentation. We therefore propose methods to delineate these structures and take them into account in the registration. Finally, we present the construction of an anatomical atlas of the head and neck region and its evaluation on a database of patients. We show in this part the feasibility of the use of an atlas for this region, as well as a simple method to evaluate the registration methods used to build an atlas. All this research work has been implemented in a commercial software (Imago from DOSIsoft), allowing us to validate our results in clinical conditions. (author)

  1. Instabilities in numerical solutions to Fredholm and Volterra integral equations of the first kind. Resolution by Tchebycheff polynomials. Application to photonuclear cross-sections; Instabilite des solutions numeriques d'equations integrales de Fredholm et Volterra de premiere espece. Resolution par les polynomes de Tchebycheff. Application aux sections efficaces photonucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Moriceau, Y. [Commissariat a l' Energie Atomique, Centre d' Etudes de Limeil, 94 - Villeneuve-Saint-Georges (France)

    1968-03-01

    It is well known, if not well explained, that photo cross-sections curves depend on numerical resolution; as well as many other physical solutions from integral equations of the first kind, they are oscillating. In the first part of this report, a typical example points out how oscillations are growing. In the second part, a new method is explained yielding a smooth resolution. From experimental data on equidistant intervals, we build functions expanded in Tchebycheff polynomials; the solution is of this kind. Then, the third part points out that semi-analytical resolutions of this problem are illusive. (author) [French] C'est un fait reconnu mais mal explique, que les courbes de sections efficaces photonucleaires dependent de la resolution numerique adoptee. Beaucoup d'autres solutions physiques extraites d'une equation integrale de 1ere espece sont dans ce cas; elles sont arbitraires et oscillatoires. Dans la 1ere partie de ce rapport, on montre, dans un cas particulier typique, comment se forment les oscillations. Dans la 2eme partie, on presente une methode originale qui permet d'obtenir une resolution exempte d'oscillations. A partir de donnees experimentales a intervalles equidistants, on construit des fonctions developpees en polynomes de Tchebycheff; la solution est de ce type. Enfin, on montre dans la 3eme partie que les resolutions semi-analytiques de ce probleme sont illusoires. (auteur)

  2. Optimisation de parametres de la procedure geomatique d'extraction des caracteristiques hydrologiques d'un bassin versant a partir d'un modele numerique d'altitude

    Science.gov (United States)

    Quentin, Emmanuelle

    1999-11-01

    Modelling of water terrestrial superficial runoff, under the gravity action, is very useful in environmental sciences. Using a raster geographic information system (GIS), it is actually possible to generate the gridded waterway network on a watershed. The most frequently used drainage algorithm identifies the flow direction (aspect) from each cell to one of the eight adjacent cells (8D) according to the steepest elevation gradient. This drainage pattern allows the generation of the hydrographic network and subwatersheds. The basic input data is a digital elevation model (DEM), extracted from elevation contours and rasterised according to a grid cell size. The vectorial terrain network constitutes the only reference data needed. To control the hydrographic tree density, a minimal drainage area generating perennial streams has to be adjusted; but the error associated with the cartographic results can not be explicitly calculated owing to the hierarchical structure of the drainage algorithm. Classical Euclidean distance operations available in GIS are not adapted to quantify the deviation between the reference and the synthetic networks. This particular application requires the use of a drainage distance based on the flow path. Such concept allows the establishment of a unique error estimation that quantifies the spatial agreement between the generated and the reference networks, reflecting the accuracy of the drainage scheme from which all other hydrologic features are extracted. This optimisation technique has been tested on the Boyer River watershed located 25 km south-east of Quebec city and covering an area of approximately 220 km2. The 8D drainage algorithm used, which has been adapted and completed, allows for the consideration of low relief characteristics where elevations range from 275 m upstream to 10 m at the outlet in the Saint-Lawrence River. The reference DEM has been generated by interpolation of the elevation isolines available on the 1:20 000

  3. Numerical and experimental study of the beam dynamics of CANDELA photo-injector and associated instrumentation; Etude numerique et experimentale de la dynamique du faisceau du photo-injecteur CANDELA et instrumentation associee

    Energy Technology Data Exchange (ETDEWEB)

    Devanz, Guillaume [Paris-6 Univ., 95 Paris (France)

    1999-03-04

    Laser triggered radiofrequency guns are the most luminous electron sources allowing to reach the performances requested by highly demanding applications like the e{sup +}/e{sup -}linear colliders and the short wave free electron lasers. CANDELA is a band S photo-injector triggered by a sub-picosecond laser. It allows reaching peak currents of hundred of amperes at average energies higher than 2 MeV. The original concept of two accelerating cavities aims at minimizing the transverse and longitudinal emittances following the Gao's principles. From practical reasons the operating parameters, particularly the laser pulse duration, do not correspond to those considered in the design. Hence, numerical simulations were performed to evaluate the gun's performances in experimental environment. The study of a stabile injector operation resulted in evolutions with consequences in the phase control systems implying the laser and the HF (Hyper Frequency) source. The beam transverse and longitudinal characteristics have been measured as a function of the main parameters i.e., the beam charge and the phase shift between the laser and the HF wave. Measurements of the transverse emittance energy dispersion and wave packed duration are presented for several injector configurations. The systems of existing beam measurements have been studied to determine the resolution and the experimental conditions to fulfill, in order to suggest improvements for the CANDELA beam. The experiments with the beam have been compared with numerical simulations. Agreement was obtained within wide ranges of parameters for most of the characteristic beam quantities.

  4. Modelling and numerical simulation of two-phase flows using the two-fluid two-pressure approach; Modelisation et simulation numerique des ecoulements diphasiques par une approche bifluide a deux pressions

    Energy Technology Data Exchange (ETDEWEB)

    Guillemaud, V

    2007-03-15

    This thesis is devoted to the modelling and numerical simulation of liquid-vapor flows. In order to describe these phase transition flows, a two-fluid two-pressure approach is considered. This description of the liquid-vapor mixing is associated to the seven-equation model introduced by Baer and Nunziato. This work investigates the properties of this model in order to simulate the phase transition flows occurring in nuclear engineering. First, a theoretical thermodynamic framework is constructed to describe the liquid-vapor mixing. Provided with this framework, various modelling choices are suggested for the interaction terms between the phases. These closure laws comply with an entropy inequality. The mathematical properties of this model are thereafter examined. The convective part is associated to a nonconservative hyperbolic system. First, we focus on the definition of its weak solutions. Several flow regimes for the two-phase mixing derive from this analysis. Such regimes for the two-phase flows are analogous to the torrential and fluvial regimes for the shallow-water equations. Furthermore, we establish the linear and nonlinear stabilities of the liquid-vapor equilibrium. Finally, the implementation of a turbulence model and the introduction of a reconstruction process for the interfacial area are investigated in order to refine the description of the interfacial transfers. Using a fractional step approach, a Finite Volume method is at last constructed to simulate this model. First, various nonconservative adaptations of standard Riemann solvers are developed to approach the convective part. Unlike the classic nonconservative framework, these schemes converge towards the same solution. Furthermore, a new relaxation scheme is proposed to approach the interfacial transfers. Provided with these schemes, the whole numerical method preserves the liquid-vapor equilibria. Using this numerical method, a careful comparison between the one- and two-pressure two

  5. Development and testing of a fast digital electronic system for ion identification and spectroscopy; Etude et realisation d'une chaine d'instrumentation numerique rapide pour l'identification des ions

    Energy Technology Data Exchange (ETDEWEB)

    Legou, Th

    2002-02-01

    This report deals with a fast digital electronic system developed for ion identification and spectroscopy. The system, called IRIS, has been conceived for the super heavy element research program: FUSION. In order to observe a super heavy element, the energy of the compound nucleus implanted in a silicon detector must be measured, and the alpha decay also registered. The associated electronics must therefore handle a very wide range of energies and also exhibit a small recovery time after the implantation of the compound nucleus. IRIS is connected to the output of a charge preamplifier. It digitizes the signal and then executes two digital signal processes: the first to detect the particle, and the second to determine the energy deposited in the silicon detector. The use of programmed processing allows for the adjustment of the digital processing parameters, as well as a choice of other digital signal processing procedures, depending the application. After having explained why a conventional electronic system cannot be used for the detection of super-heavy ions, IRIS' structure is detailed and a number of digital signal processing procedures are studied and tested. (author)

  6. Thermo-hydrodynamic and inductive modelling of a glass melt elaborated in cold inductive crucible; Modelisation numerique thermo-hydrodynamique et inductive d'une fonte verriere elaboree en creuset froid inductif

    Energy Technology Data Exchange (ETDEWEB)

    Sauvage, E

    2009-11-15

    Within the context of a search for a new vitrification process for nuclear wastes with a replacement of the presently used metallic pot by an inductive cold crucible, this research thesis deals with the numerical modelling of this technology. After having recalled the interest of nuclear waste vitrification, this report presents the new process based on the use of a cold crucible, describing principles and objectives of this method, and the characteristic physical phenomena associated with the flow and the thermodynamics of the glassy melt in such a crucible. It also recalls and comments the existing works on modelling. The main objective of this research is then to demonstrate the feasibility of 3D thermo-hydraulic and inductive simulations. He describes and analyses the glass physical properties (electrical properties, viscosity, thermal properties), the electromagnetic, hydrodynamic and thermal phenomena. He presents in detail the bubbling mixing modelling, reports 3D induction and fluid mechanical coupling calculations, and specific thermal investigations (radiating transfers, thermal limit conditions)

  7. Prediction by numerical modeling of the risk zone along a riverside exposed to a dam failure; Prevision par modelisation numerique de la zone de risque bordant un troncon de riviere subissant une rupture de barrage

    Energy Technology Data Exchange (ETDEWEB)

    Mahdi, T.F.

    2004-07-01

    The risk zone associated with the surge wave following dam failure is defined in this study using a newly developed methodology that incorporates the conventionally used maximum water levels, the sediment movement in the river bed and the possibility of bank failure. Although the risk zone is typically defined as the inundated area, extensive lateral erosion that causes landslides could also accompany the inundation. This study demonstrates that the stability of the riverbank (in terms of geotechnical considerations) can influence the delineation of the risk area. The combined disciplines of geotechnics and hydraulics can be used to follow the evolution of the riverbed and riverbanks during a flood event. This study also presents a structured methodology for the St. Venant shallow water wave equations which were used to determine the area likely to be flooded without taking into account sediment transport. It also discusses aspects of the sediment transport theory. Fluvial erosion and lateral bank failure are the basic physical processes responsible for bank retreat. The minimum energy dissipation rate theory is applied for fluvial erosion, while Bishop's modified method is used to analyze slope stability when evaluating lateral bank failures. A numerical modeling of flows over movable beds is presented along with a review of some of the available numerical models. A diagnostic phase that provides information needed to qualify the extent of the damage after a flood is also presented. Some of the numerical models to evaluate risk area were validated on a portion of the HaHa River which was affected in the 1996 Saguenay flood. The new methodology, applied to the Outaouais River at Notre Dame du Nord in Quebec, produces a risk area much greater than that obtained when only the inundated area is considered.

  8. Explicit dynamics for numerical simulation of crack propagation by the extended finite element method; Dynamique explicite pour la simulation numerique de propagation de fissure par la methode des elements finis etendus

    Energy Technology Data Exchange (ETDEWEB)

    Menouillard, T

    2007-09-15

    Computerized simulation is nowadays an integrating part of design and validation processes of mechanical structures. Simulation tools are more and more performing allowing a very acute description of the phenomena. Moreover, these tools are not limited to linear mechanics but are developed to describe more difficult behaviours as for instance structures damage which interests the safety domain. A dynamic or static load can thus lead to a damage, a crack and then a rupture of the structure. The fast dynamics allows to simulate 'fast' phenomena such as explosions, shocks and impacts on structure. The application domain is various. It concerns for instance the study of the lifetime and the accidents scenario of the nuclear reactor vessel. It is then very interesting, for fast dynamics codes, to be able to anticipate in a robust and stable way such phenomena: the assessment of damage in the structure and the simulation of crack propagation form an essential stake. The extended finite element method has the advantage to break away from mesh generation and from fields projection during the crack propagation. Effectively, crack is described kinematically by an appropriate strategy of enrichment of supplementary freedom degrees. Difficulties connecting the spatial discretization of this method with the temporal discretization of an explicit calculation scheme has then been revealed; these difficulties are the diagonal writing of the mass matrix and the associated stability time step. Here are presented two methods of mass matrix diagonalization based on the kinetic energy conservation, and studies of critical time steps for various enriched finite elements. The interest revealed here is that the time step is not more penalizing than those of the standard finite elements problem. Comparisons with numerical simulations on another code allow to validate the theoretical works. A crack propagation test in mixed mode has been exploited in order to verify the simulation

  9. Tokamak electron heat transport by direct numerical simulation of small scale turbulence; Transport de chaleur electronique dans un tokamak par simulation numerique directe d'une turbulence de petite echelle

    Energy Technology Data Exchange (ETDEWEB)

    Labit, B

    2002-10-01

    In a fusion machine, understanding plasma turbulence, which causes a degradation of the measured energy confinement time, would constitute a major progress in this field. In tokamaks, the measured ion and electron thermal conductivities are of comparable magnitude. The possible sources of turbulence are the temperature and density gradients occurring in a fusion plasma. Whereas the heat losses in the ion channel are reasonably well understood, the origin of the electron losses is more uncertain. In addition to the radial velocity associated to the fluctuations of the electric field, electrons are more affected than ions by the magnetic field fluctuations. In experiments, the confinement time can be conveniently expressed in terms of dimensionless parameters. Although still somewhat too imprecise, these scaling laws exhibit strong dependencies on the normalized pressure {beta} or the normalized Larmor radius, {rho}{sub *}. The present thesis assesses whether a tridimensional, electromagnetic, nonlinear fluid model of plasma turbulence driven by a specific instability can reproduce the dependence of the experimental electron heat losses on the dimensionless parameters {beta} and {rho}{sub *}. The investigated interchange instability is the Electron Temperature Gradient driven one (ETG). The model is built by using the set of Braginskii equations. The developed simulation code is global in the sense that a fixed heat flux is imposed at the inner boundary, leaving the gradients free to evolve. From the nonlinear simulations, we have put in light three characteristics for the ETG turbulence: the turbulent transport is essentially electrostatic; the potential and pressure fluctuations form radially elongated cells called streamers; the transport level is very low compared to the experimental values. The thermal transport dependence study has shown a very small role of the normalized pressure, which is in contradiction with the Ohkama's formula. On the other hand

  10. Contribution to the study of the behaviour of solid particles in a confined turbulent flow using direct numerical simulation; Contribution a l'etude du comportement de particules solides en ecoulement turbulent confine par simulation numerique directe

    Energy Technology Data Exchange (ETDEWEB)

    Rambaud, P.

    2001-11-01

    The theme of this numerical thesis is on the behavior of solid particles embedded in a non-homogeneous and non-isotropic turbulent gas flow as the one tacking place in a plane channel. The turbulence is generated through the direct numerical simulation of Navier-Stokes equations discretized by formally second order in time and space finite difference operators. This Eulerian vision of the incompressible gas flow is completed by a Lagrangian formulation allowing to follow solid particles. In this formulation, the considered forces are the non-linear drag and the Saffman lift both corrected for wall effects. Furthermore, depending on the test cases studied, particle bouncing forces on the wall, gravity or electrostatic forces are taken into account. A three-dimensional Hermitian interpolation highlight the special care spend on the determination of the fluid velocity at the solid particle location. The first code application is dedicated to solid particles dispersion inside an horizontal channel, or in a channel operated in a weightlessness state. The huge amount of data from the Lagrangian tracking is reduced to the integral times of the turbulence seen by the solid particles on their trajectories. Those times are crucial in Lagrangian methods associated with a low numerical cost compared with the ones used in the present study. Among those methods, the one based on Langevin type equations have the best potential to handle industrial type problems. Nevertheless, this method needs to rebuild the fluid velocity fluctuations seen by the solid particles on their trajectories. This technic is able to reproduce the crossing trajectory effect, the inertial effect and the continuity effect, only if the integral times of the turbulence seen are known. Till now, those times were known thanks to a semi-empirical correlation from direct numerical simulation in homogeneous and isotropic turbulence (Wang and Stock 1993). However, although these conditions, this correlation was

  11. Modelisation numerique et algebrique des joints labyrinthe des turbines francis

    Science.gov (United States)

    Bouderlique, Remi

    There are various types of hydraulic turbines. Regarding the operating conditions, geometries and technologies differ. Hydraulic seals are only used in Francis turbines, which are widely used. The role of hydraulic seals is not to be waterproof. Their main aim is to prevent contact between the rotating and static parts of the turbine. Although necessary, hydraulic seals create energetic losses : some fluid does not flow through the runner (leakage loss) and exerts a torque on the rotor (friction loss). In a context of constant progression towards still more efficient turbines, the optimization of each part of the turbine is necessary. Our study is a part of this research seeking to decrease the losses in turbines as much as possible. In order to understand fully the problem, and to ensure an optimal seal exists, an analytical study has been lead in the first place. It establishes the analytical expressions of the speeds, pressure, losses and optimal seal length for laminar flows in straight seals. Various tests were then lead with the ANSYS CFX solver in order to highlight aspects which necessitate a particular attention. For example, the issues of boundary conditions and dimensionless simulations were adressed. A CFD model has then been validated. The results of the experiences lead in the sixties by Dominion Engineering Works, which later became Andritz Hydro Limited, were used in this process. Even if all the tests were not useable, some of them were reproduced numerically. The CFD model which was used features SST turbulence modeling, 2D axisymmetric geometries, parabolic mesh distributions, smooth walls, and a outlet headloss based on the normal speed. For the various tests which were considered, the average discrepancy between numerical and experimental results is 6.5%. More than 60% of the discrepancies of those simulations are below the empirical uncertainty. That is why this model can be used for numerical experiences : as long as these experiences are in the design space, their result will be coherent with reality. An appropriate space-filling design of experiments was created using the software JMP, from SAS Institute. The numerical results of 34 tests have then been modeled statistically using a quadratic polynomial taking into account interactions between various factors. The response surface obtained this way was compared to experimental results. The average discrepancy was around 7.5%. The response surface is precise enough to get an accurate estimation of the experimental results. As no other experimental data is available, nothing proves that the numerical model, and the statistical model which was obtained thanks to it, will be valid outside the design space which was considered.

  12. ASSOCIATION INFORMATION

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Beijing Charity Association Beijing Charity Association (BCA), a non-profit mass organization, is willing to serve Beijing’s lowincome people and promote local reforms and development, in a bid to construct a harmonious society.

  13. Numerical and experimental investigation of industrial electrostatic precipitators; Etude numerique et experimentale d`electrofiltres industriels

    Energy Technology Data Exchange (ETDEWEB)

    Tochon, P.

    1997-10-17

    This work deals with electrostatic precipitators or ESP used for gas-solid particles separation. By means of a dust-controlled testing loop created and realised at the GRETh`s plate-form (Research Group on Heat Exchangers) and a numerical model developed during this work from TRIO software, the study of the performances of different ESP geometries has been carried out. Many electrical, hydraulic and particular parameters governing solid particles collection under ionised electric field have been identified, measured and modelled. The numerical model, ratified with experimental data obtained during this study and from literature, allows to describe local and global phenomena occurring in any geometries. Furthermore, parametric studies have been carried out in order to propose some optimised geometries. allowing to increase collection efficiencies. At least, on-site measurements with CETIAT (Centre Technique des Industries Aerauliques et Thermiques) allow to identify dust particles likely to be thrown out to the atmosphere, and troubles peculiar to large scales industrial plants. The numerical model has also been tested on these data. At the end of this study, an efficient dust-controlled experimental tool, PACIFIC loop, and a numerical simulation allowing ESP sizing are available. (author)

  14. PREDICTION NUMERIQUE DES PERTES SECONDAIRES EN BOUT D'AUBE D'UN COMPRESSEUR AXIAL

    Directory of Open Access Journals (Sweden)

    A MAOUGAL

    1999-12-01

    Full Text Available La performance des machines se fait en termes de coefficients de perte de pression et de rendement pour chaque étage. Ce travail rentre dans le cadre du (pre- design des turbomachines. Cette phase préliminaire est devenue indispensable dans le domaine de l’engineering, ce qui permet de donner une approche de la machine avant son dimensionnement, de réaliser un gain économique très important et d’avoir ainsi une idée exacte de ce qu’on veux réaliser.

  15. ESSAIS DE COMPRESSION SUR BARRES D'HOPKINSON : SIMULATION NUMERIQUE ET ETUDE EXPERIMENTALE

    OpenAIRE

    1988-01-01

    Le principe de fonctionnement du test de compression dynamique à l'aide de barres d'Hopkinson est connu depuis de nombreuses années, mais il reste toujours des incertitudes quant à l'interprétation des résultats obtenus par celle technique. Le but de cette étude est de montrer les limites de la méthode ainsi que quelques règles pour le choix de la géométrie des échantillons. Des simulations numériques effectuées à l'aide du code lagrangien hydro-dynamique HEMP ont permis de quantifier l'erreu...

  16. Turbomachinery Design Using CFD (La Conception des Turbomachines par l’Aerodynamique Numerique).

    Science.gov (United States)

    1994-05-01

    Dimensional Navier-Stokes Analyses and Experiments", ASME Journal of Turboma- chinery, Vol. 113, p 1 3 9 . Adamczyk, J. J., Celestina , M. L., Beach, T...Adamczyk J. J., Celestina M. L., Greitzer E. M. (1993). ity of 3D flows in compressors and turbines, including tip "The Role of Tip Clearance in High...last two decades, there are still some important aspects of turbomachinery design that CFD is not able to cope with Adamczyk, J. J., Celestina , M. L

  17. SIMULATION NUMERIQUE DES COUCHES CISAILLEES PLANES A GRAND RAPPORT INITIAL DE MASSE VOLUMIQUE

    OpenAIRE

    Silvani, Xavier

    2001-01-01

    There is a close analogy between the dynamics of primary atomization process in a two phase shear layer and the processes initiating the mixing transition in a monophase layer presenting the same shear: the primary instability and and the elongation of dense fluid "fingers" in the rapid fllow are analogous if the inlet veocity and the initial density ratio are conserved between both cases. Therefore, the primary atomization coincides with the turbulent mixing if the Reynolds number and the We...

  18. Contribution a la modelisation et simulation numerique de l ecoulement du sang dans l artere

    CERN Document Server

    Alla, H; Bensaid, M H

    2009-01-01

    Numerous are the questionings raised by medicine interventionnelle, concerning the hold in charge of the pathologies of the arterial partition (aneurysm, dissection, coarctation, atherosclerosis).for it we made the modeling and the numeric simulation of the blood flow in the renal artery taken by the Medical imagery. Geometry has been rebuilt from the medical pictures of angiography, angioscanner and IRM. While considering that blood like a fluid Newtonian and stationary flow. The results gotten in terms of the physical parameters as the velocity, the dynamic pressure is shown that the simplest case was enough to collect relevant data for the development of stenos or thrombosis in the arteries.

  19. Development of numerical methods for reactive transport; Developpement de methodes numeriques pour le transport reactif

    Energy Technology Data Exchange (ETDEWEB)

    Bouillard, N

    2006-12-15

    When a radioactive waste is stored in deep geological disposals, it is expected that the waste package will be damaged under water action (concrete leaching, iron corrosion). Then, to understand these damaging processes, chemical reactions and solutes transport are modelled. Numerical simulations of reactive transport can be done sequentially by the coupling of several codes. This is the case of the software platform ALLIANCES which is developed jointly with CEA, ANDRA and EDF. Stiff reactions like precipitation-dissolution are crucial for the radioactive waste storage applications, but standard sequential iterative approaches like Picard's fail in solving rapidly reactive transport simulations with such stiff reactions. In the first part of this work, we focus on a simplified precipitation and dissolution process: a system made up with one solid species and two aqueous species moving by diffusion is studied mathematically. It is assumed that a precipitation dissolution reaction occurs in between them, and it is modelled by a discontinuous kinetics law of unknown sign. By using monotonicity properties, the convergence of a finite volume scheme on admissible mesh is proved. Existence of a weak solution is obtained as a by-product of the convergence of the scheme. The second part is dedicated to coupling algorithms which improve Picard's method and can be easily used in an existing coupling code. By extending previous works, we propose a general and adaptable framework to solve nonlinear systems. Indeed by selecting special options, we can either recover well known methods, like nonlinear conjugate gradient methods, or design specific method. This algorithm has two main steps, a preconditioning one and an acceleration one. This algorithm is tested on several examples, some of them being rather academical and others being more realistic. We test it on the 'three species model'' example. Other reactive transport simulations use an external chemical code CHESS. For a realistic case of Uraninite leaching, accelerated Picard methods divide the CPU cost of standard Picard's by three and the number of iteration by five. (author)

  20. ETUDE BIBLIOGRAPHIQUE ET NUMERIQUE DES PHENOMENES DE TRANSPORT DANS LE BETON

    OpenAIRE

    DJELIL, Mohammed

    2012-01-01

    Une faible durabilité des structures en béton peut provoquer une ruine complète ou partielle des ouvrages. En fonction des conditions d’exposition, les différents mécanismes à la source des dégradations font très souvent intervenir un ou plusieurs phénomènes de transport. Une analyse bibliographique détaillée sur les propriétés physico-chimiques et microstructurales des matériaux cimentaires, puis, sur les différents phénomènes de transport, constitue le premier objectif de ce ...

  1. Approches experimentale et numerique de l'usinage a sec des composites carbone/epoxy

    OpenAIRE

    Iliescu, Daniel

    2008-01-01

    The research topic is a preliminary study for maximizing the dry machining of carbon/epoxy. The proposed study deals with understanding the mechanisms of damage tools. It aims to determine the parameters of the tribological interface tool-workpiece (forces, temperature, friction, roughness) and confront them with the tools wear. Cutting operations generate heat and strains, and cut surfaces are often affected by damages. A study based on experimental observation of the formation of the chip (...

  2. Staff Association

    CERN Multimedia

    Staff Association

    2014-01-01

    Remove of the staff association office   The Staff Association offices are going to be renovated during the coming four months, February to May 2014. The physical move from our current premises 64/R-002 to our temporary office in  510/R-010 will take place on Friday January 31st, so the Secretariat will be closed on that day. Hence, from Monday February 3rd until the end of May 2014 the Staff Association Secretariat will be located in 510/R-010 (entrance just across the CERN Printshop).    

  3. Etude aerodynamique d'un jet turbulent impactant une paroi concave

    Science.gov (United States)

    LeBlanc, Benoit

    , tridimensionnel. Les nombres de Reynolds utilises dans l'etude numerique, bases sur le diametre du jet lineaire observe, sont de Red = 3333 et 6667, consideres comme etant en transition vers la turbulence. Dans cette etude, un montage numerique est construit. Le maillage, le schema numerique, les conditions frontiere et la discretisation sont discutes et choisis. Les resultats sont ensuite valides avec des donnees turbulentes experimentales. En modelisation numerique de turbulence, les modeles de Moyennage Reynolds des Equations Naviers Stokes (RANS) presentent des difficultes avec des ecoulements instationnaires en regime transitionnel. La Simulation des Grandes Echelles (LES) presente une solution plus precise, mais au cout encore hors de portee pour cette etude. La methode employee pour cette etude est la Simulation des Tourbillons Detaches (DES), qui est un hybride des deux methodes (RANS et LES). Pour analyser la topologie de l'ecoulement, la decomposition des modes propres (POD) a ete egalement ete effectuee sur les resultats numeriques. L'etude a demontre d'abord le temps de calcul relativement eleve associe a des essais DES pour garder le nombre de Courant faible. Les resultats numeriques ont cependant reussi a reproduire correctement le basculement asynchrone observe dans les essais experimentaux. Le basculement observe semble etre cause par des effets transitionnels, ce qui expliquerait la difficulte des modeles RANS a correctement reproduire l'aerodynamique de l'ecoulement. L'ecoulement du jet, a son tour, est pour la plupart du temps tridimensionnel et turbulent sauf pour de courtes periodes de temps stable et independant de la troisieme dimension. L'etude topologique de l'ecoulement a egalement permit la reconaissances de structures principales sousjacentes qui etaient brouillees par la turbulence. Mots cles : jet impactant, paroi concave, turbulence, transitionnel, simulation des tourbillons detaches (DES), OpenFOAM.

  4. Alzheimer's Association

    Science.gov (United States)

    ... will not share your information. * Required. View archives. Alzheimer's impact is growing Alzheimer's disease is the sixth- ... Last Updated: Our vision is a world without Alzheimer's Formed in 1980, the Alzheimer's Association advances research ...

  5. ALS Association

    Science.gov (United States)

    ... ALS and their families in areas affected by Hurricane Harvey. Learn More The ALS Association Disaster Relief Fund ... ALS and their families in areas affected by Hurricane Harvey. Learn More Our Mission To discover treatments and ...

  6. Primitive Associations

    DEFF Research Database (Denmark)

    Ernst, Erik

    2007-01-01

    This position paper presents a very simple mechanism, primitive associations, and argues that this mechanism is worth careful consideration in connection with the kind of support for program correctness that grows out of mechanisms for ownership, controlled aliasing, sharing, escape analysis...

  7. Associational control

    DEFF Research Database (Denmark)

    Hvid, Helge Søndergaard; Lund, Henrik Lambrecht; Grosen, Sidsel Lond

    2010-01-01

    Over the last 30 years, the concept of control has had a central position in research into the psychological working environment. Control has been understood as individual autonomy and individual opportunities for development. This article examines whether the concept of control has the same key...... significance in the modern workplace which is simultaneously characterized by self-management and standardization. It is concluded that the concept of control remains important, but needs to evolve from its focus on the work of individuals to a focus on the associational aspects of work if it is to retain its...... critical potential. This conclusion is supported by case studies of four Danish banks....

  8. CHARGE Association

    Directory of Open Access Journals (Sweden)

    Semanti Chakraborty

    2012-01-01

    Full Text Available We present here a case of 17-year-old boy from Kolkata presenting with obesity, bilateral gynecomastia, mental retardation, and hypogonadotrophic hypogonadism. The patient weighed 70 kg and was of 153 cm height. Facial asymmetry (unilateral facial palsy, gynecomastia, decreased pubic and axillary hair, small penis, decreased right testicular volume, non-palpable left testis, and right-sided congenital inguinal hernia was present. The patient also had disc coloboma, convergent squint, microcornea, microphthalmia, pseudohypertelorism, low set ears, short neck, and choanalatresia. He had h/o VSD repaired with patch. Laboratory examination revealed haemoglobin 9.9 mg/dl, urea 24 mg/dl, creatinine 0.68 mg/dl. IGF1 77.80 ng/ml (decreased for age, GH <0.05 ng/ml, testosterone 0.25 ng/ml, FSH-0.95 ΅IU/ml, LH 0.60 ΅IU/ml. ACTH, 8:00 A.M cortisol, FT3, FT4, TSH, estradiol, DHEA-S, lipid profile, and LFT was within normal limits. Prolactin was elevated at 38.50 ng/ml. The patient′s karyotype was 46XY. Echocardiography revealed ventricularseptal defect closed with patch, grade 1 aortic regurgitation, and ejection fraction 67%. Ultrasound testis showed small right testis within scrotal sac and undescended left testis within left inguinal canal. CT scan paranasal sinuses revealed choanalatresia and deviation of nasal septum to the right. Sonomammography revealed bilateral proliferation of fibroglandular elements predominantly in subareoalar region of breasts. MRI of brain and pituitary region revealed markedly atrophic pituitary gland parenchyma with preserved infundibulum and hypothalamus and widened suprasellar cistern. The CHARGE association is an increasingly recognized non-random pattern of congenital anomalies comprising of coloboma, heart defect, choanal atresia, retarded growth and development, genital hypoplasia, ear abnormalities, and/or deafness. [1] These anomalies have a higher probability of occurring together. In this report, we have

  9. Double-grid numerical methods for the numerical simulation of poly-phase flows in porous media; Methodes numeriques de double maillage pour la simulation numerique des ecoulements polyphasiques dans les milieux poreux

    Energy Technology Data Exchange (ETDEWEB)

    Verdiere, S.

    1997-04-29

    Petroleum reservoirs are made of highly heterogeneous rocks. Simulations of these reservoirs result in geo-scientific works to integrate the data and knowledge about the field. Generally, the reservoir is represented on a very high resolution (HR) grid which can be composed of millions of cells. In order to run fluid flow simulations, it is necessary to reduce the number of cells. Thus, conventional method is to coarsen the grid and to obtain a lower resolution (LR) grid by doing up-scaling before the fluid flow simulation is done. The alternative we propose to classical method is to consider, for a coupled system pressure-saturation a specific discretization in time and space for each unknown. So, for a two phase problem, the principle is to solve the pressure equation over a LR grid and the saturation equation over a HR grid. In addition to the usual steps used in an IMPES scheme, it is necessary to allow the transfer of the results of the implicit resolution of the pressure equation form the LR o the HR Grid and calculate the averaged parameters necessary to the resolution of the pressure equation during the next time step by taking into account the evolution of the saturation. The validation of the Dual Mesh Method has been done for a two-phase problem both theoretically and practically. (author) 73 refs.

  10. Numerical simulation of two phase flows in heat exchangers; Simulation numerique des ecoulements diphasiques dans les echangeurs

    Energy Technology Data Exchange (ETDEWEB)

    Grandotto Biettoli, M

    2006-04-15

    The report presents globally the works done by the author in the thermohydraulic applied to nuclear reactors flows. It presents the studies done to the numerical simulation of the two phase flows in the steam generators and a finite element method to compute these flows. (author)

  11. Fracture num\\'erique chez les seniors du 4eme age. Observation d'une acculturation technique

    CERN Document Server

    Michel, Christine; Tarpin-Bernard, Franck

    2009-01-01

    Very old people accumulate the "handicaps": social, physical, psychological or cognitive. Various research thus developed to determine there waiting and needs and also to see the benefit possibly produced by technologies (called ?gerontechnology?) on their living conditions. The object of this article is to present the numerical service offer to very old perople and to see how it takes part in a social justice according to the definition of Rawls (principle of equal freedom, principle of equal opportunity in the access). The adoption, the use and the benefit of technology are analyzed in a theoretical way through a state of the art and in an experimental way through a qualitative and quantitative investigation carried out with a population of very old people. We propose to identify dynamic technological acceptance of old people according to the TAM'S (Technology Acceptance Model) of Davis adapted by (Hamner and Qazi, 2008).

  12. Computational and Experimental Assessment of Jets in Cross Flow (Evaluation Numerique et Experimentale des Jets dans des Courants Transversaux)

    Science.gov (United States)

    1993-11-01

    Italy Escuela Tecnica Superior Prof. Dr Ir J.L. van Ingen de Ingenieros Aeronauticos Dept. of Aerospace Engineering Departamento de Mecanica de...integration along the line of sight. Its use of molecular markers allows high spatial resolution measurements 2. INTRODUCTION with minimal alteration of the... molecular diffusion coefficient bivalves (animals with incurrent and excurrent hs siphon height above the boundary Presented at an AGARD Meeting on

  13. Complex transfers in porous media: some physical and numerical approaches; Transferts complexes en milieux poreux: quelques approches physiques et numeriques

    Energy Technology Data Exchange (ETDEWEB)

    Maugis, P

    2006-06-15

    The feasibility and safety of nuclear waste storage containers is studied. The thermodynamics of water/air flow is described and applied, via a simplified numerical model, to a simple experimental apparatus yielding heat pipe effect. The 2D influence of deterministic boundary conditions is important on kinematics and transport. Dispersivity depends on the nonuniform flow type and integrates the often marginal Gaussian part of plume spreading. A new algorithm, based on jump locality and recalibration, avoids the small bias induced by inter-cell diffusive jumps. Several algorithms modeling transport of decaying, soluble, sorbing, or precipitating species are compared. Stability and precision criteria are analyzed. Up-stream over-precipitation and negative down-stream concentrations are observed for high solubility contrasts. (author)

  14. Numerical modeling of transferred arc melting bath heating; Modelisation numerique du chauffage de bains par arc transfere

    Energy Technology Data Exchange (ETDEWEB)

    Bouvier, A. [Electricite de France, 77 - Moret sur Loing (France). Direction des Etudes et Recherches; Trenty, L.; Guillot, J.B. [Ecole Centrale de Paris, Laboratoire EM2C. CNRS, 92 - Chatenay-Malabry (France); Delalondre, C. [Electricite de France (EDF), 78 - Chatou (France). Direction des Etudes et Recherches

    1997-12-31

    This paper presents the modeling of a transferred electric arc inside a bath of melted metal. After a recall of the context of the study, the problem of the modeling, which involves magnetohydrodynamic coupling inside the arc and the bath, is described. The equations that govern the phenomena inside the arc and the bath are recalled and the approach used for the modeling of the anode region of the arc is explained using a 1-D sub-model. The conditions of connection between arc and bath calculations are explained and calculation results obtained with a 200 kW laboratory furnace geometry are presented. (J.S.) 8 refs.

  15. Verification and Validation Data for Computational Unsteady Aerodynamics (Donnees de verification et de valadation pour l’aerodynamique instationnaire numerique)

    Science.gov (United States)

    2007-11-02

    faciliter leur traitement et mise en œuvre, les données sont fournies sous une forme exploitable par une machine sur le CD-ROM qui accompagne ce rapport. Le...and Control 201 Surface Oscillations and Flutter by R.M. Bennett, R.C. Scott and C.D. Wieseman 8C. Benchmark Active Controls Technology (BACT) Wing CFD...Results 225 by D.M. Schuster and R.E. Bartels 9E. Test Cases for a Clipped Delta Wing with Pitching and Trailing-Edge Control 239 Surface Oscillations

  16. Critique du rapport signal \\`a bruit en communications num\\'eriques -- Questioning the signal to noise ratio in digital communications

    CERN Document Server

    Fliess, Michel

    2008-01-01

    The signal to noise ratio, which plays such an important r\\^ole in information theory, is shown to become pointless for digital communications where the demodulation is achieved via new fast estimation techniques. Operational calculus, differential algebra, noncommutative algebra and nonstandard analysis are the main mathematical tools.

  17. Experimental and numerical study of the mars pathfinder vehicle; Etude experimentale et numerique sur le mars pathfinder

    Energy Technology Data Exchange (ETDEWEB)

    Bur, R.; Benay, R.; Chanetz, B.; Galli, A.; Pot, T. [Office National d' Etudes et de Recherches Aerospatiales (ONERA), Dept. Fundamental and Experimental Aerodynamics, 92 - Chatillon (France); Hollis, B.; Moss, J. [Aerothermodynamics Branch, NASA Langley Research Center Hampton, Virginia (United States)

    2002-07-01

    An experimental and numerical study on the Mars Pathfinder aero-shell vehicle has been carried out in the framework of an agreement between ONERA and NASA. The experimental work was performed in the ONERA R5Ch hypersonic wind tunnel. Flow-field visualizations and heat-flux measurements along the model have been obtained. Numerical simulations have been performed at ONERA with the RANS solver NASCA and at NASA with a DSMC code. The flow-field structure is correctly reproduced by both computations. The location of the bow shock is well predicted, as well as the expansion waves emanating from the end of the fore-body cone. Both computations also predict the same extension of the separation bubble in the base flow region of the model. Measured and calculated heat-flux distributions along the model have been compared. Both computations give similar results, excepted on the prediction of the heat-flux level on the after-body cone. But computations over-predict the measured heat-flux values on the fore-body and the sting of the model: the value of the stagnation point is overestimated of 28% and the averaged sting level of 35%. (authors)

  18. Conception et evaluation d'une intervention didactique a propos des phases de la lune dans un planetarium numerique

    Science.gov (United States)

    Chastenay, Pierre

    Since the Quebec Education Program came into effect in 2001, Quebec classrooms have again been teaching astronomy. Unfortunately, schools are ill-equipped to teach complex astronomical concepts, most of which occur outside school hours and over long periods of time. Furthermore, many astronomical phenomena involve celestial objects travelling through three-dimensional space, which we cannot access from our geocentric point of view. The lunar phases, a concept prescribed in secondary cycle one, fall into that category. Fortunately, schools can count on support from the planetarium, a science museum dedicated to presenting ultra-realistic simulations of astronomical phenomena in fast time and at any hour of the day. But what type of planetarium will support schools? Recently, planetariums also underwent their own revolution: they switched from analogue to digital, replacing geocentric opto-mechanical projectors with video projectors that offer the possibility of travelling virtually through a completely immersive simulation of the three-dimensional Universe. Although research into planetarium education has focused little on this new paradigm, certain of its conclusions, based on the study of analogue planetariums, can help us develop a rewarding teaching intervention in these new digital simulators. But other sources of inspiration will be cited, primarily the teaching of science, which views learning no longer as the transfer of knowledge, but rather as the construction of knowledge by the learners themselves, with and against their initial conceptions. The conception and use of constructivist learning environments, of which the digital planetarium is a fine example, and the use of simulations in astronomy will complete our theoretical framework and lead to the conception of a teaching intervention focusing on the lunar phases in a digital planetarium and targeting students aged 12 to 14. This teaching intervention was initially tested as part of development research (didactic engineering) aimed at improving it, both theoretically and practically, through multiple iterations in its "natural" environment, in this case an inflatable digital planetarium six metres in diameter. We are presenting the results of our first iteration, completed with help from six children aged 12 to 14 (four boys and two girls) whose conceptions about the lunar phases were noted before, during and after the intervention through group interviews, questionnaires, group exercises and recordings of the interventions throughout the activity. The evaluation was essentially qualitative, based on the traces obtained throughout the session, in particular within the planetarium itself. This material was then analyzed to validate the theoretical concepts that led to the conception of the teaching intervention and also to reveal possible ways to improve the intervention. We noted that the intervention indeed changed most participants' conceptions about the lunar phases, but also identified ways to boost its effectiveness in the future.

  19. Metal-clad sub-stations - trends towards digital instrumentation; Poste sous enveloppe metallique: vers des travees numeriques

    Energy Technology Data Exchange (ETDEWEB)

    Mulatier, D.; Gens, S. [Schneider Electric S.A., 92 - Boulogne-Billancourt (France)

    2000-02-01

    Developments in technology are enabling the installation of new types of digital and low level analogue sensors in metal-clad sub-stations. The parameters measured by these sensors include voltage, current, SF{sub 6} density and switch positions. These new sensors offer several advantages for the operator, including increased reliability of the data acquisition chain and simple customization to take account of changing requirements. They also lead to a reduction in costs, space requirements and cabling. (authors)

  20. Modeling and numerical study of transfers in fissured environments; Modelisation et etude numerique des transferts en milieux fissures

    Energy Technology Data Exchange (ETDEWEB)

    Granet, S.

    2000-01-28

    Oil recovery from fractured reservoirs plays a very important role in the petroleum industry. Some of the world most productive oil fields are located in naturally fractured reservoirs. Modelling flow in such a fracture network is a very complex problem. This is conventionally done using a specific idealized model. This model is based on the Warren and Root representation and on a dual porosity, dual permeability approach. A simplified formulation of matrix-fracture fluid transfers uses a pseudo-steady-state transfer equation involving a constant exchange coefficient. Such a choice is one of the main difficulties of this approach. To get a better understanding of the simplifications involved in the dual porosity approach a reference model must be available. To obtain such a fine description, we have developed a new methodology. This technique called 'the fissure element methodology' is based on a specific gridding of the fractured medium. The fissure network is gridded with linear elements coupled with an unstructured triangular grid of matrix. An appropriate finite volume scheme has been developed to provide a good description of the flow. The numerical development of is precisely described. A simulator has been developed using this method. Several simulations have been realised. Comparisons have been done with different dual-porosity dual-permeability models. A reflexion concerning the choice of the exchange coefficient used in the dual porosity model is then proposed. This new tool has permit to have a better understanding of the production mechanisms of a complex fractured reservoir. (author)

  1. Enhancement of compact heat exchanger fins: numerical and experimental study; Optimisation des echangeurs compacts a ailettes: etude numerique et experimentale

    Energy Technology Data Exchange (ETDEWEB)

    Michel, F.

    2003-10-01

    This work concerns plate fins compact heat exchangers. These compact devices (C > 700 m2/m3) reduce bulk and weight due to large surfaces for heat transfer. These exchangers, widely used in automotive systems, cryogenics and aeronautics, are currently studied with empirical correlations. So, this limits the evolution of fins in compact heat exchangers. We propose a numerical methodology for designing and enhancing Offset Strip Fin (OSF) geometries. Numerical models and methods have been validated to correctly predict thermohydraulics in Offset Strip Fin heat exchangers. We have validated simulations with data from the literature but also with two experimental devices made for this thesis. Local and global temperature and velocity measurements have been realised in geometries near Offset Strip Fins. Hot wire and cold wire anemometry and Laser Doppler Anemometry (LDA) have been used to obtained validation data. Finally, the validated numerical simulations have been used to enhance geometries of fins and to give innovating geometries. (author)

  2. Contributions to reinforced concrete structures numerical simulations; Contributions a la simulation numerique de structures en beton arme

    Energy Technology Data Exchange (ETDEWEB)

    Badel, P.B

    2001-07-15

    In order to be able to carry out simulations of reinforced concrete structures, it is necessary to know two aspects: the behaviour laws have to reflect the complex behaviour of concrete and a numerical environment has to be developed in order to avoid to the user difficulties due to the softening nature of the behaviour. This work deals with these two subjects. After an accurate estimation of two behaviour models (micro-plan and mesoscopic models), two damage models (the first one using a scalar variable, the other one a tensorial damage of the 2 order) are proposed. These two models belong to the framework of generalized standard materials, which renders their numerical integration easy and efficient. A method of load control is developed in order to make easier the convergence of the calculations. At last, simulations of industrial structures illustrate the efficiency of the method. (O.M.)

  3. Direct numerical simulation of granular flows with fluid; Simulation numerique directe d'ecoulements granulaires en presence de fluide

    Energy Technology Data Exchange (ETDEWEB)

    Komiwes, V.

    1999-09-01

    Numerical models applied to simulation of granular flow with fluid are developed. The physical model selected to describe particles flow is a discrete approach. Particle trajectories are calculated by the Newton law and collision is describe by a soft-sphere approach. The fluid flow is modelled by Navier-Stokes equations. The modelling of the momentum transfer depends on the resolution scale: for a scale of the order of the particle diameter, it is modelled by a drag-law and for a scale smaller than the particle diameter, it is directly calculated by stress tensor computation around particles. The direct model is used to find representative elementary volume and prove the local character of the Ergun's law. This application shows the numerical (mesh size), physical (Reynolds number) and computational (CPU time and memory consumptions) limitations. The drag law model and the direct model are validated with analytical and empirical solutions and compared. For the two models, the CPU time and the memory consumptions are discussed. The drag law model is applied to the simulation of gas-solid dense fluidized-beds. In the case of uniform gas distribution, the fluidized-bed simulation heights are compared to experimental data for particle of group A and B of the Geldart classification. (author)

  4. Numerical modelling of steel arc welding; Modelisation numerique du soudage a l'arc des aciers

    Energy Technology Data Exchange (ETDEWEB)

    Hamide, M

    2008-07-15

    Welding is a highly used assembly technique. Welding simulation software would give access to residual stresses and information about the weld's microstructure, in order to evaluate the mechanical resistance of a weld. It would also permit to evaluate the process feasibility when complex geometrical components are to be made, and to optimize the welding sequences in order to minimize defects. This work deals with the numerical modelling of arc welding process of steels. After describing the industrial context and the state of art, the models implemented in TransWeld (software developed at CEMEF) are presented. The set of macroscopic equations is followed by a discussion on their numerical implementation. Then, the theory of re-meshing and our adaptive anisotropic re-meshing strategy are explained. Two welding metal addition techniques are investigated and are compared in terms of the joint size and transient temperature and stresses. The accuracy of the finite element model is evaluated based on experimental results and the results of the analytical solution. Comparative analysis between experimental and numerical results allows the assessment of the ability of the numerical code to predict the thermomechanical and metallurgical response of the welded structure. The models limitations and the phenomena identified during this study are finally discussed and permit to define interesting orientations for future developments. (author)

  5. Contribution to the numerical modeling of inertial confinement fusion; Contribution a la modelisation numerique de la fusion par confinement inertiel

    Energy Technology Data Exchange (ETDEWEB)

    Maire, P.H.

    2011-02-15

    This work was realized by writing the CHIC code, which is a software for designing and restoring experience in the field of inertial confinement fusion. The theoretical model describing the implosion of a laser target is a system of partial differential equations in the center of which is the Euler equations written in Lagrangian formalism, coupled with diffusion equations modeling the nonlinear transport of energy by electrons and photons. After a brief review of the physical context, we describe two novel methods which constitute the backbone of the CHIC code. These are 2 high-order finite volume schemes respectively dedicated to solving the equations of Lagrangian hydrodynamics and the anisotropic diffusion equations on bi-dimensional unstructured grids. The first scheme, called EUCCLHYD (Explicit Unstructured Lagrangian Hydrodynamics), solves the equations of gas dynamics on a moving mesh that moves at the speed of light. It is obtained from a general formalism based on the concept of sub-cell forces. In this context, the numerical fluxes are expressed in terms of the sub-cell force and the nodal velocity. Their determination is based on 3 basic principles: geometric compatibility between the movement of nodes and the volume change of mesh (geometric conservation law), compatibility with the second law of thermodynamics and conservation of total energy and momentum. The high-order extension is performed using a method based on solving a generalized Riemann problem in the acoustic approximation. The second scheme, called CCLAD (Cell-Centered Lagrangian Diffusion), solves the anisotropic heat equation. The corresponding discretization relies on a discrete variational formulation based on the sub-cell that allows to build a multipoint approximation of heat flux. This high-order discretization makes possible the resolution of the equations of anisotropic diffusion with satisfactory accuracy on highly distorted Lagrangian meshes. (author)

  6. Computational Aerodynamics Based on the Euler Equations (L’aerodynamique Numerique a Partir des Equations d’Euler)

    Science.gov (United States)

    1994-01-01

    dquations d’Euler) Edited by * S J.W. SLOOFF National Aerospace Laboratory NLR Anthony Fokkerweg 2 1059 CM Amsterdam Netherlands Dr. W. SCHMIDT Air Vehicle...CHAKRAVARTHY. S. R., RIBA , W.* * T.. BYERLY. J. and DRESSER. H. S.. "Multi-Zone Euler 41. DESLANDES R.M.. "Theoretisebe bestimmung der Marching Technique

  7. Methodologie de conception numerique d'un ventilateur helico-centrifuge basee sur l'emploi du calcul meridien

    Science.gov (United States)

    Lallier-Daniels, Dominic

    La conception de ventilateurs est souvent basée sur une méthodologie « essais/erreurs » d'amélioration de géométries existantes ainsi que sur l'expérience de design et les résultats expérimentaux cumulés par les entreprises. Cependant, cette méthodologie peut se révéler coûteuse en cas d'échec; même en cas de succès, des améliorations significatives en performance sont souvent difficiles, voire impossibles à obtenir. Le projet présent propose le développement et la validation d'une méthodologie de conception basée sur l'emploi du calcul méridien pour la conception préliminaire de turbomachines hélico-centrifuges (ou flux-mixte) et l'utilisation du calcul numérique d'écoulement fluides (CFD) pour la conception détaillée. La méthode de calcul méridien à la base du processus de conception proposé est d'abord présentée. Dans un premier temps, le cadre théorique est développé. Le calcul méridien demeurant fondamentalement un processus itératif, le processus de calcul est également présenté, incluant les méthodes numériques de calcul employée pour la résolution des équations fondamentales. Une validation du code méridien écrit dans le cadre du projet de maîtrise face à un algorithme de calcul méridien développé par l'auteur de la méthode ainsi qu'à des résultats de simulation numérique sur un code commercial est également réalisée. La méthodologie de conception de turbomachines développée dans le cadre de l'étude est ensuite présentée sous la forme d'une étude de cas pour un ventilateur hélico-centrifuge basé sur des spécifications fournies par le partenaire industriel Venmar. La méthodologie se divise en trois étapes: le calcul méridien est employé pour le pré-dimensionnement, suivi de simulations 2D de grilles d'aubes pour la conception détaillée des pales et finalement d'une analyse numérique 3D pour la validation et l'optimisation fine de la géométrie. Les résultats de calcul méridien sont en outre comparés aux résultats de simulation pour la géométrie 3D afin de valider l'emploi du calcul méridien comme outil de prédimensionnement. Mots-clés Turbomachines hélico-centrifuges, Calcul méridien, Simulation numérique d'écoulement fluide, Conception numérique de turbomachines.

  8. Numerical simulation of crack propagation in pressure equipments; Simulation numerique de la propagation de fissures dans les structures sous pression

    Energy Technology Data Exchange (ETDEWEB)

    Le Grognec, P.; Hariri, S. [Ecole des Mines de Douai, 59 (France); Afzali, M.; Jaffal, H. [Centre Technique des Industries Mecaniques, 60 - Senlis (France)

    2008-11-15

    The aim of this work is to determine the evolution of the degree of noxiousness of a defect in a pressure equipment during its propagation. The estimation of the degree of noxiousness involves the calculation of stress intensity factors at each advance of the crack front. The cracks considered are semi-elliptic. The geometries and loads can be complex in order to cover the main industrial cases. Numerical modelling by finite element method is based on the creation of a crack-block, representing the optimized mesh near the discontinuity. The Paris law allows to describe the fatigue behaviour under cyclic load. A specific program (Python), having the advantages of the calculation codes Castem and Abaqus, allows to compute the propagation approach and makes easier the estimation of the residual lifetime of a structure under cracked pressure. (O.M.)

  9. A numerical simulation method of arc welding; Une methode de simulation numerique du soudage a l arc

    Energy Technology Data Exchange (ETDEWEB)

    Chau, T.T. [AREVA TA (Technicatome), Centre Jean-Louis Andrieu, BP34000, 13791 Aix-en-Provence Commission Simulation Numerique du Soudage (AFM / SNS), Paris La Defense (France)

    2006-07-01

    Nowadays, in metal industries, are more and more used weak thicknesses steel sheets to reduce the mass and optimize the resistance of the structures to make with the electric arc welding which remains always the most used and most economical technique. Deformations and residual stresses of most or less important levels are introduced too in the assembling thus welded. The methodology presented here can help the designer-manufacturer engineer to estimate the levels of these effects and to optimize the design and manufacture parameters for reaching the wanted performances in his plans with few computer time on 3D numerical models of great sizes. (O.M.)

  10. For an offshore construction: a digital control orbital system; Pour une construction offshore, un systeme orbital a commande numerique

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2006-01-15

    To carry out in offshore conditions, a pipeline in South-East Asia, the Korean Hyundai has retained an orbital welding system running with several pairs of torches perfectly synchronized with their digital control. (O.M.)

  11. Antibiotic-Associated Diarrhea

    Science.gov (United States)

    Antibiotic-associated diarrhea Overview By Mayo Clinic Staff Antibiotic-associated diarrhea refers to passing loose, watery stools ... after taking medications used to treat bacterial infections (antibiotics). Most often, antibiotic-associated diarrhea is mild and ...

  12. A characterization of associativity

    Science.gov (United States)

    Charlesworth, Arthur

    1990-01-01

    A necessary and sufficient condition for associativity of a function is given, in terms of a particular relation being a function. The concept of an associative function is generalized to the concept of a function being asssociative relative to a sequence and a characterization of such relative associativity is also given. These two characteristics are applied to the problem of proving the associativity, or relative associativity, of a function.

  13. National Vulvodynia Association

    Science.gov (United States)

    ... 20 years, the National Vulvodynia Association (NVA) , a nonprofit organization, has been dedicated to improving the health and ... of Use The National Vulvodynia Association is a nonprofit organization that strives to improve women's lives through education, ...

  14. Associated Health Allocation

    Data.gov (United States)

    Department of Veterans Affairs — The Associated Health Allocation Database is used to determine the allocation of positions and funds for VA Associated Health programs offered by Veterans Affairs...

  15. American Nephrology Nurses' Association

    Science.gov (United States)

    ... Help Join/Renew Jobs Contact Corporate Shop American Nephrology Nurses' Association About ANNA Association About ANNA Strategic ... Activities CExpress Events National Events Chapter / Local Events Nephrology Nurses Week ANNA Education Modules CKD Modules Education ...

  16. Dysglycemia associated with quinolones.

    Science.gov (United States)

    El Ghandour, Sarah; Azar, Sami T

    2015-06-01

    Antimicrobial therapy is well known to be associated with fluctuations of blood glucose levels. This review aims at exploring the association between glycemic fluctuations and antibiotics mainly focusing on quinolones. Quinolones are associated with hypoglycemia and hyperglycemia. Several mechanism are proposed to explain this causality.

  17. Intended Brand Associations

    DEFF Research Database (Denmark)

    Koll, Oliver; von Wallpach, Sylvia

    2014-01-01

    of actual consumer brand associations and management-intended brand associations (brand association match). The article presents results from two large-scale studies (3353 and 1201 respondents) involving one consumer goods and one service brand with multiple operationalizations of consumer response...... (attitudinal and behavioral). The results show that consumers with high brand association match show more positive brand response. However, after accounting for the valence of associations match does not add explanatory power. This outcome challenges a key foundation of brand management. The discussion......Brand managers exhibit considerable effort to define intended brand associations to anchor in consumers' minds. They follow a credo deeply rooted in branding literature: intended brand associations drive consumer response and brand equity. This article investigates the benefits of a strong overlap...

  18. Italian library associations

    Directory of Open Access Journals (Sweden)

    Ksenija Petaros-Kmetec

    2004-01-01

    Full Text Available In Italy, five library associations of national significance function at present. There are special associations of ecclesiastic libraries, prison libraries, architecture libraries and libraries with artistic material. The role of the general national association, covering all types of libraries including documentation centres, is played by the Italian Library Association. It strive for the development of a contemporary Italian library system comparable to international standards, monitors library legislation, promotes education for librarians and keeps the librarians and the broader public informed about the importance of libraries and librarianship for society. The activity and efforts of the association are reflected through their website offering much information and links to similar sites. ILA presents and realises its activities for both, the librarians and the public users. A great deal of actions promoting libraries and the Library Association might be interesting for Slovenia and perhaps transferred to our environment.

  19. Associativity as Commutativity

    OpenAIRE

    Dosen, K.; Petric, Z.

    2005-01-01

    It is shown that coherence conditions for monoidal categories concerning associativity are analogous to coherence conditions for symmetric or braided strictly monoidal categories, where associativity arrows are identities. Mac Lane's pentagonal coherence condition for associativity is decomposed into conditions concerning commutativity, among which we have a condition analogous to naturality and a degenerate case of Mac Lane's hexagonal condition for commutativity. This decomposition is analo...

  20. Class Association Rule Pada Metode Associative Classification

    Directory of Open Access Journals (Sweden)

    Eka Karyawati

    2011-11-01

    Full Text Available Frequent patterns (itemsets discovery is an important problem in associative classification rule mining.  Differents approaches have been proposed such as the Apriori-like, Frequent Pattern (FP-growth, and Transaction Data Location (Tid-list Intersection algorithm. This paper focuses on surveying and comparing the state of the art associative classification techniques with regards to the rule generation phase of associative classification algorithms.  This phase includes frequent itemsets discovery and rules mining/extracting methods to generate the set of class association rules (CARs.  There are some techniques proposed to improve the rule generation method.  A technique by utilizing the concepts of discriminative power of itemsets can reduce the size of frequent itemset.  It can prune the useless frequent itemsets. The closed frequent itemset concept can be utilized to compress the rules to be compact rules.  This technique may reduce the size of generated rules.  Other technique is in determining the support threshold value of the itemset. Specifying not single but multiple support threshold values with regard to the class label frequencies can give more appropriate support threshold value.  This technique may generate more accurate rules. Alternative technique to generate rule is utilizing the vertical layout to represent dataset.  This method is very effective because it only needs one scan over dataset, compare with other techniques that need multiple scan over dataset.   However, one problem with these approaches is that the initial set of tid-lists may be too large to fit into main memory. It requires more sophisticated techniques to compress the tid-lists.

  1. National Aphasia Association

    Science.gov (United States)

    ... challenge. […] National Aphasia Association Response to Statements by Trump Campaign Spokesperson In response to a recent statement by Trump campaign spokesperson, Katrina Pierson, and the article which ...

  2. Linguistic Valued Association Rules

    Institute of Scientific and Technical Information of China (English)

    LU Jian-jiang; QIAN Zuo-ping

    2002-01-01

    Association rules discovering and prediction with data mining method are two topics in the field of information processing. In this paper, the records in database are divided into many linguistic values expressed with normal fuzzy numbers by fuzzy c-means algorithm, and a series of linguistic valued association rules are generated. Then the records in database are mapped onto the linguistic values according to largest subject principle, and the support and confidence definitions of linguistic valued association rules are also provided. The discovering and prediction methods of the linguistic valued association rules are discussed through a weather example last.

  3. PADB : Published Association Database

    Directory of Open Access Journals (Sweden)

    Lee Jin-Sung

    2007-09-01

    Full Text Available Abstract Background Although molecular pathway information and the International HapMap Project data can help biomedical researchers to investigate the aetiology of complex diseases more effectively, such information is missing or insufficient in current genetic association databases. In addition, only a few of the environmental risk factors are included as gene-environment interactions, and the risk measures of associations are not indexed in any association databases. Description We have developed a published association database (PADB; http://www.medclue.com/padb that includes both the genetic associations and the environmental risk factors available in PubMed database. Each genetic risk factor is linked to a molecular pathway database and the HapMap database through human gene symbols identified in the abstracts. And the risk measures such as odds ratios or hazard ratios are extracted automatically from the abstracts when available. Thus, users can review the association data sorted by the risk measures, and genetic associations can be grouped by human genes or molecular pathways. The search results can also be saved to tab-delimited text files for further sorting or analysis. Currently, PADB indexes more than 1,500,000 PubMed abstracts that include 3442 human genes, 461 molecular pathways and about 190,000 risk measures ranging from 0.00001 to 4878.9. Conclusion PADB is a unique online database of published associations that will serve as a novel and powerful resource for reviewing and interpreting huge association data of complex human diseases.

  4. Associative Analysis in Statistics

    Directory of Open Access Journals (Sweden)

    Mihaela Muntean

    2015-03-01

    Full Text Available In the last years, the interest in technologies such as in-memory analytics and associative search has increased. This paper explores how you can use in-memory analytics and an associative model in statistics. The word “associative” puts the emphasis on understanding how datasets relate to one another. The paper presents the main characteristics of “associative” data model. Also, the paper presents how to design an associative model for labor market indicators analysis. The source is the EU Labor Force Survey. Also, this paper presents how to make associative analysis.

  5. Scleroderma associated with ANCA-associated vasculitis.

    Science.gov (United States)

    Rho, Young Hee; Choi, Seong Jae; Lee, Young Ho; Ji, Jong Dae; Song, Gwan Gyu

    2006-03-01

    We have recently reported on two cases of scleroderma patients with ANCA-associated vasculitis for the first time in Korea. In order to explore the nature of this disease combination, we pooled together all the previously known cases and statistically analyzed them. Out of the 50 selected cases, survival analysis was done for comparison of the scleroderma disease period and the clinical factors associated with ANCA-associated vasculitis (AAV). Kaplan-Meier analysis revealed that patients having anti-topoisomerase antibody (anti-Scl-70) and, probably, PR-3 ANCA are at a higher risk for developing AAV than patients without both anti-topoisomerase antibody and anti-centromere antibody (ACA), and patients with MPO-ANCA. Multivariate Cox regression analysis revealed having anti-topoisomerase antibody as a risk factor for developing AAV [OR 3.1 (95% CI 1.11-8.55), P=0.031]. We suggest that having anti-topoisomerase antibodies may play a role among scleroderma patients in developing AAV.

  6. Prevalence and associated f

    Directory of Open Access Journals (Sweden)

    Wafaa Yousif Abdel Wahed

    2017-03-01

    Conclusion: A substantial proportion of medical students are suffering from depression, stress, and anxiety. Female sex, increasing age, overweight and obesity are significant associated factors. Further studies need to be carried to identify other associated factors related to academic medical education.

  7. Migraine Associated Vertigo

    OpenAIRE

    Cha, Yoon-Hee; Baloh, Robert W.

    2007-01-01

    The interrelations of migraine and vertigo are complex, eluding a simple localization either centrally or peripherally. Spontaneous episodic vertigo, benign paroxysmal positional vertigo, and Meniere's disease all occur more frequently in patients with migraine than in those without. Family studies support a hereditary predisposition to migraine associated vertigo. In this review, we discuss definitions, epidemiology, associated syndromes, neurootological abnormalities, genetics and treatment...

  8. Graphs: Associated Markov Chains

    OpenAIRE

    2012-01-01

    In this research paper, weighted / unweighted, directed / undirected graphs are associated with interesting Discrete Time Markov Chains (DTMCs) as well as Continuous Time Markov Chains (CTMCs). The equilibrium / transient behaviour of such Markov chains is studied. Also entropy dynamics (Shannon entropy) of certain structured Markov chains is investigated. Finally certain structured graphs and the associated Markov chains are studied.

  9. Network Consistent Data Association.

    Science.gov (United States)

    Chakraborty, Anirban; Das, Abir; Roy-Chowdhury, Amit K

    2016-09-01

    Existing data association techniques mostly focus on matching pairs of data-point sets and then repeating this process along space-time to achieve long term correspondences. However, in many problems such as person re-identification, a set of data-points may be observed at multiple spatio-temporal locations and/or by multiple agents in a network and simply combining the local pairwise association results between sets of data-points often leads to inconsistencies over the global space-time horizons. In this paper, we propose a Novel Network Consistent Data Association (NCDA) framework formulated as an optimization problem that not only maintains consistency in association results across the network, but also improves the pairwise data association accuracies. The proposed NCDA can be solved as a binary integer program leading to a globally optimal solution and is capable of handling the challenging data-association scenario where the number of data-points varies across different sets of instances in the network. We also present an online implementation of NCDA method that can dynamically associate new observations to already observed data-points in an iterative fashion, while maintaining network consistency. We have tested both the batch and the online NCDA in two application areas-person re-identification and spatio-temporal cell tracking and observed consistent and highly accurate data association results in all the cases.

  10. Civic Engagement and Associationalism

    DEFF Research Database (Denmark)

    Alexander, Damon Timothy; Barraket, Jo; Lewis, Jenny;

    2012-01-01

    that individuals are involved with (associational scope). Does it matter in terms of civic engagement, for example, whether one is a member of a quilting-circle or trade union? Does it matter whether association ‘membership’ is simply an annual payment or a major commitment of time and energy? In this article, we...... use a large survey to explore these questions empirically by focusing on the membership patterns and civic engagement practices of 4,001 citizens drawn from eight suburbs across Greater Melbourne, Australia. Our findings indicate that, while associational intensity is positively related to civic...... engagement, associational scope (the number of group memberships per person), is a more influential determinant of the level of civic and political participation. The results also suggest that while all forms of associationalism are important in terms of fostering greater levels of civic activity, not all...

  11. Staff Association Cocktail

    CERN Multimedia

    Staff Association

    2017-01-01

    The Staff Association has been organising for many years a cocktail with delegates of the Member States participating in Finance Committees of March and September. This cocktail is held at the end of the day, after the Finance Committee meeting. This direct and regular communication helps establish an ongoing contact between the Staff Association and CERN Member States and, more recently, the Associate Member States. Ambassadors of the CERN Staff Association, who are Members of the Personnel, have the opportunity to meet their national delegation in an informal and friendly atmosphere. These exchanges, facilitated by the use of the national language, allow the personnel via the Staff Association to express its ideas and positions on current affairs and fundamental issues, and also to hear about those of the delegations in return.

  12. Italian Word Association Norms.

    Science.gov (United States)

    1966-07-01

    Ricerche Istituto Nazionale I Psicologia , Roma Italy. A different, but not unrelated, approach is to use word association norms to study other types of... Psicologia , 1961 , 55, 1,13-155. Chiari, S. 11 comportamento associative nell’eta ovolutiva, Rivista di Psicologia , 1 96 1b , 55, 175-189. Cofer, C.N...and Russell, VI.A. Systematic changes in word association norms: 1910-1952. Journal of Abnormal and Social Psychology, 19C0, 60, 293-303. lilb Kurez, I

  13. Linear associative algebras

    CERN Document Server

    Abian, Alexander

    1973-01-01

    Linear Associative Algebras focuses on finite dimensional linear associative algebras and the Wedderburn structure theorems.The publication first elaborates on semigroups and groups, rings and fields, direct sum and tensor product of rings, and polynomial and matrix rings. The text then ponders on vector spaces, including finite dimensional vector spaces and matrix representation of vectors. The book takes a look at linear associative algebras, as well as the idempotent and nilpotent elements of an algebra, ideals of an algebra, total matrix algebras and the canonical forms of matrices, matrix

  14. Celiac Support Association

    Science.gov (United States)

    ... America and support CSA. Click here to start shopping! Celiac SUPPORT ASSOCIATION ® GLUTEN-FREE RESOURCE DIRECTORY These ... visit www.schwans.com and register for an online account. Orders must be placed online to be ...

  15. Healthcare Associated Infections - State

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Healthcare-Associated Infections (HAI) measures - state data. These measures are developed by Centers for Disease Control and Prevention (CDC) and collected...

  16. Quantum Associative Memory

    CERN Document Server

    Ventura, D; Ventura, Dan; Martinez, Tony

    1998-01-01

    This paper combines quantum computation with classical neural network theory to produce a quantum computational learning algorithm. Quantum computation uses microscopic quantum level effects to perform computational tasks and has produced results that in some cases are exponentially faster than their classical counterparts. The unique characteristics of quantum theory may also be used to create a quantum associative memory with a capacity exponential in the number of neurons. This paper combines two quantum computational algorithms to produce such a quantum associative memory. The result is an exponential increase in the capacity of the memory when compared to traditional associative memories such as the Hopfield network. The paper covers necessary high-level quantum mechanical and quantum computational ideas and introduces a quantum associative memory. Theoretical analysis proves the utility of the memory, and it is noted that a small version should be physically realizable in the near future.

  17. National Stroke Association

    Science.gov (United States)

    ... Virginia Washington West Virginia Wisconsin Wyoming Go National Stroke Association Our mission is to reduce the incidence ... and support for all impacted by stroke. Understanding stroke and the recovery journey can be overwhelming, but ...

  18. American Pediatric Surgical Association

    Science.gov (United States)

    American Pediatric Surgical Association Search for: Login Resources + For Members For Professionals For Training Program Directors For Media For ... Surgical Outcomes Surveys & Results Publications Continuing Education + ExPERT Pediatric Surgery NaT Annual Meeting CME MOC Requirements Residents / ...

  19. American Health Care Association

    Science.gov (United States)

    ... Care Association Responds to Ruling on Injunction Delaying CMS Implementation of Arbitration Rule AHCA/NCAL Elects New ... Information Technology Integrity Medicaid Medicare Patient Privacy and Security Survey and Regulatory Therapy Services Workforce Events Calendar ...

  20. American Behcet's Disease Association

    Science.gov (United States)

    ... Behcet's Awareness Day Behcet's Disease Awareness Share your story and educate others about Behcet's: www.rareconnect.org/en/community/behcet-s-syndrome Upcoming Events American Behcet's Disease Association PO BOX 80576 Rochester, MI ...

  1. American Music Therapy Association

    Science.gov (United States)

    American Music Therapy Association Home Contact News Help/FAQ Members Only Login Quick Links Facts About Music Therapy Qualifications ... with AMTA Sponsor AMTA Events Social Networking Support Music Therapy When you shop at AmazonSmile, Amazon will ...

  2. Children's Craniofacial Association

    Science.gov (United States)

    ... Hemifacial Moebius syndrome Pfeiffer syndrome Pierre Robin Sequence Treacher Collins syndrome Other syndromes Wonder News & Events Help CCA ... Pierre Robin Sequence • Pfeiffer syndrome • Saethre-Chotzen syndrome • Treacher Collins syndrome Children's Craniofacial Association is a national, 501( ...

  3. Government, Marketplace, and Association.

    Science.gov (United States)

    Berry, John

    1988-01-01

    Summarizes events at the 1988 Canadian Library Association (CLA) annual conference, which addressed such issues as access to information, CLA finances, and the information marketplace. A list of CLA officers and awards is included. (MES)

  4. American Association of Orthodontists

    Science.gov (United States)

    ... step for patients wishing to resolve issues of crowding, misalignment and the burden of feeling self-conscious ... The American Association of Orthodontists does not provide funding for orthodontic treatment. There are several programs that ...

  5. American Sleep Apnea Association

    Science.gov (United States)

    American Sleep Apnea Association Learn About the CPAP Assistance Program About ASAA News about ASAA Who we are Leadership Team Supporting the ASAA Financials Learn Healthy sleep Sleep apnea Other sleep disorders Personal stories Treat Test Yourself ...

  6. Generalized Multidimensional Association Rules

    Institute of Scientific and Technical Information of China (English)

    周傲英; 周水庚; 金文; 田增平

    2000-01-01

    The problem of association rule mining has gained considerable prominence in the data mining community for its use as an important tool of knowl-edge discovery from large-scale databases. And there has been a spurt of research activities around this problem. Traditional association rule mining is limited to intra-transaction. Only recently the concept of N-dimensional inter-transaction as-sociation rule (NDITAR) was proposed by H.J. Lu. This paper modifies and extends Lu's definition of NDITAR based on the analysis of its limitations, and the general-ized multidimensional association rule (GMDAR) is subsequently introduced, which is more general, flexible and reasonable than NDITAR.

  7. National Military Family Association

    Science.gov (United States)

    ... 931.6632 info@MilitaryFamily.org © 2016 - National Military Family Association Twitter Facebook Pinterest Instagram Charity Navigator Four Star Charity GuideStar Exchange Better Business Bureau Charity Watch Independent Charity of America nonprofit ...

  8. Healthcare Associated Infections - Hospital

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Healthcare-Associated Infection (HAI) measures - provider data. These measures are developed by Centers for Disease Control and Prevention (CDC) and...

  9. Healthcare Associated Infections - National

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Healthcare-Associated Infections (HAI) measures - national data. These measures are developed by Centers for Disease Control and Prevention (CDC) and...

  10. American Sleep Association

    Science.gov (United States)

    ... Sleep Disorders Book Join ASA Press Room American Sleep Association Improving public health by increasing awareness about ... Members Username or Email Password Remember Me Register Sleep Blog Changing Bad Sleep Habits Asthma and Sleep ...

  11. Captopril-associated agranulocytosis

    African Journals Online (AJOL)

    1991-04-06

    Apr 6, 1991 ... Three cases of captopril-associated neutropenia are des- cribed, which illustrate the clinical presentation, variable pre- disposing factors .... tension after renal transplantation. Laruet 1980; I: ... Fatal bone marrow suppressIOn.

  12. Lewy Body Dementia Association

    Science.gov (United States)

    ... promoting scientific advances. Featured LBD Stories & Tributes Dad's Dementia Journey It's been years since my father passed ... I received an email from the Lewy Body Dementia Association about a benefit... Read Story The Lewy ...

  13. Staff Association Information Meetings

    CERN Multimedia

    2011-01-01

    Staff Association Information Meetings: - Thursday 29 September at 2 p.m., Meyrin, Kjell Johnsen Auditorium, 30-7-017 (in French) - Friday 30 September at 10 a.m., Prévessin, BE Auditorium, 864-1-D02 (in French) - Monday 3 October at 2 p.m., Meyrin, IT Auditorium, 31-3-004 (in French) - Tuesday 4 October at 2 p.m., Meyrin, Filtration Plant, 222-R-001 (in English)   Staff Association

  14. Thyroid associated orbitopathy

    Directory of Open Access Journals (Sweden)

    Rajat Maheshwari

    2012-01-01

    Full Text Available Thyroid associated orbitopathy, also known as Graves′ orbitopathy, is typically a self-limiting autoimmune process associated with dysthyroid states. The clinical presentation may vary from very mild disease to severe irreversible sight-threatening complications. Despite ongoing basic science and clinical research, the pathogenesis and highly effective therapeutic strategies remain elusive. The present article reviews the pathophysiology, clinical presentation, and management of this common, yet poorly understood disease, which remains a challenge to the ophthalmologist.

  15. Recurrent correlation associative memories.

    Science.gov (United States)

    Chiueh, T D; Goodman, R M

    1991-01-01

    A model for a class of high-capacity associative memories is presented. Since they are based on two-layer recurrent neural networks and their operations depend on the correlation measure, these associative memories are called recurrent correlation associative memories (RCAMs). The RCAMs are shown to be asymptotically stable in both synchronous and asynchronous (sequential) update modes as long as their weighting functions are continuous and monotone nondecreasing. In particular, a high-capacity RCAM named the exponential correlation associative memory (ECAM) is proposed. The asymptotic storage capacity of the ECAM scales exponentially with the length of memory patterns, and it meets the ultimate upper bound for the capacity of associative memories. The asymptotic storage capacity of the ECAM with limited dynamic range in its exponentiation nodes is found to be proportional to that dynamic range. Design and fabrication of a 3-mm CMOS ECAM chip is reported. The prototype chip can store 32 24-bit memory patterns, and its speed is higher than one associative recall operation every 3 mus. An application of the ECAM chip to vector quantization is also described.

  16. Feasibility study of a new platform based on the Case-Based Reasoning principles to efficiently search and store voxel phantoms; Etude de faisabilite d'une plate-forme originale basee sur le raisonnement a partir de cas pour la recherche et le stockage de fantomes voxelises

    Energy Technology Data Exchange (ETDEWEB)

    Henriet, J.; Bopp, M.; Makovicka, L. [Universite de Franche-Comte, IRMA/ENISYS/FEMTO-ST, UMR 6174 CNRS, 25 - Montbeliard (France); Farah, J.; Broggio, D. [IRSN, LEDI/SDI/DPRH, 92 - Fontenay-aux-Roses (France); Chebel-Morello, B. [Universite de Franche-Comte, COSMI/AS2M/FEMTO-ST, UMR 6174 CNRS, 25 - Besancon (France)

    2010-01-15

    In case of accidental exposure to radiation, it is necessary to establish as soon as possible a dosimetry report for each victim. In most cases, this report is based on medical images of the victim, enabling the construction of a personalized realistic numerical model, also called a voxel phantom. Unfortunately it is not always possible to perform the medical imaging of the victim since the technology may be unavailable or to avoid additional exposure to radiation. In such cases, the commonly used method is to represent the victim with a numerical model like the 'Reference Man', a voxelized phantom representative of the average male individual. The treatment accuracy depends on the diagnosis precision and, consequently, on the similarity of the phantom and/to the victim. A precise dosimetry evaluation requires a personalized and realistic phantom whose bio metric characteristics match the victim; such model is often unavailable. The Case-Based Reasoning (C.B.R.) is a problem solving method for the conception of intelligent systems. It imitates the analysis, understanding and reconstruction of the human intelligence. The ReEPh project (Research of Equivalent Phantom) proposes to use the case-based reasoning (C.B.R.) principles to retrieve from a set of phantoms, the most adapted one to the irradiated victim. For this study, the ReEPh platform retrieves, stores and compares existing phantoms to a victim. A graphic interface enables the user to compare victim characteristics to the ones of the most similar phantoms available in the database. This defines a similarity index presenting the equivalence between the victim and the suggested phantom. Moreover, a confidence index is also assessed to define the uncertainty implied by the reasoning from a case (RaPC) choice procedure. (authors)

  17. Bipolar spectral associative memories.

    Science.gov (United States)

    Spencer, R G

    2001-01-01

    Nonlinear spectral associative memories are proposed as quantized frequency domain formulations of nonlinear, recurrent associative memories in which volatile network attractors are instantiated by attractor waves. In contrast to conventional associative memories, attractors encoded in the frequency domain by convolution may be viewed as volatile online inputs, rather than nonvolatile, off-line parameters. Spectral memories hold several advantages over conventional associative memories, including decoder/attractor separability and linear scalability, which make them especially well suited for digital communications. Bit patterns may be transmitted over a noisy channel in a spectral attractor and recovered at the receiver by recurrent, spectral decoding. Massive nonlocal connectivity is realized virtually, maintaining high symbol-to-bit ratios while scaling linearly with pattern dimension. For n-bit patterns, autoassociative memories achieve the highest noise immunity, whereas heteroassociative memories offer the added flexibility of achieving various code rates, or degrees of extrinsic redundancy. Due to linear scalability, high noise immunity and use of conventional building blocks, spectral associative memories hold much promise for achieving robust communication systems. Simulations are provided showing bit error rates for various degrees of decoding time, computational oversampling, and signal-to-noise ratio.

  18. Prediction inverse d'un front de solidification dans un four de transformation a haute temperature

    Science.gov (United States)

    Marois, Marc-Andre

    Ce projet de recherche porte sur une methode numerique permettant de predire l'evolution du profil 2D de la couche solide qui recouvre l'interieur des parois de plusieurs fours de transformation a haute temperature. Un modele mathematique base sur la formulation faible de l'energie est d'abord developpe et valide. Une methode de transfert thermique inverse reposant sur ce modele est ensuite developpee afin d'obtenir une mesure rapide et continue de l'evolution du profil de cette couche solide. Vu la grande inertie thermique du systeme a l'etude, differentes strategies sont proposees afin de faciliter la mise en uvre de cette methode numerique. Finalement, cette approche inverse est confrontee aux resultats experimentaux obtenus a l'aide d'un reacteur metallurgique. Une etude preliminaire montre que les fours de transformation presentent une tres grande inertie thermique qui limite grandement l'utilisation des methodes inverses. En effet, la sensibilite de cette methode numerique repose essentiellement sur le delai temporel observe entre la variation du profil du banc et la fluctuation de la temperature a la surface externe de la paroi du four. Les resultats obtenus demontrent qu'une partie de ce delai est proportionnel a la chaleur latente de fusion lorsque le materiau a changement de phase est constitue d'un melange non eutectique. Afin de limiter l'impact de ce delai temporel, deux astuces numeriques sont proposees : reutiliser plus d'une fois les mesures de temperature et modifier le probleme thermique dans les regions pateuse et liquide. D'une part, le concept de chevauchement propose permet de reduire le temps d'acquisition des donnees entre chacune des predictions. D'autre part, l'approche virtuelle developpee permet de reduire l'inertie thermique du systeme et, par le fait meme, le delai temporel associe a la diffusion de la chaleur. Ces deux strategies ont permis de predire efficacement l'evolution 1D de l'epaisseur de la couche de gelee qui se solidifie a

  19. Immunological memory is associative

    Energy Technology Data Exchange (ETDEWEB)

    Smith, D.J.; Forrest, S. [New Mexico Univ., Albuquerque, NM (United States). Dept. of Computer Science; Perelson, A.S. [Los Alamos National Lab., NM (United States)

    1996-12-31

    The purpose of this paper is to show that immunological memory is an associative and robust memory that belongs to the class of sparse distributed memories. This class of memories derives its associative and robust nature by sparsely sampling the input space and distributing the data among many independent agents. Other members of this class include a model of the cerebellar cortex and Sparse Distributed Memory (SDM). First we present a simplified account of the immune response and immunological memory. Next we present SDM, and then we show the correlations between immunological memory and SDM. Finally, we show how associative recall in the immune response can be both beneficial and detrimental to the fitness of an individual.

  20. China International Cultural Association

    Institute of Scientific and Technical Information of China (English)

    1992-01-01

    China International Cultural Association (hereafterreferred to as the association)was founded on July3,1986.It is a nationwide social group engaged inexternal cultural exchange between peoples.Its purpose isto develop cultural exchange and cooperation with allcountries in the world,promote culturJ ullderkings.im-prove understanding and friendship between the Chinesepeople and peoples of the world,promote social progress,and defend world peace.On the basis of equality andmutual benefit we hope to conduct exchange and coopera-tion with all countries through visits,the exchange of booksand reference materials,the holding of theatrical perform-ances and exhibitions,and the study of literature and art.The president of the association is Zu Muzhi; vice-presidents,Yu Wen,Chen Xinren,Zhou Weizhi,YaoZhongming,Wang Lanxi,L(?) Zhixian,Zeng Jianhui,LiuDeyou and Luo Jun; secretary,Wu Chunde.

  1. Maximum Likelihood Associative Memories

    OpenAIRE

    Gripon, Vincent; Rabbat, Michael

    2013-01-01

    Associative memories are structures that store data in such a way that it can later be retrieved given only a part of its content -- a sort-of error/erasure-resilience property. They are used in applications ranging from caches and memory management in CPUs to database engines. In this work we study associative memories built on the maximum likelihood principle. We derive minimum residual error rates when the data stored comes from a uniform binary source. Second, we determine the minimum amo...

  2. Acromegaly associated with gangliocytoma.

    LENUS (Irish Health Repository)

    Crowley, R K

    2009-09-30

    BACKGROUND: Acromegaly secondary to growth hormone-releasing hormone (GHRH) excess is rare. AIMS\\/CASE DESCRIPTION: We report two patients with acromegaly who were diagnosed with sellar gangliocytomas that were immunopositive for GHRH. Tumour tissue persisted after debulking surgery and in the second case this was associated with persistent growth hormone hypersecretion, successfully suppressed by a somatostatin analogue. CONCLUSIONS: The development of functional pituitary adenomas in association with sellar gangliocytomas is poorly understood. We present a brief discussion of the possible aetiology of these unusual pituitary tumours.

  3. AIDS and associated malignancies

    Institute of Scientific and Technical Information of China (English)

    Charles WOOD; William HARRINGTON Jr

    2005-01-01

    AIDS associated malignancies (ARL) is a major complication associated with AIDS patients upon immunosuppression.Chronically immunocompromised patients have a markedly increased risk of developing lymphoproliferative disease. In the era of potent antiretrovirals therapy (ARV), the malignant complications due to HIV- 1 infection have decreased in developed nations where ARV is administered, but still poses a major problem in developing countries where HIV- 1incidence is high and ARV is still not yet widely available. Even in ARV treated individuals there is a concern that the prolonged survival of many HIV- 1 carriers is likely to eventually result in an increased number of malignancies diagnosed.Malignancies that were found to have high incidence in HIV-infected individuals are Kaposi's sarcoma (KS), Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL). The incidence of NHL has increased nearly 200 fold in HIV-positive patients, and accounts for a greater percentage of AIDS defining illness in the US and Europe since the advent of HAART therapy. These AIDS related lymphomas are distinct from their counterparts seen in HIV- 1 seronegative patients.For example nearly half of all cases of ARL are associated with the presence of a gamma herpesvirus, Epstein Barr virus (EBV) or human herpesvirus-8 (HHV-8)/Kaposi's sarcoma associated herpesvirus (KSHV). The pathogenesis of ARLs is complex. B-cell proliferation driven by chronic antigenemia resulting in the induction of polyclonal and ultimately monoclonal lymphoproliferation may occur in the setting of severe immunosuppression.

  4. Fluoroquinolone-associated tendinopathy.

    Science.gov (United States)

    Tsai, Wen-Chung; Yang, Yun-Ming

    2011-01-01

    The fluoroquinolones (FQs) are used to treat a wide range of infections because of their excellent gastrointestinal absorption, superior tissue penetration and broad-spectrum activity. Recently, FQ-associated tendinopathy and tendon rupture have been reported, especially in the elderly and patients with diabetes and renal failure. However, these adverse effects do not appear to be widely known among physicians. Because of the frequent use of FQs in clinical practice, physicians should be aware of their potential for severe disability from tendon rupture. Achilles tendinopathy or rupture is among the most serious side effects associated with FQ use, with reports markedly increasing, especially with the use of ciprofloxacin. The histopathologic findings include degenerative lesions, fissures, interstitial edema without cellular infiltration, necrosis and neovascularization. There are possible molecular mechanisms accounting for FQ-associated tendinopathy. First, ciprofloxacin mediates inhibition of cell proliferation and G2/M cell cycle arrest in tendon cells by down-regulation of cyclin B and cyclin-dependent kinase 1. Second, ciprofloxacin inhibits the spead and migration of tenocytes by down-regulation of focal adhesion kinase phosphorylation. Third, ciprofloxacin enhances the enzymatic activity of matrix metalloproteinase-2 with degradation of type I collagen. Management of FQ-associated tendinopathy includes immediate discontinuation of FQs, rest, non-steroidal anti-inflammatory drugs, physical modalities and eccentric strengthening exercise. Tendon rupture may require surgical intervention.

  5. Hypertrophic Cardiomyopathy Association

    Science.gov (United States)

    ... be donated to Hypertrophic Cardiomyopathy Association. iGive.com - Online Shopping Joing iGive.com to earn money for the ... it works, check out the iGive website . AmazonSmile - Online Shopping Amazon donates 0.5% of the purchase price ...

  6. Osteosarcoma associated with hyperparathyroidism

    NARCIS (Netherlands)

    Jutte, PC; Rosso, R; de Paolis, M; Errani, C; Pasini, E; Campanacci, L; Bacci, G; Bertoni, F; Mercuri, M

    2004-01-01

    The fourth case in the literature is presented of a patient with the rare association of hyperparathyroidism and osteosarcoma. A 56-year-old woman presented with hyperparathyroidism and a lesion in the tibia. Initial diagnosis was brown tumor. Histology, however, revealed osteosarcoma, and the patie

  7. Osteosarcoma associated with hyperparathyroidism

    NARCIS (Netherlands)

    Jutte, PC; Rosso, R; de Paolis, M; Errani, C; Pasini, E; Campanacci, L; Bacci, G; Bertoni, F; Mercuri, M

    2004-01-01

    The fourth case in the literature is presented of a patient with the rare association of hyperparathyroidism and osteosarcoma. A 56-year-old woman presented with hyperparathyroidism and a lesion in the tibia. Initial diagnosis was brown tumor. Histology, however, revealed osteosarcoma, and the patie

  8. Osteosarcoma associated with hyperparathyroidism

    NARCIS (Netherlands)

    Jutte, PC; Rosso, R; de Paolis, M; Errani, C; Pasini, E; Campanacci, L; Bacci, G; Bertoni, F; Mercuri, M

    The fourth case in the literature is presented of a patient with the rare association of hyperparathyroidism and osteosarcoma. A 56-year-old woman presented with hyperparathyroidism and a lesion in the tibia. Initial diagnosis was brown tumor. Histology, however, revealed osteosarcoma, and the

  9. HIV Associated Sensory Neuropathy

    OpenAIRE

    G, Amruth; S, Praveen-kumar; B, Nataraju; BS, Nagaraja

    2014-01-01

    Background: In the era of highly active antiretroviral therapy, sensory neuropathies have increased in prevalence. We have documented the frequency and profile of the two most common forms of sensory neuropathies associated with Human Immunodeficiency Virus (HIV) infection and looked into clinicoelectrophysiological correlates to differentiate the two entities.

  10. Registered Nurse (Associate Degree).

    Science.gov (United States)

    Ohio State Univ., Columbus. Center on Education and Training for Employment.

    This document, which is designed for use in developing a tech prep competency profile for the occupation of registered nurse (with an associate degree), lists technical competencies and competency builders for 19 units pertinent to the health technologies cluster in general and 5 units specific to the occupation of registered nurse. The following…

  11. Interstitial Cystitis Association

    Science.gov (United States)

    ... Symptoms. Get the Facts! Struggling with bladder pain, urinary urgency/frequency? You may have IC. Get The Facts ... the bladder and pelvic region, often associated with urinary frequency (needing to go often) and urgency (feeling a strong need to go). IC can ...

  12. Optical Bidirectional Associative Memories

    Science.gov (United States)

    Kosko, Bart; Guest, Clark

    1987-06-01

    Four optical implementations of bidirectional associative memories (BAMs) are presented. BAMs are heteroassociative content addressable memories (CAMs). A BAM stores the m binary associations (A1, B1), ..., (Am, Bm) , where A is a point in the Boolean n-cube and B is a point in the Boolean p-cube. A is a neural network of n bivalent or continuous neurons ai; B is a network of p bivalent or continuous neurons bi. The fixed synaptic connections between the A and B networks are represented by some n-by-p real matrix M. Bidirectionality, forward and backward information flow, in neural nets produces two-way associative search for the nearest stored pair (Ai, Bi) to an input key. Every matrix is a bidirectionally stable hetero-associative CAM for boh bivalent and continuous networks. This generalizes the well-known unidirectional stability for autoassociative networks with square symmetric M. When the BAM neurons are activated, the network quickly evolves to a stable state of two-pattern reverberation, or pseudo-adaptive resonance. The stable reverberation corresponds to a system energy local minimum. Heteroassociative pairs (Ai, Bi) are encoded in a BAM M by summing bipolar correlation matrices, M = X1T Y1 + ... + XmT Ym , where Xi (Yi) is the bipolar version of Ai (Bi), with -1s replacing Os. the BAM storage capacity for reliable recall is roughly m reflection hologram, and a transmission hologram.

  13. Whiplash-Associated Disorders

    DEFF Research Database (Denmark)

    Ferrara, S. D.; Ananian, V.; Baccino, E.

    2016-01-01

    The manuscript presents the International Guidelines developed by the Working Group on Personal Injury and Damage under the patronage of the International Academy of Legal Medicine (IALM) regarding the Methods of Ascertainment of any suspected Whiplash-Associated Disorders (WAD). The document inc...

  14. Refugee by association

    Directory of Open Access Journals (Sweden)

    Blanche Tax

    2014-09-01

    Full Text Available Many Syrians, even when they have not been individually singled out, meet the refugee criteria on the grounds of being at risk of persecution because of a perceived association, in the broadest sense, with one of the parties to the conflict.

  15. Lenalidomide-Associated ITP

    Directory of Open Access Journals (Sweden)

    Christina I. Herold

    2011-01-01

    Full Text Available Lenalidomide is a potent immunomodulatory agent being used increasingly for treatment of hematologic malignancies including multiple myeloma and myelodysplasia. The common toxicities of lenalidomide, including dose-limiting myelosuppression, are well described. However, the immunomodulatory properties of lenalidomide may give rise to unexpected autoimmune complications. Herein, we describe a case of immune thrombocytopenic purpura (ITP associated with use of lenalidomide.

  16. MUTYH Associated Polyposis (MAP)

    DEFF Research Database (Denmark)

    Poulsen, Marie Louise Mølgaard; Bisgaard, M L

    2008-01-01

    MUTYH Associated Polyposis (MAP), a Polyposis predisposition caused by biallelic mutations in the Base Excision Repair (BER) gene MUTYH, confers a marked risk of colorectal cancer (CRC). The MAP phenotype is difficult to distinguish from other hereditary CRC syndromes. Especially from Familial...

  17. American Music Therapy Association

    Science.gov (United States)

    American Music Therapy Association Home Contact News Help/FAQ Members Only Login Quick Links Facts About Music Therapy Qualifications of ... with AMTA Sponsor AMTA Events Social Networking Support Music Therapy When you shop at AmazonSmile, Amazon will donate ...

  18. Fellows, Associates & Students Programmes

    CERN Document Server

    2005-01-01

    The present document reviews the CERN Fellows, Associates and Students Programmes emphasizing the developments since 2000, when the previous review was presented to the Scientific Policy Committee, Finance Committee and Council (CERN/2325), and makes proposals for the coming five years. In summary, it is proposed to â?¢ Simplify the payment scheme for the Paid Scientific Associates Programme, which will no longer depend on candidateâ??s home support and age; â?¢ Broaden the scope of the Fellowship Programme, in order to facilitate the recruitment of young graduates in computing and engineering. Age-related eligibility conditions and payment levels will be replaced with experience-based criteria; â?¢ Modify subsistence rates for the Doctoral and Technical Student Programme in order to harmonize CERNâ??s payment levels with those offered by other research establishments. This document is presented for discussion and recommendation by the Scientific Policy Committee and approval by the Council. Additiona...

  19. Fuzzy associative memories

    Science.gov (United States)

    Kosko, Bart

    1991-01-01

    Mappings between fuzzy cubes are discussed. This level of abstraction provides a surprising and fruitful alternative to the propositional and predicate-calculas reasoning techniques used in expert systems. It allows one to reason with sets instead of propositions. Discussed here are fuzzy and neural function estimators, neural vs. fuzzy representation of structured knowledge, fuzzy vector-matrix multiplication, and fuzzy associative memory (FAM) system architecture.

  20. Coupled Neural Associative Memories

    OpenAIRE

    Karbasi, Amin; Salavati, Amir Hesam; Shokrollahi, Amin

    2013-01-01

    We propose a novel architecture to design a neural associative memory that is capable of learning a large number of patterns and recalling them later in presence of noise. It is based on dividing the neurons into local clusters and parallel plains, very similar to the architecture of the visual cortex of macaque brain. The common features of our proposed architecture with those of spatially-coupled codes enable us to show that the performance of such networks in eliminating noise is drastical...

  1. Solsolitons associated with graphs

    CERN Document Server

    Lafuente, Ramiro A

    2010-01-01

    We show how to associate with each graph with a certain property (positivity) a family of simply connected solvable Lie groups endowed with left-invariant Riemannian metrics that are Ricci solitons (called solsolitons). We classify them up to isometry, obtaining families depending on many parameters of explicit examples of Ricci solitons. A classification of graphs with up to 3 coherent components according to positivity is also given.

  2. Lithium associated autoimmune thyroiditis.

    OpenAIRE

    Shimizu, M; Hirokawa, M.; T. Manabe; Shimozuma, K; Sonoo, H; Harada, T.

    1997-01-01

    A case of autoimmune thyroiditis after long term treatment with lithium is described in a 29 year old Japanese woman with manic depression. Positive serum antithyroglobulin and antimicrosomal antibodies, diffuse goitre, and microscopic chronic thyroiditis, as well as the clinical history of long term lithium treatment were suggestive of lithium associated autoimmune thyroiditis. Microscopically, there was a mild degree of interstitial fibrosis and a moderate degree of lymphocytic infiltration...

  3. The Growth-Inequality Association:

    DEFF Research Database (Denmark)

    Bjørnskov, Christian

    2008-01-01

    This note suggests that the association between income inequality and economic growth rates might arguably depend on the political ideology of incumbent governments. Estimates indicate that under leftwing governments, inequality is negatively associated with growth while the association is positive...

  4. [Risks associated with vaccinations].

    Science.gov (United States)

    Loupi, E; Baudard, S; Debois, H; Pignato, F

    1998-10-01

    Since Jenner and Pasteur, various vaccines have been developed and administered in immunization program conducted by WHO in order to diminish the circulation of pathogenic agents and eradicate some diseases. Risks associated with immunization are revealed by the collection and assessment of adverse events reported after the use of these drugs. They vary according to the type of vaccines. With high rates of immunization and a low incidence of infectious diseases, adverse events receive increasing attention. Frequent and mostly expected adverse events are reported in clinical trials. Unexpected rare adverse events are reported after marketing authorization by spontaneous reporting and post marketing surveillance studies. Post marketing surveillance should be adapted to vaccines (vaccino-vigilance) and should take into account the risk linked to the disease they may protect against. Adverse events are often temporally associated with vaccines, that does not mean they are causally related. Specific studies should be conducted to assess the causal relationship between vaccines and post immunization adverse events. In order to reduce the risk associated with immunization, a strict follow-up of recommendations, warnings and contraindications in addition to appropriate information being delivered to both vaccinees and physicians are required.

  5. Scoliosis Associated With Syringomyelia

    Directory of Open Access Journals (Sweden)

    Gh Fathi

    2007-01-01

    Full Text Available Introduction: The differential diagnosis of idiopathic and syringomyelia associated scoliosis is important because corrective surgery for scoliosis associated with syringomyelia prior to management of syringomyelia can be dangerous. There are important imaging indicators for diagnosis of syringomyelia associated with scoliosis. A few of these indicators have been assessed in our study. Methods: A retrospective descriptive study including 38 patients with both scoliosis and syringomyelia was performed at the Shafa Yahyaeian center. Standard scoliosis series radiographs and MRI of all patients were studied. The type of scoliosis, location and magnitude of deformity, kyphosis or lordosis in the sagittal plane, location and size of syrinx were assessed. Results: Thoracic kyphosis was present in 94.7% of patients. 37% of patients had scoliosis with convexity to left. Arnold –chiari malformation was present in 36% and cord tethering in 21% of patients. The locations of syrinx were as follows: 47.4%cervical, 44.6 thoracic, 2.7% lumbar and 5.3% were holocord. Conclusion: Kyphosis, abscence of lordosis in sagittal plane, progressive scoliosis and scoliosis with convexity to left are atypical findings and could be indicators of the presence of syringomyelia. If these indicators are present, a diagnosis of idiopathic scoliosis should be made with caution.

  6. VACTERL/VATER Association

    Directory of Open Access Journals (Sweden)

    Solomon Benjamin D

    2011-08-01

    Full Text Available Abstract VACTERL/VATER association is typically defined by the presence of at least three of the following congenital malformations: vertebral defects, anal atresia, cardiac defects, tracheo-esophageal fistula, renal anomalies, and limb abnormalities. In addition to these core component features, patients may also have other congenital anomalies. Although diagnostic criteria vary, the incidence is estimated at approximately 1 in 10,000 to 1 in 40,000 live-born infants. The condition is ascertained clinically by the presence of the above-mentioned malformations; importantly, there should be no clinical or laboratory-based evidence for the presence of one of the many similar conditions, as the differential diagnosis is relatively large. This differential diagnosis includes (but is not limited to Baller-Gerold syndrome, CHARGE syndrome, Currarino syndrome, deletion 22q11.2 syndrome, Fanconi anemia, Feingold syndrome, Fryns syndrome, MURCS association, oculo-auriculo-vertebral syndrome, Opitz G/BBB syndrome, Pallister-Hall syndrome, Townes-Brocks syndrome, and VACTERL with hydrocephalus. Though there are hints regarding causation, the aetiology has been identified only in a small fraction of patients to date, likely due to factors such as a high degree of clinical and causal heterogeneity, the largely sporadic nature of the disorder, and the presence of many similar conditions. New genetic research methods offer promise that the causes of VACTERL association will be better defined in the relatively near future. Antenatal diagnosis can be challenging, as certain component features can be difficult to ascertain prior to birth. The management of patients with VACTERL/VATER association typically centers around surgical correction of the specific congenital anomalies (typically anal atresia, certain types of cardiac malformations, and/or tracheo-esophageal fistula in the immediate postnatal period, followed by long-term medical management of sequelae of

  7. Herpes associated erythema multiforme

    Directory of Open Access Journals (Sweden)

    K A Kamala

    2011-01-01

    Full Text Available Erythema multiforme is an acute and a self-limiting mucocutaneous hypersensitivity reaction triggered by certain infections and medications. One of the most common predisposing factors for erythema multiforme is infection with herpes simplex virus. Herpes associated erythema multiforme (HAEM is an acute exudative dermatic and mucosal disease caused by the infecting herpes simplex virus. It has recurrence and idiorestriction, characterized by increasing of CD4+T leukomonocyte. This article reports a case of HAEM in a 9-year-old girl, with a review of relevant literature, and discusses the pathophysiology and treatment of erythema multiforme triggered by herpes simplex virus

  8. Osteosarcoma associated with hyperparathyroidism

    Energy Technology Data Exchange (ETDEWEB)

    Jutte, Paul C. [Istituti Orthopedici Rizzoli, Via Pupilli 1, 40136, Bologna (Italy); University Medical Center Groningen, PO Box 30.001, 9700 RB, Groningen (Netherlands); Rosso, Renato [Anatomia Patologica Universita di Pavia, via Forlanini 16, 27100, Pavia (Italy); Paolis, Massimiliano de; Errani, Costatino; Pasini, Elisabetta; Campanacci, Laura; Bacci, Gaetano; Bertoni, Franco; Mercuri, Mario [Istituti Orthopedici Rizzoli, Via Pupilli 1, 40136, Bologna (Italy)

    2004-08-01

    The fourth case in the literature is presented of a patient with the rare association of hyperparathyroidism and osteosarcoma. A 56-year-old woman presented with hyperparathyroidism and a lesion in the tibia. Initial diagnosis was brown tumor. Histology, however, revealed osteosarcoma, and the patient was treated accordingly. The experimental induction of osteosarcoma by parathormone in rodent studies makes this finding alarming, considering the increasing use of parathormone in the treatment of osteoporosis. The mechanism by which osteosarcoma is induced in humans cannot be explained based on current knowledge of mechanisms of action of parathyroid hormone. (orig.)

  9. Extended associative memories

    OpenAIRE

    J.H Sossa Azuela; R. Barrón Fernández

    2007-01-01

    The #945; #946; associative memories recently developed in Ref 10 have proven to be powerful tools for memorizing and recalling patterns when they appear distorted by noise. However they are only useful in the binary case. In this paper we show that it is possible to extend these memories now to the gray-level case. To get the desired extension, we take the original operators #945; and #946;, foundation of the #945; #946; memories, and propose a more general family of operators. We find t...

  10. Pentatomids associated with blackberry

    Directory of Open Access Journals (Sweden)

    Mauricio Paulo Batistella Pasini

    2014-06-01

    Full Text Available Information concerning the presence of stink bugs in blackberry (Rubus spp. in Brazil is sparse. This study aimed to identify the stink bug species associated with blackberry, to establish the daily dynamics and evaluate the fruits damage. The experiment was conducted in Santa Maria, Rio Grande do Sul State, Brazil, in blackberry orchard. Presence and evaluations of stink bugs were done weekly through visual and sweeping samplings at different day times. Five species of pentatomids were identified: Piezodorus guildinii, Nezara viridula, Euschistus heros, Dichelops furcatus and Edessa meditabunda. The bugs attack the drupelets producing a dark brown spot and wrinkled berries.

  11. Lithium-associated hyperthyroidism.

    Science.gov (United States)

    Siyam, Fadi F; Deshmukh, Sanaa; Garcia-Touza, Mariana

    2013-08-01

    Goiters and hypothyroidism are well-known patient complications of the use of lithium for treatment of bipolar disease. However, the occurrence of lithium-induced hyperthyroidism is a more rare event. Many times, the condition can be confused with a flare of mania. Monitoring through serial biochemical measurement of thyroid function is critical in patients taking lithium. Hyperthyroidism induced by lithium is a condition that generally can be controlled medically without the patient having to discontinue lithium therapy, although in some circumstances, discontinuation of lithium therapy may be indicated. We report on a patient case of lithium-associated hyperthyroidism that resolved after discontinuation of the medication.

  12. Vaccine Associated Myocarditis

    Directory of Open Access Journals (Sweden)

    Johnson Francis

    2017-04-01

    Full Text Available Most of the cases of vaccine associated myocarditis have been following small pox vaccination. Reports have also been there after streptococcal pneumonia vaccine and influenza vaccine. In some cases, autoimmune/inflammatory syndrome induced by adjuvants (ASIA used in the vaccine have been implicated. Exclusion of other causes is very important in the diagnostic process, especially that of acute coronary syndrome. Management is similar to that of other etiologies of myocarditis. These rare instances of myocarditis should not preclude one from taking necessary immunization for vaccine preventable diseases.

  13. Dermatosis associated with menopause

    Directory of Open Access Journals (Sweden)

    Pragya A Nair

    2014-01-01

    Full Text Available Menopause is defined as permanent irreversible cessation of menses brought by decline in ovarian follicular activity. Hormonal alteration results in various physical, psychological, and sexual changes in menopausal women. Associated dermatological problems can be classified as physiological changes, age-related changes, changes due to estrogen deficiency and due to hormone replacement therapy. Dermatosis seen due to estrogen deficiency includes Atrophic Vulvovaginitis, Vulvar Lichen Sclerosus, Dyaesthetic Vulvodynia, Hirsutism, Alopecia, Menopausal Flushing, Keratoderma Climactericum, Vulvovaginal Candidiasis. Dermatologists and gynecologists need to be familiar with the problems of menopausal women, as with increase in life expectancy, women passing through this phase is rising.

  14. Towards Predictive Association Theories

    DEFF Research Database (Denmark)

    Kontogeorgis, Georgios; Tsivintzelis, Ioannis; Michelsen, Michael Locht

    2011-01-01

    Association equations of state like SAFT, CPA and NRHB have been previously applied to many complex mixtures. In this work we focus on two of these models, the CPA and the NRHB equations of state and the emphasis is on the analysis of their predictive capabilities for a wide range of applications...... and water–MEG–aliphatic hydrocarbons LLE using interaction parameters obtained from the binary data alone. Moreover, it is demonstrated that the NRHB equation of state is a versatile tool which can be employed equally well to mixtures with pharmaceuticals and solvents, including mixed solvents, as well...

  15. Morphological associative memories.

    Science.gov (United States)

    Ritter, G X; Sussner, P; Diza-de-Leon, J L

    1998-01-01

    The theory of artificial neural networks has been successfully applied to a wide variety of pattern recognition problems. In this theory, the first step in computing the next state of a neuron or in performing the next layer neural network computation involves the linear operation of multiplying neural values by their synaptic strengths and adding the results. A nonlinear activation function usually follows the linear operation in order to provide for nonlinearity of the network and set the next state of the neuron. In this paper we introduce a novel class of artificial neural networks, called morphological neural networks, in which the operations of multiplication and addition are replaced by addition and maximum (or minimum), respectively. By taking the maximum (or minimum) of sums instead of the sum of products, morphological network computation is nonlinear before possible application of a nonlinear activation function. As a consequence, the properties of morphological neural networks are drastically different than those of traditional neural network models. The main emphasis of the research presented here is on morphological associative memories. We examine the computing and storage capabilities of morphological associative memories and discuss differences between morphological models and traditional semilinear models such as the Hopfield net.

  16. Associative asymmetry of compound words.

    Science.gov (United States)

    Caplan, Jeremy B; Boulton, Kathy L; Gagné, Christina L

    2014-07-01

    Early verbal-memory researchers assumed participants represent memory of a pair of unrelated items with 2 independent, separately modifiable, directional associations. However, memory for pairs of unrelated words (A-B) exhibits associative symmetry: a near-perfect correlation between accuracy on forward (A →?) and backward (?← B) cued recall. This was viewed as arguing against the independent-associations hypothesis and in favor of the hypothesis that associations are remembered as holistic units. Here we test the Holistic Representation hypothesis further by examining cued recall of compound words. If we suppose preexisting words are more unitized than novel associations, the Holistic Representation hypothesis predicts compound words (e.g., ROSE BUD) will have a higher forward-backward correlation than novel compounds (e.g., BRIEF TAX). We report the opposite finding: Compound words, as well as noncompound words, exhibited less associative symmetry than novel compounds. This challenges the Holistic Representation account of associative symmetry. Moreover, preexperimental associates (positional family size) influenced associative symmetry-but asymmetrically: Increasing family size of the last constituent increasing decoupled forward and backward recall, but family size of the 1st constituent had no such effect. In short, highly practiced, meaningful associations exhibit associative asymmetry, suggesting associative symmetry is not diagnostic of holistic representations but, rather, is a characteristic of ad hoc associations. With additional learning, symmetric associations may be replaced by directional, independently modifiable associations as verbal associations become embedded within a rich knowledge structure.

  17. Pancytopenia associated with clonazepam

    Directory of Open Access Journals (Sweden)

    Hsueh Chung-Tsen

    2010-07-01

    Full Text Available Abstract We report a case of a 48-year-old Chinese female with end-stage renal disease and chronic anemia on hemodialysis. Clonazepam was prescribed for myoclonus disorder two weeks prior to her hospitalization. Subsequently, she was hospitalized for neutropenic fever with thrombocytopenia and worsening anemia. Bone marrow examination demonstrated a markedly hypocellular marrow (10-20% total cellularity. Clonazepam was discontinued, with gradual improvement of thrombocytopenia, and neutropenia in 1-2 weeks. To our knowledge, this is the first reported case of pancytopenia associated with clonazepam. We recommend patients taking clonazepam to be monitored with regular complete blood count to check for clinically significant pancytopenia or thrombocytopenia.

  18. TILLING and Associated Technologies

    Institute of Scientific and Technical Information of China (English)

    Trevor Wang; Cristobal Uauy; Brad Till; Chun-Ming Liu

    2010-01-01

    @@ As part of a collaboration between the John Innes Centre(JIC),Norwich,UK and the Centre for Signal Transduction and Metabolomics(C-STM)at the Institute of Botany(IOB),the Chinese Academy of Sciences,Beijing,a workshop on 'TILLING and Associated Technologies' was held at the IOB on 15-16 April 2010.Through sponsorship from the UK Biotechnology and Biological Sciences Research Council(BBSRC),Resarch Councils UK,China Office,and the Transgenic Research Project of China,experts were drawn from the USA,Europe and China to present their latest information on technology development for targeted single nucleotide polymorphism(SNP)detection to over 60 registered participants.

  19. HIV-Associated Tuberculosis

    Directory of Open Access Journals (Sweden)

    Kogieleum Naidoo

    2011-01-01

    Full Text Available The intersecting HIV and Tuberculosis epidemics in countries with a high disease burden of both infections pose many challenges and opportunities. For patients infected with HIV in high TB burden countries, the diagnosis of TB, ARV drug choices in treating HIV-TB coinfected patients, when to initiate ARV treatment in relation to TB treatment, managing immune reconstitution, minimising risk of getting infected with TB and/or managing recurrent TB, minimizing airborne transmission, and infection control are key issues. In addition, given the disproportionate burden of HIV in women in these settings, sexual reproductive health issues and particular high mortality rates associated with TB during pregnancy are important. The scaleup and resource allocation to access antiretroviral treatment in these high HIV and TB settings provide a unique opportunity to strengthen both services and impact positively in meeting Millennium Development Goal 6.

  20. Transfusion associated circulatory overload

    Directory of Open Access Journals (Sweden)

    Naveen Agnihotri

    2014-01-01

    Full Text Available Transfusion associated circulatory overload (TACO is an established, but grossly under diagnosed and underreported complication of blood transfusion. We present the case of a 46-year-old diabetic and hypertensive patient admitted to our hospital for recurrent episodes of urinary retention. Over initial 3 days of the admission, the patient received multiple units of packed red blood cells (RBC and fresh frozen plasma, uneventfully. However, the patient developed signs and symptoms suggestive of TACO with only small amount of the 4 th unit of RBC. The patient had to be shifted to the Intensive Care Unit for further management of this complication. Etiology of TACO is more complex than a mere circulatory overload and is still not completely understood. TACO leads to a prolonged hospital stay and morbidity in the patients developing this complication. TACO thus needs to be suspected in patients at risk for this complication.

  1. Sepsis-Associated Coagulopathy

    Directory of Open Access Journals (Sweden)

    Scarlatescu Ecaterina

    2016-10-01

    Full Text Available Systemic inflammatory activation in sepsis often leads to coagulation activation, but the relationship is bilateral, as coagulation also modulates the inflammatory response. This close associate has significant consequences for the pathogenesis of microvascular thrombosis and organ dysfunction in sepsis. While coagulation activation can be beneficial for immune defense, it can also be detrimental once it becomes widespread and uncontrolled. The knowledge of the pathophysiologic mechanisms involved in the interaction between infection and coagulation may lead to the better timing for the administration of targeted antithrombotic therapies in septic patients. This brief review highlights the pathophysiologic pathways leading to the prothrombotic state in sepsis and the mechanisms that play a role in the interaction between infection and coagulation.

  2. Urolithiasis associated with topiramate

    Directory of Open Access Journals (Sweden)

    Scott Eggener

    2004-02-01

    Full Text Available OBJECTIVE: Topiramate is a sulfamate-substituted monosaccharide anticonvulsant used as adjunctive therapy for intractable refractory seizures. It is report a case of topiramate-induced urolithiasis. CASE REPORT: A 35-year-old man presented with acute, right-sided, colicky flank pain. He denied hematuria or dysuria. He was in use of phenytoin, risperidone, phenobarbital, and topiramate. The total daily dose of topiramate was 375 mg. A CT scan showed a 7 x 1 mm curvilinear density at the right ureterovesical junction with proximal hydrouretronephrosis. He was managed with rigid ureteroscopic stone extraction and the calculus metabolic analysis revealed the stone was composed of carbonate apatite (70%, calcium oxalate dihydrate (20%, and calcium oxalate monohydrate (10%. COMMENTS: The present case typifies many features of topiramate-induced urolithiasis. Those who care for patients with urinary stone disease should be aware of this association.

  3. Korean Dermatological Association.

    Science.gov (United States)

    Ro, B I

    1998-12-01

    The Korean Dermatological Association (KDA) was founded on October 27, 1945. The first annual meeting was held on November 15, 1947, and meetings have been held twice a year since 1975. The KDA 50th Annual Spring Meeting was on April 15-16, 1998. Korean Journal of Dermatology, the official journal of the KDA, was first published in 1960 and has been published bimonthly since 1978. Annals of Dermatology (Seoul), the English journal, was first published in 1989 and has been published quarterly since 1995. The American residency and specialty board system was introduced in 1954. Board specialty examination of dermatology candidates by the KDA requires four years of residency. Three hundred and twenty residents are now in the training course in the fifty-nine resident training approved hospitals this year. KDA has seven regional dermatological societies; Seoul, Pusan, Taegu, Honam, Chungchong, Jeonbuk, and Kangwon. KDA has had eleven research subcommittees since 1981. There are two associated societies of the KDA; the Korean Society for Investigative Dermatology was founded in 1991, and the Korean Society for Medical Mycology was founded in 1994. The Korea-Japan Joint Meeting of Dermatology has been held every two years since 1979 and the Korea-China Joint Meeting of Dermatology and Mycology has been held since 1996. About three hundred papers were presented at the 49th Annual Autumn Meeting on October 21-23, 1997. These included special lectures, invited lectures, educational lectures, oral presentations, and posters. About five hundred dermatologists participated in that meeting. KDA joined the International League of Dermatological Societies in 1973 with forty-seven members. There are around 1200 members of the KDA including 320 residents in 1998.

  4. Mechanical characterization and numerical modeling of a rotary X-ray anode; Caracterisation mecanique et simulation numerique d'une anode tournante de rayons X

    Energy Technology Data Exchange (ETDEWEB)

    Lemarchand, G

    2003-04-15

    This works deals with the design of light rotary anodes used for the generation of X-rays in medical scanners. Such anodes are made of graphite coated with tungsten by low pressure plasma sputtering. The mechanical behaviour of these materials during intense thermo-mechanical solicitation has been studied. In a first step, the in-service conditions of solicitation are defined in terms of excitation frequency, temperature, deformation and deformation velocity. The analysis of used anodes has permitted to define the main modes of in-service damage. Tests were performed on small size samples over the complete temperature range between ambient temperature and 1800 deg. C. Carbon has shown a fragile elastic behaviour while tungsten has shown a more complex behaviour: elastic-fragile up to 400 deg. C, then plastic, and becoming creep sensible above 1200 deg. C. Original load paths have permitted to show the existence of an internal back-stress and a coupling between plastic and viscous deformations. The definition of an original phenomenological law of behaviour with a double inelastic, plastic and visco-plastic deformation and with an interaction term between both flow mechanisms has been necessary to describe the mechanical behaviour of tungsten. The cold-drawing generated by each flow is translated into kinematic variables. The numerical identification of the parameters has been performed using an optimizer coupled to a finite element code which simulates the flexural test. The obtained law has been validated by the experimental observation of paths for complex loads. This behaviour law has been finally used to simulate the conditions of use of a real anode. An axisymmetrical 2-D mesh has permitted to calculate the constraints generated by the post-annealing cooling, by one and several series of radiographies and finally by a complete cooling after use. The repetition of radiographies rapidly leads to stabilized cycles. The calculated stress levels are realistic and remain inferior to the rupture resistance of the materials. This simulation can already be industrially used to evaluate the influence of a change in the anode geometry or in the conditions of in-service constraints. (J.S.)

  5. Proposal of a numerical modeling of reactive flows in combustion chambers of turbojet engines; Proposition d`une modelisation numerique des ecoulements reactifs dans les foyers de turboreacteurs

    Energy Technology Data Exchange (ETDEWEB)

    Ravet, F. [Rouen Univ., 76 - Mont-Saint-Aignan (France)]|[SNECMA, 77 - Moissy-Cramayel (France); Baudoin, Ch.; Schultz, J.L. [SNECMA, 77 - Moissy-Cramayel (France)

    1996-12-31

    Simplifying hypotheses are required when combustion and aerodynamic phenomena are considered simultaneously. In this paper, a turbulent combustion model is proposed, in which the combustion chemistry is reduced to a single reaction. In this way, only two variables are needed to describe the problem and combustion can be characterized by the consumption of one of the two reactive species. In a first step, the instantaneous consumption rate is obtained using the Lagrangian form of the mass fraction equation of the species under consideration, and by considering the equilibrium state only. This state is determined in order to preserve the consistency with results that should be obtained using a complete kinetics scheme. In a second step, the average rate is determined using the instantaneous consumption term and a probabilistic density function. This model was tested on various configurations and in particular on an experimental main chamber and on a reheating chamber. Results indicate that this model could be used to predict temperature levels inside these combustion chambers. Other applications, like the prediction of pollutant species emission can be considered. (J.S.) 12 refs.

  6. Eulerian numerical simulation of gas-solid flows with several particles species; Modelisation numerique eulerienne des ecoulements gaz-solide avec plusieurs especes de particules

    Energy Technology Data Exchange (ETDEWEB)

    Patino-Palacios, G

    2007-11-15

    The simulation of the multiphase flows is currently an important scientific, industrial and economic challenge. The objective of this work is to improve comprehension via simulations of poly-dispersed flows and contribute the modeling and characterizing of its hydrodynamics. The study of gas-solid systems involves the models that takes account the influence of the particles and the effects of the collisions in the context of the momentum transfer. This kind of study is covered on the framework of this thesis. Simulations achieved with the Saturne-polyphasique-Tlse code, developed by Electricite de France and co-worked with the Institut de Mecanique des Fluides de Toulouse, allowed to confirm the feasibility of approach CFD for the hydrodynamic study of the injectors and dense fluidized beds. The stages of validation concern, on the one hand, the placement of the tool for simulation in its current state to make studies of validation and sensitivity of the models and to compare the numerical results with the experimental data. In addition, the development of new physical models and their establishments in the code Saturne will allow the optimization of the industrial process. To carry out this validation in a satisfactory way, a key simulation is made, in particular a monodisperse injection and the radial force of injection in the case of a poly-disperse flow, as well as the fluidization of a column made up of solid particles. In this last case, one approached three configurations of dense fluidized beds, in order to study the influence of the grid on simulations; then, one simulates the operation of a dense fluidized bed with which one characterizes the segregation between two various species of particles. The study of the injection of the poly-disperse flows presents two configurations; a flow Co-current gas-particle in gas (Case Hishida), and in addition, a poly-phase flow in a configuration of the jet type confined with zones of recirculation and stagnation (case Hercules). Numerical calculations were compared with the experimental data available and showed a satisfactory reproducibility of the hydrodynamic prediction of the multi-phasic flows. (author)

  7. Macroscopic numerical simulation model of multi-constituent fluid flows in porous medium; Modele macroscopique de simulation numerique d'ecoulements de fluides multiconstituants en milieu poreux

    Energy Technology Data Exchange (ETDEWEB)

    Wilbois, B.

    2003-07-01

    In this work, a new model is built which allows to take into consideration the overall mass transfer phenomena (in particular convection) taking place inside a mixture of n{sub c} constituents in a porous medium. This model should allow to foresee the quantitative composition of fluids in oil fields and also to improve the knowledge of the flow of different species inside mixtures. The overall physical phenomena taking place at oil fields is explained in the first chapter. Chapter 2 recalls some thermodynamical notions at the equilibrium and outside equilibrium. These notions, necessary to understand the forecasting methods used by petroleum geologists, are described in chapter 3. This chapter includes also a bibliographic study about the methods of simulation of mass and heat transfers in porous media. In chapter 4, using the thermodynamical relations of irreversible processes described in chapter 2, a new type of macroscopic model allowing to describe the overall phenomena analyzed is developed. The numerical method used to solve this new system of equations is precised. Finally, chapter 5 proposes a set of cases for the validation of the uncoupled phenomena and some qualitative examples of modeling of coupled phenomena. (J.S.)

  8. Numerical study of the atomic and electronic structure of some silicon grain boundaries; Etude numerique de la structure atomique et electronique de quelques joints de grains du silicium

    Energy Technology Data Exchange (ETDEWEB)

    Torrent, M

    1996-07-01

    This work contributes to the theoretical study of extended defects in covalent materials. The study is especially devoted to the tilt grain boundaries in silicon as a model material. The theoretical model is based on the self-consistent tight-binding approximation and is applied within two numerical techniques: the fast 'order N' density-matrix method and the diagonalization technique which allows the sampling of the reciprocal space. Total energy parameters of the model have been fitted in order to reproduce the silicon band structure (with a correct gap value) and the transferability of crystalline and mechanical properties of this material. A new type of boundary conditions is proposed and tested. These conditions, named 'ante-periodic' or 'Moebius', allow only one grain boundary per box instead of two and decrease the CPU time by a factor of two. The model is then applied to the study of the {sigma}=25 [001] (710) grain boundary. The results show the possible presence in this boundary of low energy non-reconstructed atomic structures which are electrically active. This confirms what had been suggested by some experimental observations. The same study is also performed for the {sigma}=13 [001] (510) grain boundary. In order to compare the intrinsic electrical activity in the previous grain boundaries with the one induced by impurities, a total energy parametrization for the silicon-nickel bond is achieved and used in preliminary calculations. Finally the two variants of the {sigma}=11 [011] (2-33) interface are studied, especially their respective interfacial energies. The result disagrees with previous calculations using phenomenological potentials. (author)

  9. Numerical simulation of Vlasov equation with parallel tools; Simulations numeriques de l'equation de Vlasov a l'aide d'outils paralleles

    Energy Technology Data Exchange (ETDEWEB)

    Peyroux, J

    2005-11-15

    This project aims to make even more powerful the resolution of Vlasov codes through the various parallelization tools (MPI, OpenMP...). A simplified test case served as a base for constructing the parallel codes for obtaining a data-processing skeleton which, thereafter, could be re-used for increasingly complex models (more than four variables of phase space). This will thus make it possible to treat more realistic situations linked, for example, to the injection of ultra short and ultra intense impulses in inertial fusion plasmas, or the study of the instability of trapped ions now taken as being responsible for the generation of turbulence in tokamak plasmas. (author)

  10. Deterministic sensitivity analysis for the numerical simulation of contaminants transport; Analyse de sensibilite deterministe pour la simulation numerique du transfert de contaminants

    Energy Technology Data Exchange (ETDEWEB)

    Marchand, E

    2007-12-15

    The questions of safety and uncertainty are central to feasibility studies for an underground nuclear waste storage site, in particular the evaluation of uncertainties about safety indicators which are due to uncertainties concerning properties of the subsoil or of the contaminants. The global approach through probabilistic Monte Carlo methods gives good results, but it requires a large number of simulations. The deterministic method investigated here is complementary. Based on the Singular Value Decomposition of the derivative of the model, it gives only local information, but it is much less demanding in computing time. The flow model follows Darcy's law and the transport of radionuclides around the storage site follows a linear convection-diffusion equation. Manual and automatic differentiation are compared for these models using direct and adjoint modes. A comparative study of both probabilistic and deterministic approaches for the sensitivity analysis of fluxes of contaminants through outlet channels with respect to variations of input parameters is carried out with realistic data provided by ANDRA. Generic tools for sensitivity analysis and code coupling are developed in the Caml language. The user of these generic platforms has only to provide the specific part of the application in any language of his choice. We also present a study about two-phase air/water partially saturated flows in hydrogeology concerning the limitations of the Richards approximation and of the global pressure formulation used in petroleum engineering. (author)

  11. Asymptotic study and numerical simulation of laser wave propagation in an inhomogeneous medium; Etude asymptotique et simulation numerique de la propagation laser en milieu inhomogene

    Energy Technology Data Exchange (ETDEWEB)

    Doumic, M

    2005-05-15

    To simulate the propagation of a monochromatic laser beam in a medium, we use the paraxial approximation of the Klein-Gordon (in the time-varying problem) and of the Maxwell (in the non time-depending case) equations. In a first part, we make an asymptotic analysis of the Klein-Gordon equation. We obtain approximated problems, either of Schroedinger or of transport-Schroedinger type. We prove the existence and uniqueness of a solution for these problems, and estimate the difference between it and the exact solution of the Klein-Gordon equation. In a second part, we study the boundary problem for the advection Schroedinger equation, and show what the boundary condition must be so that the problem on our domain should be the restriction of the problem in the whole space: such a condition is called a transparent or an absorbing boundary condition. In a third part, we use the preceding results to build a numerical resolution method, for which we prove stability and show some simulations. (author)

  12. Some numerical methods for two-fluid two-phase flows in oil pipes; Quelques methodes numeriques pour les ecoulements diphasiques bi-fluide en conduites petrolieres

    Energy Technology Data Exchange (ETDEWEB)

    Masella, J.M.

    1997-05-29

    This thesis is devoted to the numerical simulation of some two-fluid models describing gas-liquid two-phase flow in pipes. The numerical models developed here can be more generally used in the modelling of a wide class of physical models which can be put under an hyperbolic form. We introduce first two isothermal two-fluid models, composed of a mass balance equation and a momentum equation written in each phase, describing respectively a stratified two-phase flow and a dispersed two-phase flow. These models are hyperbolic under some physical assumptions and can be written under a nonconservative vectorial system. We define and analyse a new numerical finite volume scheme (v{integral}Roe) founded on a linearized Riemann solver. This scheme does not need any analytical calculation and gives good results in the tracking of shocks. We compare this new scheme with the classical Roe scheme. Then we propose and study some numerical models, with and without flux splitting method, which are adapted to the discretization of the two-fluid models. This numerical models are given by a finite volume integration of the equations, and lean on the v{integral} scheme. In order to reducing cpu time, due to the low Mach number of two-phase flows, acoustic waves are implicit. Afterwards we proposed a discretization of boundary conditions, which allows the generation of transient flows in pipe. Some numerical academic and more physical tests show the good behaviour of the numerical methods. (author) 77 refs.

  13. Theoretical and numerical studies of Rayleigh-Taylor instabilities in magnetized plasmas; Etude theorique et numerique des instabilites Rayleigh-Taylor en plasmas magnetises

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, A.A

    2001-06-01

    The instabilities of Rayleigh-Taylor type are considered in the thesis. The topic of the thesis was inspired by recent advances in the physics of plasma compression, especially with the aid of systems like Z-pinch. Rayleigh-Taylor instability (RTI) plays an important role in the evolution of magnetized plasmas in these experiments, as well as in stellar plasmas and classic fluids. For the phenomena concerning the nuclear fusion the RTI is very often the factor limiting the possibility of compression. In the current work we try to examine in detail the characteristic features of the instabilities of this type in order to eliminate their detrimental influence. In this thesis we are studying both the general case of the 'classic' Rayleigh-Taylor instability (in incompressible fluids) and more specific cases of the instabilities of Rayleigh-Taylor type in magnetized plasmas, in the liners or wire array implosions etc. We have studied the influence of the Hall diffusion of magnetic field on the growth rate of the instability. We have obtained in this work a self-similar solution for the widening of the initial profile of the magnetic field and for the wave of the penetration of magnetic field. After that the subsequent evolution of the magnetic field in plasma opening switches (POS) has been examined. We have shown the possibility of the existence of a strong rarefaction wave for collisional and non-collisional cases. This wave can explain the phenomenon of the opening of POS. The effect of the suppression of Rayleigh-Taylor instability by forced oscillations of the boundary between two fluids permits us to propose some ideas for the experiments of inertial fusion. We have considered the general case of the instability, in other words, two incompressible viscous superposed fluids in a gravitational field. We have obtained an exact analytical expression for the growth rate and then we have analyzed the influence of the parameters of external 'pumping' on the instability. These results can be applied to a wide range of systems, starting from classic hydrodynamics and up to astrophysical plasmas. The scheme of wire arrays has become recently a very popular method to obtain a high power X-radiation or for a high quality implosion in Z-pinches. The experimental studies have demonstrated that the results of implosion are much better for the case of multiple thin wires situated cylindrically than in a usual liner scheme. We have examined the problem modeling the stabilization of Rayleigh-Taylor instability for a wire array system. The reason for instability suppression is the regular spatial modulation of the surface plasma-magnetic field (in the vacuum). This modulation is created by the explosions of solid wires and by subsequent plasma evolution. We have also examined the coupling of the instability modes that takes place in the presence of the magnetic field and this study shows that the spatial surface modulation can effectively diminish the growth rate of the considered instability. (author)

  14. Theoretical and numerical study of Rayleigh-Taylor instabilities in magnetized plasmas; Etude theorique et numerique des instabilites rayleigh-taylor en plasmas magnetises

    Energy Technology Data Exchange (ETDEWEB)

    Andrei, A. Ivanov

    2001-06-15

    In this thesis we're studying both the general case of the 'classic' Rayleigh-Taylor instability (in incompressible fluids) and more specific cases of the instabilities of Rayleigh-Taylor type in magnetized plasmas, in the liners or wire array implosions etc. We have studied the influence of the Hall diffusion of magnetic field on the growth rate of the instability. We have obtained in this work a self-similar solution for the widening of the initial profile of the magnetic field and for the wave of the penetration of magnetic field. After that the subsequent evolution of the magnetic field in plasma opening switches (POS) has been examined. We have shown the possibility of the existence of a strong rarefaction wave for collisional and non-collisional cases. This wave can explain the phenomenon of the opening of POS. The effect of the suppression of Rayleigh-Taylor instability by forced oscillations of the boundary between two fluids permits us to propose some ideas for the experiments of inertial fusion. We have considered the general case of the instability, in other words - two incompressible viscous superposed fluids in a gravitational field. We have obtained an exact analytical expression for the growth rate and then we have analyzed the influence of the parameters of external 'pumping' on the instability. These results can be applied to a wide range of systems, starting from classic hydrodynamics and up to astrophysical plasmas. The scheme of wire arrays has become recently a very popular method to obtain a high power X-radiation or for a high quality implosion in Z-pinches. The experimental studies have demonstrated that the results of implosion are much better for the case of multiple thin wires situated cylindrically than in a usual liner scheme. We have examined the problem modeling the stabilization of Rayleigh-Taylor instability for a wire array system. The reason for instability suppression is the regular spatial modulation of the surface plasma-magnetic field (in the vacuum). This modulation is created by the explosions of solid wires and by subsequent plasma evolution. We have also examined the coupling of the instability modes that takes place in the presence of the magnetic field and this study shows that the spatial surface modulation can effectively diminish the growth rate of the considered instability. (author)

  15. Interest of numerical dosimetry in radiation protection: mean of substitution or measurements consolidation?; Interet de la dosimetrie numerique en radioprotection: moyen de substitution ou de consolidation des mesures?

    Energy Technology Data Exchange (ETDEWEB)

    Lahaye, T.; Chau, Q. [Institut de Radioprotection et de Surete Nucleaire (IRSN/DPHD/SDOS), Service Dosimetrie, 92 - Fontenay-aux-Roses (France); Ferragut, A.; Gillot, J.Y. [SAPHYMO, 91 - Massy (France)

    2003-07-01

    The use of calculation codes allows to reduce the costs and the time limits. These codes brings to operators elements to reinforce their projected dosimetry. In the cases of accidental overexposure, the numerical dosimetry comes in complement of clinical and biological investigations to give an estimation as precise as possible of the received dose. For particular situations where it does not exist an adapted instrumentation, the numerical dosimetry can substitute to conventional techniques used by regulatory dosimetry (project for aviation personnel). (N.C.)

  16. Modelling and numerical simulation of liquid-vapor phase transitions; Modelisation et simulation numerique des transitions de phase liquide-vapeur

    Energy Technology Data Exchange (ETDEWEB)

    Caro, F

    2004-11-15

    This work deals with the modelling and numerical simulation of liquid-vapor phase transition phenomena. The study is divided into two part: first we investigate phase transition phenomena with a Van Der Waals equation of state (non monotonic equation of state), then we adopt an alternative approach with two equations of state. In the first part, we study the classical viscous criteria for selecting weak solutions of the system used when the equation of state is non monotonic. Those criteria do not select physical solutions and therefore we focus a more recent criterion: the visco-capillary criterion. We use this criterion to exactly solve the Riemann problem (which imposes solving an algebraic scalar non linear equation). Unfortunately, this step is quite costly in term of CPU which prevent from using this method as a ground for building Godunov solvers. That is why we propose an alternative approach two equations of state. Using the least action principle, we propose a phase changing two-phase flow model which is based on the second thermodynamic principle. We shall then describe two equilibrium submodels issued from the relaxations processes when instantaneous equilibrium is assumed. Despite the weak hyperbolicity of the last sub-model, we propose stable numerical schemes based on a two-step strategy involving a convective step followed by a relaxation step. We show the ability of the system to simulate vapor bubbles nucleation. (author)

  17. The transition radiation. I: numerical study of the angular and spectral distributions; Le rayonnement de transition optique. I: etude numerique des distributions angulaires et spectrales

    Energy Technology Data Exchange (ETDEWEB)

    Couillaud, Ch.; Haouat, G

    1999-07-01

    The optical transition radiation (OTR) is extensively used since many years as a beam visualisation tool on electron accelerators and serves to monitor the beam during its transport adjustment. Its spatial and temporal characteristics make it very attractive as a diagnostic tool and allow measurements of the beam energy and transverse and longitudinal emittances. We present a numerical study of the transition radiation process in the optical region of the radiated spectrum (OTR) and in the higher part (XTR). Spatial and spectral properties are described. They are used to describe experimental observations performed on the ELSA electron-beam facility. An analytical description of the angular distributions of visible radiation emitted by birefringent targets, used as OTR sources, is also proposed. We also analyze interference phenomena between two OTR sources and show the advantage of using this interferometer as a diagnostic tool for tenth MeV electron accelerators. At last, we present an analytical model allowing to design a soft X-ray source to be installed on the ELSA facility and using either a multi-foil stack or a multilayer of two materials of different permittivities. (authors)

  18. Modeling and numerical analysis of non-equilibrium two-phase flows; Modelisation et analyse numerique des ecoulements diphasiques en desequilibre

    Energy Technology Data Exchange (ETDEWEB)

    Rascle, P.; El Amine, K. [Electricite de France (EDF), Direction des Etudes et Recherches, 92 - Clamart (France)

    1997-12-31

    We are interested in the numerical approximation of two-fluid models of nonequilibrium two-phase flows described by six balance equations. We introduce an original splitting technique of the system of equations. This technique is derived in a way such that single phase Riemann solvers may be used: moreover, it allows a straightforward extension to various and detailed exchange source terms. The properties of the fluids are first approached by state equations of ideal gas type and then extended to real fluids. For the construction of numerical schemes , the hyperbolicity of the full system is not necessary. When based on suitable kinetic unwind schemes, the algorithm can compute flow regimes evolving from mixture to single phase flows and vice versa. The whole scheme preserves the physical features of all the variables which remain in the set of physical states. Several stiff numerical tests, such as phase separation and phase transition are displayed in order to highlight the efficiency of the proposed method. The document is a PhD thesis divided in 6 chapters and two annexes. They are entitled: 1. - Introduction (in French), 2. - Two-phase flow, modelling and hyperbolicity (in French), 3. - A numerical method using upwind schemes for the resolution of two-phase flows without exchange terms (in English), 4. - A numerical scheme for one-phase flow of real fluids (in English), 5. - An upwind numerical for non-equilibrium two-phase flows (in English), 6. - The treatment of boundary conditions (in English), A.1. The Perthame scheme (in English) and A.2. The Roe scheme (in English). 136 refs. This document represents a PhD thesis in the speciality Applied Mathematics presented par Khalid El Amine to the Universite Paris 6.

  19. Thermal design of horizontal tube boilers. Numerical and experimental investigation; Modelisation thermique de bouilleurs a tubes horizontaux. Etude numerique et validation experimentale

    Energy Technology Data Exchange (ETDEWEB)

    Roser, R.

    1999-11-26

    This work concerns the thermal design of kettle reboilers. Current methods are highly inaccurate, regarded to the correlations for external heat transfer coefficient at one tube scale, as well as to two-phase flow modelling at boiler scale. The aim of this work is to improve these thermal design methods. It contains an experimental investigation with typical operating conditions of such equipment: an hydrocarbon (n-pentane) with low mass flux. This investigation has lead to characterize the local flow pattern through void fraction measurements and, from this, to develop correlations for void fraction, pressure drop and heat transfer coefficient. The approach is original, since the developed correlations are based on the liquid velocity at minimum cross section area between tubes, as variable characterizing the hydrodynamic effects on pressure drop and heat transfer coefficient. These correlations are shown to give much better results than those suggested up to now in the literature, which are empirical transpositions from methods developed for inside tube flows. Furthermore, the numerical code MC3D has been applied using the correlations developed in this work, leading to a modeling of the two-phase flow in the boiler, which is a significant progress compared to current simplified methods. (author)

  20. Numerical study of a power transformer cooling by a directed flow; Etude numerique du refroidissement d'un transformateur electrique de puissance par un ecoulement dirige

    Energy Technology Data Exchange (ETDEWEB)

    Nadim El Wakil; Jacques Padet [Laboratoire de Thermomecanique UTAP, Universite de Reims Champagne Ardenne Faculte des Sciences, B.P. 1039, 51687 Reims, (France); Nelu-Cristian Chereches; Nicolae Taranu [Faculte de Genie Civil, Universite Technique Gh. Asachi de Iasi 38, Lascar Catargi, 700107 Iasi, (Romania)

    2005-07-01

    In this article the fluid flow and the heat transfer by mixed convection are analyzed inside a three - phase power transformer. Avoiding the hot spots in a power transformer is a determining factor for its preservation and its good functioning. In order to ensure an efficient cooling, a directed flow is a good solution inside a multichannel system. The modeling was made on the middle column of the power transformer where the core is wounded around by two windings inside an axisymmetric geometry. The entrance and the exit of the fluid are located respectively at the bottom and at the top of the core axis. Different geometric configurations were conceived and studied in order to improve the heat transfer and the cooling of the power transformer. (authors)

  1. Experimental and numerical study of the active control of jets inside combustion chambers; Etude experimentale et numerique du controle actif de jets dans des chambres de combustion

    Energy Technology Data Exchange (ETDEWEB)

    Faivre, V.

    2003-12-15

    Combustion instabilities occur when the flame heat release couples with the acoustic waves propagating in the combustion chamber. This phenomenon can lead to strong vibrations and noise but also, sometimes, to the complete combustion device failure. That is the reason why so many studies focus on the control of those instabilities. The method chosen in this study consists in an active control device (or set of actuators) having a strong effect on the mixing of the burner exhaust flow with the ambient fluid. The model configuration studied consists in a non reactive jet of air controlled by four small tangential secondary jets. Experiments have been carried out to optimize the control device geometry. The configuration identified as the most efficient, in terms of mixing enhancement, has been simulated through Large Eddy Simulations (LES). The objective of the numerical part of the present work is double. First, the numerical simulations provide a better understanding of the phenomena occurring when the control is on. Then, it is shown that LES can be considered as a tool to predict the effects of a control device on a flow. (author)

  2. Spectral methods for the uncertainties propagation in numerical simulation; Methodes spectrales robustes pour la propagation d'incertitudes en simulation numerique

    Energy Technology Data Exchange (ETDEWEB)

    Crestaux, Th. [CEA Saclay, Dept. Modelisation de Systemes et Structures (DEN/DANS/DM2S/SFME), 91 - Gif sur Yvette (France)

    2008-07-01

    The context of this thesis is the development of the numerical simulation in industrial processes. It aims to study and develop methods allowing a decrease of the numerical cost of calculi of Chaos Polynomials development. The implementing concerns problems of high stochastic dimension and more particularly the transport model of radionuclides in radioactive wastes disposal. (A.L.B.)

  3. Flying Qualities Flight Testing of Digital Flight Control Systems. Flight Test Techniques Series - Volume 21 (les Essais en vol des performances des systemes de ommande de vol numeriques)

    Science.gov (United States)

    2001-12-01

    et leur sécurité. Note de traduction : l’auteur insiste lourdement dans le 2ème paragraphe sur la préparation des essais et l’analyse des...feedback loop is readily apparent. As an example, a roll-rate feedback to the aileron is a good indication that the roll mode required augmentation. The...impacts of roll-rate feedback to the aileron on this mode are well understood from the classical design theory. Newer or so-called modern design

  4. Numerical simulation of inertial two-phase flow in heterogenous media; Simulation Numerique d'Ecoulement Diphasique Inertiel en Milieu Poreux Heterogene

    Energy Technology Data Exchange (ETDEWEB)

    Ali Akbar ABBASIAN ARANI; Didier LASSEUX; Azita AHMADI [TREFLE-ENSAM, UMR CNRS 8508, Esplanade des Arts et Metiers 33405 Talence Cedex, (France)

    2005-07-01

    In this work, we present the development of a 3 D numerical tool for simulation of non-Darcy two-phase flow in heterogeneous porous media. The physical model selected is the generalized Darcy-Forchheimer model. A validation is performed first by comparing numerical results with a semi-analytical solution of the Buckley-Leverett type. Secondly, numerical results obtained on 1 D and 2 D heterogeneous configurations are presented and we highlight the importance of the inertial terms according to a Reynolds number of the flow. (authors)

  5. Theoretical and numerical study of free shear flows with large density ratio; Etude theorique et numerique des ecoulements cisailles libres a masse volumique fortement variable

    Energy Technology Data Exchange (ETDEWEB)

    Lardjane, N.

    2002-05-15

    The subject of this work concerns the application of large-eddy simulation to the mixing of two fluids with different thermodynamical properties. Numerical errors in the discretization of Navier-Stokes equations and their interaction with sub-grid models are investigated on a self decaying isotropic homogeneous turbulence. A high resolution numerical code is then developed for the simulation of binary mixing layers. Reduction of early acoustic waves amplitude is achieved by use of a temporal self-similar initial condition. The relative magnitude of sub-grid terms arising from filtered equations is investigated on explicit filtering of direct numerical simulation results of temporal N{sub 2}/O{sub 2} and H{sub 2}/O{sub 2} mixing layers. Implicit closure (MILES) is then evoked on the basis of WENO schemes. (author)

  6. Waves and particles in the Fermi accelerator model. Numerical simulation; Ondes et particules dans le modele de l`accelerateur de Fermi. Simulation numerique

    Energy Technology Data Exchange (ETDEWEB)

    Meplan, O.

    1996-01-01

    This thesis is devoted to a numerical study of the quantum dynamics of the Fermi accelerator which is classically chaotic: it is particle in a one dimensional box with a oscillating wall. First, we study the classical dynamics: we show that the time of impact of the particle with the moving wall and its energy in the wall frame are conjugated variables and that Poincare surface of sections in these variables are more understandable than the usual stroboscopic sections. Then, the quantum dynamics of this systems is studied by the means of two numerical methods. The first one is a generalization of the KKR method in the space-time; it is enough to solve an integral equation on the boundary of a space-time billiard. The second method is faster and is based on successive free propagations and kicks of potential. This allows us to obtain Floquet states which we can on one hand, compare to the classical dynamics with the help of Husimi distributions and on the other hand, study as a function of parameters of the system. This study leads us to nice illustrations of phenomenons such as spatial localizations of a wave packet in a vibrating well or tunnel effects. In the adiabatic situation, we give a formula for quasi-energies which exhibits a phase term independent of states. In this regime, there exist some particular situations where the quasi-energy spectrum presents a total quasi-degeneracy. Then, the wave packet energy can increase significantly. This phenomenon is quite surprising for smooth motion of the wall. The third part deals with the evolution of a classical wave in the Fermi accelerator. Using generalized KKR method, we show a surprising phenomenon: in most of situations (so long as the wall motion is periodic), a wave is localized exponentially in the well and its energy increases in a geometric way. (author). 107 refs., 66 figs., 5 tabs. 2 appends.

  7. Radiography of scoliosis: comparative dosimetry between conventional technique and digital fluorography; Radiographie des scolioses: dosimetrie comparee entre la technique conventionnelle et la fluorographie numerique

    Energy Technology Data Exchange (ETDEWEB)

    Gorincour, G.; Paris, M.; Aschero, A.; Bourliere, B.; Devred, P.; Petit, P. [Hopital Timone-Enfants, Service de Radiologie Pediatrique, 13 - Marseille (France); Barrau, K.; Auquier, P. [Faculte de Medecine de Marseille, Service de Sante Publique, 13 - Marseille (France); Waultier, S.; Bourrelly, M.; Mundler, O. [Hopital Timone-Enfants, Service de Medecine Nucleaire, 13 - Marseille (France); Viehweger, E.; Jouve, J.L.; Bollini, G. [Hopital Timone-Enfants, Service de Chirurgie Orthopedique, 13 - Marseille (France)

    2007-03-15

    Objective. Compare the irradiation delivered in conventional radiography and digital radiography by image intensifier during a scoliosis workup. Patients and Methods. Our prospective randomized study included 105 patients, all of whom were identified according to socio-demographic parameters as well as criteria evaluating the quality of the full front spinal x-ray at PA incidence. The entry dose at the scapula and the exit dose in inter-orbital, thyroid, mammary, and hypo-gastric projection was measured by thermoluminescent dosimeters. Results. The results of 71 girls and 28 boys, aged a mean 13.8 years with a mean weight of 47 kg were analyzed. At equal image quality, the entry dose was not significantly different between the two techniques; the mean exit dose reduction was 64% during digital acquisition. This reduction involved the inter-orbital (162%), mammary (43%), and thyroid (309%) regions. However, this system is more irradiating in the hypo-gastric region (34%). Conclusion. The dosimetric evaluation of the different imaging techniques used to explore the entirety of the spine should be part of radiologists' quality standard used to document their work and their choices. (authors)

  8. Developpement numerique et implementation experimentale d'une methodologie d'identification de l'equation de dispersion dans les structures aeronautiques

    Science.gov (United States)

    Egreteau, Thomas

    Ce document contient les objectifs, le cheminement suivi et les résultats obtenus d'un projet visant à identifier le nombre d'onde sur différents types de plaques représentatives de ce qui est utilise en aéronautique. Dans une première partie, on y définit les enjeux du sujet, liés au domaine aéronautique et le contexte dans lequel ce projet se déroule. A la suite de quoi, est exposée la revue de l'état de l'art sur les méthodes existantes de mesure du nombre d'onde. Le projet en lui-même est ensuite défini avec un objectif principal fixé qui est de mesurer le nombre d'onde d'une plaque à partir de mesures vibratoires. Pour cela deux méthodes seront utilisées; la méthode de différence de phase permettant d'effectuer la mesure sur les plaques simples ou composites et la méthode du passage dans le domaine des nombres d'onde permettant cette même mesure sur des plaques plus complexes (plaque épaisse ou raidie par exemple). Pour chaque méthode, un cheminement équivalent est utilisé. Dans un premier temps, on développe et implémente la méthode choisie de manière basique, puis on réalise l'étude paramétrique permettant de connaitre les conditions optimales de fonctionnement des deux méthodes, enfin une validation expérimentale est réalisée. Dans ce document, les deux méthodes seront aussi comparées pour en déduire dans quelles conditions il faut utiliser l'une ou l'autre des méthodes. La méthode de la différence de phase donne de bons résultats dans le cas de plaques simples et composites si on est capable d'exciter suffisamment toutes la gamme de fréquence. La méthode du passage dans le domaine des nombres d'onde quant à elle est apte à mesurer le nombre d'onde sur tous types de plaques et dans toutes les directions si la zone de mesure est suffisamment grande. Mots-clés : Nombre d'onde, plaques, différence de phase, domaine des nombre d'onde, transformée de Fourier spatiale, Définition de projet de recherche.

  9. Global sensitivity analysis of thermomechanical models in modelling of welding; Analyse de sensibilite globale de modeles thermomecanique de simulation numerique du soudage

    Energy Technology Data Exchange (ETDEWEB)

    Petelet, M

    2008-07-01

    Current approach of most welding modellers is to content themselves with available material data, and to chose a mechanical model that seems to be appropriate. Among inputs, those controlling the material properties are one of the key problems of welding simulation: material data are never characterized over a sufficiently wide temperature range. This way to proceed neglect the influence of the uncertainty of input data on the result given by the computer code. In this case, how to assess the credibility of prediction? This thesis represents a step in the direction of implementing an innovative approach in welding simulation in order to bring answers to this question, with an illustration on some concretes welding cases.The global sensitivity analysis is chosen to determine which material properties are the most sensitive in a numerical welding simulation and in which range of temperature. Using this methodology require some developments to sample and explore the input space covering welding of different steel materials. Finally, input data have been divided in two groups according to their influence on the output of the model (residual stress or distortion). In this work, complete methodology of the global sensitivity analysis has been successfully applied to welding simulation and lead to reduce the input space to the only important variables. Sensitivity analysis has provided answers to what can be considered as one of the probable frequently asked questions regarding welding simulation: for a given material which properties must be measured with a good accuracy and which ones can be simply extrapolated or taken from a similar material? (author)

  10. Mathematical and numerical analysis of hyper-elastic systems and introduction of plasticity; Analyse mathematique et numerique de systemes hyperelastiques et introduction de la plasticite

    Energy Technology Data Exchange (ETDEWEB)

    Kluth, G

    2008-12-15

    The goal is to model mathematically and numerically the dynamic phenomenons for solids in finite plasticity. We suggest a model that we call hyper-elasto-plastic based on hyper-elastic systems of conservation laws and on the use of an equation of state that we have constructed so as to achieve the plastic yield criterion of Von Mises. This model gives exact (analytic) solutions with shock split to flyer-plate experiments. The mathematical analysis of this model is done (hyperbolicity, characteristic fields, involutions and entropy). In the numerical part, we give 1D and 2D Lagrangian schemes which satisfy an entropy criterion. Moreover, thanks to a special discretization of the equations on deformation gradient, we satisfy some discrete involutions. In this work, the degeneracy of the solid model into hydrodynamic models is studied at the continuous level, and achieved at the numerical one. On different problems, we show the validity of our model and our numerical schemes. (author)

  11. Ascouf: an industrial software for the engineering of nuclear facilities in operation; Ascouf: un outil numerique industriel pour l`ingenierie nucleaire du parc en exploitation

    Energy Technology Data Exchange (ETDEWEB)

    Genette, P.; Martelet, B. [Electricite de France (EDF), 69 - Villeurbanne (France). Div. Mecanique des Structures du Septen; Debost-Eymart, I. [Electricite de France (EDF), 92 - Clamart (France). Dept. Mecanique et Modeles Numeriques

    1998-10-01

    The ASCOUF software has been developed par EDF to facilitate the quick analysis of defects contained in pipes or elbows of the primary loop. This preprocessing tool of Code Aster, the structural analysis finite element code of EDF, has been used to carry out, with an increase of productivity a series of numerical studies proving the mechanical strength of these components. Its validation, taking into account the feed-back from previous studies, leads us to rely on the results. ASCOUF has afterwards been extended to solve the problems of lack of thickness of pipes of the secondary loop. (authors)

  12. Global sensitivity analysis of thermo-mechanical models in numerical weld modelling; Analyse de sensibilite globale de modeles thermomecaniques de simulation numerique du soudage

    Energy Technology Data Exchange (ETDEWEB)

    Petelet, M

    2007-10-15

    Current approach of most welding modellers is to content themselves with available material data, and to chose a mechanical model that seems to be appropriate. Among inputs, those controlling the material properties are one of the key problems of welding simulation: material data are never characterized over a sufficiently wide temperature range {exclamation_point} This way to proceed neglect the influence of the uncertainty of input data on the result given by the computer code. In this case, how to assess the credibility of prediction? This thesis represents a step in the direction of implementing an innovative approach in welding simulation in order to bring answers to this question, with an illustration on some concretes welding cases. The global sensitivity analysis is chosen to determine which material properties are the most sensitive in a numerical welding simulation and in which range of temperature. Using this methodology require some developments to sample and explore the input space covering welding of different steel materials. Finally, input data have been divided in two groups according to their influence on the output of the model (residual stress or distortion). In this work, complete methodology of the global sensitivity analysis has been successfully applied to welding simulation and lead to reduce the input space to the only important variables. Sensitivity analysis has provided answers to what can be considered as one of the probable frequently asked questions regarding welding simulation: for a given material which properties must be measured with a good accuracy and which ones can be simply extrapolated or taken from a similar material? (author)

  13. Numerical study of the flow in a ball bearing cross-section; Etude numerique de l`ecoulement dans une coupe transversale de roulements a billes

    Energy Technology Data Exchange (ETDEWEB)

    Combes, J.F. [Electricite de France (EDF), 92 - Clamart (France). Direction des Etudes et Recherches; Bidot, T. [Simulog, (France)

    1997-01-01

    In the Ariane rocket propulsion system, ball bearings operate under very severe conditions; in order to evaluate heat transfers enabling their cooling, the flow inside the bearings themselves has to be determined. A numerical study has been carried out by Simulog company using the Turbomachinery release of the N3S code developed by Electricite de France. After a brief presentation of the fluid dynamics N3S code and its turbomachinery version, its application to the calculation of the flow within a ball bearing is presented: as it was shown in a preliminary study, the 3D flow can be split into a succession of 2D flows on parallel slices; therefore examples of laminar and turbulent flow calculation on a cross section are given. Comparison of flow structure calculations with experimental and analytical results is discussed

  14. Multi-scale modelling and numerical simulation of electronic kinetic transport; Modelisation et simulation numerique multi-echelle du transport cinetique electronique

    Energy Technology Data Exchange (ETDEWEB)

    Duclous, R

    2009-11-15

    This research thesis which is at the interface between numerical analysis, plasma physics and applied mathematics, deals with the kinetic modelling and numerical simulations of the electron energy transport and deposition in laser-produced plasmas, having in view the processes of fuel assembly to temperature and density conditions necessary to ignite fusion reactions. After a brief review of the processes at play in the collisional kinetic theory of plasmas, with a focus on basic models and methods to implement, couple and validate them, the author focuses on the collective aspect related to the free-streaming electron transport equation in the non-relativistic limit as well as in the relativistic regime. He discusses the numerical development and analysis of the scheme for the Vlasov-Maxwell system, and the selection of a validation procedure and numerical tests. Then, he investigates more specific aspects of the collective transport: the multi-specie transport, submitted to phase-space discontinuities. Dealing with the multi-scale physics of electron transport with collision source terms, he validates the accuracy of a fast Monte Carlo multi-grid solver for the Fokker-Planck-Landau electron-electron collision operator. He reports realistic simulations for the kinetic electron transport in the frame of the shock ignition scheme, the development and validation of a reduced electron transport angular model. He finally explores the relative importance of the processes involving electron-electron collisions at high energy by means a multi-scale reduced model with relativistic Boltzmann terms.

  15. Some robust numerical methods for flow and transport in porous media; Quelques methodes numeriques robustes pour l'ecoulement et le transport en milieu poreux

    Energy Technology Data Exchange (ETDEWEB)

    Sboui, A

    2007-01-15

    The aim of this thesis is to model and develop numerical tools adapted to study underground water flow and the propagation of pollutants in a porous medium. The main motivation of this work is a benchmark from GDR Momas and ANDRA to simulate the 3-D propagation of radionuclides around a deep disposal of nuclear waste. Firstly, we construct a new mixed finite elements method suitable for general hexahedral meshes. Convergence of the method is proved and shown in numerical experiments. Secondly, we present a method of time discretization for the advection equation which allows for the use of different time steps in different sub-domains in order to take into account of strong heterogeneities. Finally a numerical method for the calculation of the transport of contaminants is proposed. The techniques above were implemented in a 3-D code and simulation results are shown on the 3-D far field benchmark from GDR Momas and ANDRA. (author)

  16. Large scale simulation numerical study of transition to turbulence in jets; Etude numerique par simulation des grandes echelles de la transition a la turbulence dans les jets

    Energy Technology Data Exchange (ETDEWEB)

    Urbin, Gerald [Institut National Polytechnique, 38 - Grenoble (France)

    1998-02-02

    This study highlights the potentialities of the numerical technique of large scale simulation in describing and understanding the turbulent flows in a complex geometry. Particularly, it is focussed on flows of free jet, confined jets and multiple jets of high solidity grid. Spatial simulations of the circular zone close to a free jet, of high Reynolds number were performed. In spite of an evident sensitivity to upstream conditions good agreement between our statistical predictions and different experimental measurements was obtained. The multiple coherent vortical structures implied in the transition to turbulence of the jet were found. At the same time, helical or annular axisymmetric vortices were observed. Also, an original vortical arrangement was evidenced, resulting from the alternating inclination and local pairing of these rings. It could been forced through an ad-hoc excitation which modifies subsequently drastically the jet development. When an axisymmetric excitation is imposed after formation of annular structures, pairs of counter-rotative longitudinal vortices occur and generate lateral jets. Their nature and presence in case of a helical excitation are discussed. An efficient method for controlling their number is developed. Then, one is studied the very low frequency periodic phenomenon of backward-facing transition to turbulence which develops in the confined jet and grid multiple jets (a phenomenon generic in numerous flows). It was found to depend not only on the characteristic of the re-circulation (pre-transition) zones but also on the upstream flow (zone of post-transition stagnation, pressure effect). Large scale transversal motions of the fluid have been found beginning from the grid. An interpretation of this phenomenon is suggested 193 refs., 109 figs.

  17. On the numerical simulation of the laser absorption by Eulerian methods; Sur la simulation numerique de l'absorption laser par des methodes Euleriennes

    Energy Technology Data Exchange (ETDEWEB)

    Sentis, R. [CEA Bruyeres-le-Chatel, Dept. de Conception et Simulation des Armes, 91 (France); Golse, F. [CEA Saclay, Dept. de Modelisation des Systemes et Structures, 91 - Gif-sur-Yvette (France); Lafitte, O. [Paris-7 Univ., 75 (France)]|[Ecole Normale Superieure, 75 - Paris (France)

    2001-07-01

    For the simulation of the laser absorption in a plasma hydrodynamic code, one uses generally a ray tracing method. We show here where are the main difficulties related to a numerical solution of the eikonal equation by an alternative method called Eulerian. We indicate also what way are considered to clear up these difficulties. One of the main assets of the Eulerian method is to give a more regular estimation of the energy absorbed in each elementary volume than the ray-tracing method.

  18. Numerical simulation of energy losses in a wind turbine due to icing; Simulation numerique des pertes energetiques d'une eolienne dues au givrage

    Energy Technology Data Exchange (ETDEWEB)

    Dimitrova, M.; Ibrahim, H. [TechnoCentre eolien Gaspesie-les Iles, Gaspe, PQ (Canada); Fortin, G.; Perron, J. [Quebec Univ., Chicoutimi, PQ (Canada); Ilinca, A. [Quebec Univ., Rimouski, PQ (Canada)

    2010-07-01

    This poster reported on a study that reproduced frost conditions measured on wind turbines in Murdochville, Quebec. Frost accumulation was measured on the NACA 63 415 blade profile of a Vesta V80, 1.8 MW wind turbine. The loss of mass was measured and the form of frost deposited was examined along with lift and drag. Several tests were conducted with various frost precipitation. Meteorological data such as wind velocity, wind direction, air temperature, relative humidity, barometric pressure and solar radiation were recorded along with icing events and their duration. The model was used to determine at which point the drag would cause the turbine to stop turning. refs., tabs., figs.

  19. RESOLUTION NUMERIQUE DE L’EQUATION DE FOKKER-PLANCK ET CALCUL DU COEFFICIENT DE VISCOSITE ELECTRONIQUE D’UN PLASMA COLLISIONNEL TOTALEMENT IONISE

    Directory of Open Access Journals (Sweden)

    A BENDIB

    2001-12-01

    Full Text Available L’équation de Fokker-Planck, qui décrit les électrons d’un plasma complètement ionisé et non magnétisé, a été résolue numériquement. Les collisions électron-ion et électron-électron ont été prises en considération. La fonction de distribution électronique, développée sur la base des polynômes de Legendre, a été calculée jusqu’à la seconde anisotropie. La première anisotropie a été calculée en réduisant le problème à une équation différentielle du quatrième ordre qui peut être résolue numériquement avec les méthodes numériques standards. Les coefficients de transport induits par cette première anisotropie ont été déduits. Ils correspondent exactement à ceux établis dans la littérature par des méthodes numériques différentes, nettement plus complexes. La seconde anisotropie a aussi été calculée en réduisant le problème à une équation différentielle du second ordre en utilisant la méthode itérative. Des résultats très précis sont obtenus à partir de la cinquième itération. La viscosité électronique a été déduite et un ajustement numérique très précis de ce coefficient de transport en fonction du numéro atomique a aussi été proposé.

  20. The IS Services Agency of Wittenheim sets the pace in numerical radiography; L'agence IS Services de Wittenheim a la pointe de la radiographie numerique

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2006-03-15

    Small by its size with only 5 workers, the IS Services Agency of Wittenheim (Alsace) is however ultra specialized in nondestructive testing, and particularly with the new technology of the numerical radiography. (O.M.)

  1. Modelisation numerique des phenomenes physiques du soudage par friction-malaxage et comportement en fatigue de joints soudes en aluminium 7075-T6

    Science.gov (United States)

    Gemme, Frederic

    The aim of the present research project is to increase the amount of fundamental knowledge regarding the process by getting a better understanding of the physical phenomena involved in friction stir welding (FSW). Such knowledge is required to improve the process in the context of industrial applications. In order to do so, the first part of the project is dedicated to a theoretical study of the process, while the microstructure and the mechanical properties of welded joints obtained in different welding conditions are measured and analyzed in the second part. The combination of the tool rotating and translating movements induces plastic deformation and heat generation of the welded material. The material thermomechanical history is responsible for metallurgical phenomena occurring during FSW such as recrystallization and precipitate dissolution and coarsening. Process modelling is used to reproduce this thermomechanical history in order to predict the influence of welding on the material microstructure. It is helpful to study heat generation and heat conduction mechanisms and to understand how joint properties are related to them. In the current work, a finite element numerical model based on solid mechanics has been developed to compute the thermomechanical history of the welded material. The computation results were compared to reference experimental data in order to validate the model and to calibrate unknown physical parameters. The model was used to study the effect of the friction coefficient on the thermomechanical history. Results showed that contact conditions at the workpiece/tool interface have a strong effect on relative amounts of heat generated by friction and by plastic deformation. The comparison with the experimental torque applied by the tool for different rotational speeds has shown that the friction coefficient decreases when the rotational speed increases. Consequently, heat generation is far more important near the material/tool interface and the material deformation is shallower, increasing the lack of penetration probability. The variation of thermomechanical conditions with regards to the rotational speed is responsible for the variation of the nugget shape, as recrystallization conditions are not reached in the same volume of material. The second part of the research project was dedicated to a characterization of the welded joints microstructure and mechanical properties. Sound joints were obtained by using a manufacturing procedure involving process parameters optimization and quality control of the joint integrity. Five different combinations of rotational and advancing speeds were studied. Microstructure observations have shown that the rotational speed has an effect on recrystallization conditions because of the variation of the contact conditions at the material/tool interface. On the other hand, the advancing speed has a strong effect on the precipitation state in the heat affected zone (HAZ). The heat input increases when the advancing speed decreases. The material softening in the HAZ is then more pronounced. Mechanical testing of the welded joints showed that the fatigue resistance increases when the rotational speed increases and the advancing speed decreases. The fatigue resistance of FSW joints mainly depends on the ratio of the advancing speed on the rotational speed, called the welding pitch k. When the welding pitch is high (k ≥ 0,66 mm/rev), the fatigue resistance depends on crack initiation at the root of circular grooves left by the tool on the weld surface. The size of these grooves is directly related to the welding pitch. When the welding pitch is low (k ≤ 0,2 mm/rev), the heat input is high and the fatigue resistance is limited by the HAZ softening. The fatigue resistance is optimized when k stands in the 0,25-0,30 mm/rev range. Outside that range, the presence of small lateral lips is critical. The results of the characterization part of the project showed that the effects of the applied vertical force on the formation of lateral lips should be submitted to further investigations. The elimination of the lateral lip, which could be achieved with a more precise adjustment of the vertical force, could lead to an improved fatigue resistance. The elimination of lateral lips, but also the circular grooves left by the tool, may be obtained by developing an appropriate surfacing technique and could lead to an improved fatigue resistance without reducing the advancing speed. (Abstract shortened by UMI.)

  2. Micromechanical simulation of Uranium dioxide polycrystalline aggregate behaviour under irradiation; Modele numerique micro-mecanique d'agregat polycristallin pour le comportement des combustibles oxydes

    Energy Technology Data Exchange (ETDEWEB)

    Pacull, J.

    2011-02-15

    In pressurized water nuclear power reactor (PWR), the fuel rod is made of dioxide of uranium (UO{sub 2}) pellet stacked in a metallic cladding. A multi scale and multi-physic approaches are needed for the simulation of fuel behavior under irradiation. The main phenomena to take into account are thermomechanical behavior of the fuel rod and chemical-physic behavior of the fission products. These last years one of the scientific issue to improve the simulation is to take into account the multi-physic coupling problem at the microscopic scale. The objective of this ph-D study is to contribute to this multi-scale approach. The present work concerns the micro-mechanical behavior of a polycrystalline aggregate of UO{sub 2}. Mean field and full field approaches are considered. For the former and the later a self consistent homogenization technique and a periodic Finite Element model base on the 3D Voronoi pattern are respectively used. Fuel visco-plasticity is introduced in the model at the scale of a single grain by taking into account specific dislocation slip systems of UO{sub 2}. A cohesive zone model has also been developed and implemented to simulate grain boundary sliding and intergranular crack opening. The effective homogenous behaviour of a Representative Volume Element (RVE) is fitted with experimental data coming from mechanical tests on a single pellet. Local behavior is also analyzed in order to evaluate the model capacity to assess micro-mechanical state. In particular, intra and inter granular stress gradient are discussed. A first validation of the local behavior assessment is proposed through the simulation of intergranular crack opening measured in a compressive creep test of a single fuel pellet. Concerning the impact of the microstructure on the fuel behavior under irradiation, a RVE simulation with a representative transient loading of a fuel rod during a power ramp test is achieved. The impact of local stress and strain heterogeneities on the multi-physic simulation is discussed. (author)

  3. Derivation of the low Mach number diphasic system. Numerical simulation in mono-dimensional geometry; Derivation du systeme diphasique bas Mach. Simulation numerique en geometrie monodimensionnelle

    Energy Technology Data Exchange (ETDEWEB)

    Dellacherie, St

    2004-07-01

    This work deals with the derivation of a diphasic low Mach number model obtained through a Mach number asymptotic expansion applied to the compressible diphasic Navier Stokes system, expansion which filters out the acoustic waves. This approach is inspired from the work of Andrew Majda giving the equations of low Mach number combustion for thin flame and for perfect gases. When the equations of state verify some thermodynamic hypothesis, we show that the low Mach number diphasic system predicts in a good way the dilatation or the compression of a bubble and has equilibrium convergence properties. Then, we propose an entropic and convergent Lagrangian scheme in mono-dimensional geometry when the fluids are perfect gases and we propose a first approach in Eulerian variables where the interface between the two fluids is captured with a level set technique. (author)

  4. Thermophysical characterization tools and numerical models for high temperature thermo-structural composite materials; Outils de caracterisation thermophysique et modeles numeriques pour les composites thermostructuraux a haute temperature

    Energy Technology Data Exchange (ETDEWEB)

    Lorrette, Ch

    2007-04-15

    This work is an original contribution to the study of the thermo-structural composite materials thermal behaviour. It aims to develop a methodology with a new experimental device for thermal characterization adapted to this type of material and to model the heat transfer by conduction within these heterogeneous media. The first part deals with prediction of the thermal effective conductivity of stratified composite materials in the three space directions. For that, a multi scale model using a rigorous morphology analysis of the structure and the elementary properties is proposed and implemented. The second part deals with the thermal characterization at high temperature. It shows how to estimate simultaneously the thermal effusiveness and the thermal conductivity. The present method is based on the observation of the heating from a plane sample submitted to a continuous excitation generated by Joule Effect. Heat transfer is modelled with the quadrupole formalism, temperature is here measured on two sides of the sample. The development of both resistive probes for excitation and linear probes for temperature measurements enables the thermal properties measured up to 1000 C. Finally, some experimental and numerical application examples lead to review the obtained results. (author)

  5. Happiness by Association: Breadth of Free Association Influences Affective States

    Science.gov (United States)

    Brunye, Tad T.; Gagnon, Stephanie A.; Paczynski, Martin; Shenhav, Amitai; Mahoney, Caroline R.; Taylor, Holly A.

    2013-01-01

    Several studies have demonstrated that affective states influence the number of associations formed between remotely related concepts. Someone in a neutral or negative affective state might draw the association between "cold" and "hot", whereas someone in a positive affective state might spontaneously form the more distant association between…

  6. Morphological bidirectional associative memories.

    Science.gov (United States)

    Ritter, G X.; Diaz-de-Leon, J L.; Sussner, P

    1999-07-01

    The theory of artificial neural networks has been successfully applied to a wide variety of pattern recognition problems. In this theory, the first step in computing the next state of a neuron or in performing the next layer neural network computation involves the linear operation of multiplying neural values by their synaptic strengths and adding the results. Thresholding usually follows the linear operation in order to provide for nonlinearity of the network. In this paper we discuss a novel class of artificial neural networks, called morphological neural networks, in which the operations of multiplication and addition are replaced by addition and maximum (or minimum), respectively. By taking the maximum (or minimum) of sums instead of the sum of products, morphological network computation is nonlinear before thresholding. As a consequence, the properties of morphological neural networks are drastically different from those of traditional neural network models. The main emphasis of the research presented here is on morphological bidirectional associative memories (MBAMs). In particular, we establish a mathematical theory for MBAMs and provide conditions that guarantee perfect bidirectional recall for corrupted patterns. Some examples that illustrate performance differences between the morphological model and the traditional semilinear model are also given.

  7. Stimulus Recognition and Associative Coding

    Science.gov (United States)

    Runquist, Willard N.; Evans, Annabel

    1972-01-01

    Purpose of this experiment was to investigate the relationship between stimulus recognition and various learning conditions which were designed to affect both stimulus encoding and associative learning in a paired-associate task. (Authors)

  8. Combinatorial Approach of Associative Classification

    OpenAIRE

    P. R. Pal; R.C. Jain

    2010-01-01

    Association rule mining and classification are two important techniques of data mining in knowledge discovery process. Integration of these two has produced class association rule mining or associative classification techniques, which in many cases have shown better classification accuracy than conventional classifiers. Motivated by this study we have explored and applied the combinatorial mathematics in class association rule mining in this paper. Our algorithm is based on producing co...

  9. On the Associativity of Gluing

    CERN Document Server

    Qin, Lizhen

    2011-01-01

    This paper studies the associativity of gluing of trajectories in Morse theory. We show that the associativity of gluing follows from of the existence of compatible manifold with face structures on the compactified moduli spaces. Using our previous work, we obtain the associativity of gluing in certain cases. In particular, associativity holds when the ambient manifold is compact and the vector field is Morse-Smale.

  10. Associative Hierarchical Random Fields.

    Science.gov (United States)

    Ladický, L'ubor; Russell, Chris; Kohli, Pushmeet; Torr, Philip H S

    2014-06-01

    This paper makes two contributions: the first is the proposal of a new model-The associative hierarchical random field (AHRF), and a novel algorithm for its optimization; the second is the application of this model to the problem of semantic segmentation. Most methods for semantic segmentation are formulated as a labeling problem for variables that might correspond to either pixels or segments such as super-pixels. It is well known that the generation of super pixel segmentations is not unique. This has motivated many researchers to use multiple super pixel segmentations for problems such as semantic segmentation or single view reconstruction. These super-pixels have not yet been combined in a principled manner, this is a difficult problem, as they may overlap, or be nested in such a way that the segmentations form a segmentation tree. Our new hierarchical random field model allows information from all of the multiple segmentations to contribute to a global energy. MAP inference in this model can be performed efficiently using powerful graph cut based move making algorithms. Our framework generalizes much of the previous work based on pixels or segments, and the resulting labelings can be viewed both as a detailed segmentation at the pixel level, or at the other extreme, as a segment selector that pieces together a solution like a jigsaw, selecting the best segments from different segmentations as pieces. We evaluate its performance on some of the most challenging data sets for object class segmentation, and show that this ability to perform inference using multiple overlapping segmentations leads to state-of-the-art results.

  11. The Association's awards and medals

    Science.gov (United States)

    Marriott, R. A.

    2000-02-01

    The Association's first award was inaugurated and funded by Walter Goodacre in 1929. Since then, four other awards have been introduced to honour the names of prominent figures in the Association, and to acknowledge those whose work and achievements have benefited the Association or astronomy in general.

  12. Performance assessment of housing associations

    NARCIS (Netherlands)

    Van Overmeeren, A.J.; Gruis, V.H.; Haffner, M.E.A.

    2009-01-01

    This article analyzes the function, design, and effects of a method to assess the performance of housing associations in the Netherlands. First, the roles of performance assessment are discussed from three perspectives: the association as an agent for the central government; the association as a fac

  13. Submanifolds Weakly Associated with Graphs

    Indian Academy of Sciences (India)

    A Carriazo; L M Fernández; A Rodríguez-Hidalgo

    2009-06-01

    We establish an interesting link between differential geometry and graph theory by defining submanifolds weakly associated with graphs. We prove that, in a local sense, every submanifold satisfies such an association, and other general results. Finally, we study submanifolds associated with graphs either in low dimensions or belonging to some special families.

  14. Reseaux Neuronaux Optiques

    Science.gov (United States)

    Bergeron, Alain

    Cette recherche vise a la mise en oeuvre optique de reseaux neuronaux. Deux architectures differentes sont proposees. La premiere est la memoire associative permettant d'associer a un objet quelconque une sortie arbitraire tout en preservant l'information sur sa position. La seconde architecture, le classificateur neuronal pour le controle robotique, permet l'identification d'une entree et son classement selon differentes categories. La sortie est compatible avec les systemes numeriques standard. Pour realiser ces architectures, une approche modulaire est privilegiee. Le correlateur constitue le module de base des realisations. Differents modules sont de plus introduits pour realiser convenablement les operations neuronales. Le premier de ces modules est le seuil optoelectronique permettant de realiser une fonction non lineaire, element essentiel des reseaux neuronaux. Le second module a etre introduit est l'encodeur optonumerique, utile au classement des objets. Le probleme de l'enregistrement de la memoire est aborde a l'aide du codage iteratif global.

  15. Use of the GATE Monte Carlo package for dosimetry applications

    Energy Technology Data Exchange (ETDEWEB)

    Visvikis, D. [INSERM U650, LaTIM, University Hospital Medical School, F 29609 Brest (France)]. E-mail: Visvikis.Dimitris@univ-brest.fr; Bardies, M. [INSERM U601, CHU Nantes, F 44093 Nantes (France); Chiavassa, S. [INSERM U601, CHU Nantes, F 44093 Nantes (France); Danford, C. [Department of Medical Physics, MSKCC, New York (United States); Kirov, A. [Department of Medical Physics, MSKCC, New York (United States); Lamare, F. [INSERM U650, LaTIM, University Hospital Medical School, F 29609 Brest (France); Maigne, L. [Departement de Curietherapie-Radiotherapie, Centre Jean Perrin, F 63000 Clemont-Ferrand (France); Staelens, S. [UGent-ELIS, St-Pietersnieuwstraat, 41, B 9000 Gent (Belgium); Taschereau, R. [CRUMP Institute for Molecular Imaging, UCLA, Los Angeles (United States)

    2006-12-20

    One of the roles for Monte Carlo (MC) simulation studies is in the area of dosimetry. A number of different codes dedicated to dosimetry applications are available and widely used today, such as MCNP, EGSnrc and PTRAN. However, such codes do not easily facilitate the description of complicated 3D sources or emission tomography systems and associated data flow, which may be useful in different dosimetry application domains. Such problems can be overcome by the use of specific MC codes such as GATE (GEANT4 Application to Tomographic Emission), which is based on Geant4 libraries, providing a scripting interface with a number of advantages for the simulation of SPECT and PET systems. Despite this potential, its major disadvantage is in terms of efficiency involving long execution times for applications such as dosimetry. The strong points and disadvantages of GATE in comparison to other dosimetry specific codes are discussed and illustrated in terms of accuracy, efficiency and flexibility. A number of features, such as the use of voxelised and moving sources, as well as developments such as advanced visualization tools and the development of dose estimation maps allowing GATE to be used for dosimetry applications are presented. In addition, different examples from dosimetry applications with GATE are given. Finally, future directions with respect to the use of GATE for dosimetry applications are outlined.

  16. The optimal encodings for biased association in linear associative memories.

    Science.gov (United States)

    Leung, Yee; Dong, Tian Xin; Xu, Zong Ben

    1998-07-01

    In this paper, optimal encoding schemes for linear associative memories are derived for biased association under both the white-noise and colored-noise situations. Analysis and simulation results all show that the biased encodings thus derived are optimal and superior to existing models in their performance. Together with the Wee-Kohonen unbiased encoding, the study settles the optimality issue of linear associative memories and enhances their practicalities.

  17. Lexical Creativity from Word Associations

    OpenAIRE

    Gross, Oskar; Toivonen, Hannu; Toivanen, Jukka; Valitutti, Alessandro

    2012-01-01

    A fluent ability to associate tasks, concepts, ideas, knowledge and experiences in a relevant way is often considered an important factor of creativity, especially in problem solving. We are interested in providing computational support for discovering such creative associations. In this paper we design minimally supervised methods that can perform well in the remote associates test (RAT), a well-known psychometric measure of creativity. We show that with a large corpus of text and some relat...

  18. Associative learning in biochemical networks

    OpenAIRE

    Ghandi, Nikhil; Ashkenasy, Gonen; Tannenbaum, Emmanuel

    2007-01-01

    We develop a simple, chemostat-based model illustrating how a process analogous to associative learning can occur in a biochemical network. Associative learning is a form of learning whereby a system "learns" to associate two stimuli with one another. In our model, two types of replicating molecules, denoted A and B, are present in some initial concentration in the chemostat. Molecules A and B are stimulated to replicate by some growth factors, denoted GA and GB, respectively. It is also assu...

  19. African Diaspora Associations in Denmark

    DEFF Research Database (Denmark)

    Vammen, Ida Marie; Trans, Lars Ove

    2011-01-01

    Since the early 1990s, an increasing number of African migrants have come to Denmark, where they have formed a large number of migrant associations. This chapter presents selected findings from a comprehensive survey of African diaspora associations in Denmark and focuses specifically on their tr......Since the early 1990s, an increasing number of African migrants have come to Denmark, where they have formed a large number of migrant associations. This chapter presents selected findings from a comprehensive survey of African diaspora associations in Denmark and focuses specifically...

  20. Associative processes in immediate recency

    National Research Council Canada - National Science Library

    Howard, Marc W; Venkatadass, Vijay; Norman, Kenneth A; Kahana, Michael J

    2007-01-01

    .... If associative processes contribute to immediate recency, as predicted by the temporal context account, the neighbors of the initial presentation of the repeated item should show enhanced recall...

  1. Global Employer and Business Associations

    DEFF Research Database (Denmark)

    Ronit, Karsten

    2016-01-01

    leadership functions, while global associations meet a variety of demands from their diverse constituencies and assist members in building capacities. These relations take many different forms, but they are important in all global associations, and the analysis of these patterns of collective action have...... implications for our understanding of global politics where new approaches are needed to analyse the institutionalisation of business interests....

  2. Association mapping in tetraploid potato

    NARCIS (Netherlands)

    hoop, D' B.B.

    2009-01-01

    The results of a four year project within the Centre for BioSystems Genomics (www.cbsg.nl), entitled “Association mapping and family genotyping in potato” are described in this thesis. This project was intended to investigate whether a recently emerged methodology, association mapping, could provide

  3. Turtle-associated human salmonellosis.

    NARCIS (Netherlands)

    Stam, F.; Romkens, TE; Hekker, TA; Smulders, Y.M.

    2003-01-01

    A patient who bred exotic turtles as a hobby presented with 2 episodes of severe diarrhea, the second of which was proven to be caused by turtle-associated salmonellosis that was contracted during treatment with a proton-pump inhibitor. The literature about reptile-associated salmonellosis is briefl

  4. The Tourette Syndrome Association, Inc.

    Science.gov (United States)

    Levi, Sue L.

    1991-01-01

    The article briefly describes the Tourette Syndrome Association, an association which works to advance public understanding, treatment, and the correct diagnosis of this neurological impairment, which can involve "bizarre" behavioral symptoms as well as learning, attention, and impulse control problems. (DB)

  5. Associativity relations in quantum cohomology

    OpenAIRE

    Kresch, Andrew

    1997-01-01

    We describe interdependencies among the quantum cohomology associativity relations. We strengthen the first reconstruction theorem of Kontsevich and Manin by identifying a subcollection of the associativity relations which implies the full system of WDVV equations. This provides a tool for identifying non-geometric solutions to WDVV.

  6. Association mapping in tetraploid potato

    NARCIS (Netherlands)

    hoop, D' B.B.

    2009-01-01

    The results of a four year project within the Centre for BioSystems Genomics (www.cbsg.nl), entitled “Association mapping and family genotyping in potato” are described in this thesis. This project was intended to investigate whether a recently emerged methodology, association mapping, could provide

  7. The Associative Nature of Creativity

    DEFF Research Database (Denmark)

    Friis-Olivarius, Morten

    The overarching objective of this doctoral dissertation is to advance our understanding of the role of associations in creative thought and creativity training. While research in associative abilities and creativity has a long history and lies at the heart of many prevailing theories of creativity...

  8. Weak associativity and deformation quantization

    Directory of Open Access Journals (Sweden)

    V.G. Kupriyanov

    2016-09-01

    Full Text Available Non-commutativity and non-associativity are quite natural in string theory. For open strings it appears due to the presence of non-vanishing background two-form in the world volume of Dirichlet brane, while in closed string theory the flux compactifications with non-vanishing three-form also lead to non-geometric backgrounds. In this paper, working in the framework of deformation quantization, we study the violation of associativity imposing the condition that the associator of three elements should vanish whenever each two of them are equal. The corresponding star products are called alternative and satisfy important for physical applications properties like the Moufang identities, alternative identities, Artin's theorem, etc. The condition of alternativity is invariant under the gauge transformations, just like it happens in the associative case. The price to pay is the restriction on the non-associative algebra which can be represented by the alternative star product, it should satisfy the Malcev identity. The example of nontrivial Malcev algebra is the algebra of imaginary octonions. For this case we construct an explicit expression of the non-associative and alternative star product. We also discuss the quantization of Malcev–Poisson algebras of general form, study its properties and provide the lower order expression for the alternative star product. To conclude we define the integration on the algebra of the alternative star products and show that the integrated associator vanishes.

  9. Associative concept learning in animals.

    Science.gov (United States)

    Zentall, Thomas R; Wasserman, Edward A; Urcuioli, Peter J

    2014-01-01

    Nonhuman animals show evidence for three types of concept learning: perceptual or similarity-based in which objects/stimuli are categorized based on physical similarity; relational in which one object/stimulus is categorized relative to another (e.g., same/different); and associative in which arbitrary stimuli become interchangeable with one another by virtue of a common association with another stimulus, outcome, or response. In this article, we focus on various methods for establishing associative concepts in nonhuman animals and evaluate data documenting the development of associative classes of stimuli. We also examine the nature of the common within-class representation of samples that have been associated with the same reinforced comparison response (i.e., many-to-one matching) by describing manipulations for distinguishing possible representations. Associative concepts provide one foundation for human language such that spoken and written words and the objects they represent become members of a class of interchangeable stimuli. The mechanisms of associative concept learning and the behavioral flexibility it allows, however, are also evident in the adaptive behaviors of animals lacking language.

  10. Color-shape associations revealed with implicit association tests.

    Directory of Open Access Journals (Sweden)

    Na Chen

    Full Text Available Kandinsky proposed a correspondence theory that suggests associations between specific colors and shapes (i.e., circle-blue, square-red, triangle-yellow. Makin and Wuerger tested the theory using the Implicit Association Test (IAT and did not find clear evidence for Kandinsky's color-shape associations among British participants. In the present study, we first replicated the previous study among Japanese participants and found similar results to those of Makin and Wuerger, showing little support for Kandinsky's theory. In the subsequent experiment, we tested another set of color-shape associations that had been revealed by using an explicit matching method (circle-red, square-blue, triangle-yellow in Japanese participants. The IAT tests showed that response times were significantly faster when circle-red, square-blue, and triangle-yellow combinations were mapped onto the same response key, rather than different key combinations, indicating that these color-shape combinations were encoded. These results provide the first empirical evidence that color-shape associations can be measured by indirect behavioral methods, and in particular, Japanese people's color-shape associations (circle-red, square-blue, triangle-yellow can be observed by both direct and indirect experimental methods.

  11. Color-shape associations revealed with implicit association tests.

    Science.gov (United States)

    Chen, Na; Tanaka, Kanji; Watanabe, Katsumi

    2015-01-01

    Kandinsky proposed a correspondence theory that suggests associations between specific colors and shapes (i.e., circle-blue, square-red, triangle-yellow). Makin and Wuerger tested the theory using the Implicit Association Test (IAT) and did not find clear evidence for Kandinsky's color-shape associations among British participants. In the present study, we first replicated the previous study among Japanese participants and found similar results to those of Makin and Wuerger, showing little support for Kandinsky's theory. In the subsequent experiment, we tested another set of color-shape associations that had been revealed by using an explicit matching method (circle-red, square-blue, triangle-yellow) in Japanese participants. The IAT tests showed that response times were significantly faster when circle-red, square-blue, and triangle-yellow combinations were mapped onto the same response key, rather than different key combinations, indicating that these color-shape combinations were encoded. These results provide the first empirical evidence that color-shape associations can be measured by indirect behavioral methods, and in particular, Japanese people's color-shape associations (circle-red, square-blue, triangle-yellow) can be observed by both direct and indirect experimental methods.

  12. Marijuana effects on associative processes.

    Science.gov (United States)

    Block, R I; Wittenborn, J R

    1985-01-01

    Acute marijuana effects on associative processes involved in long-term memory retrieval were studied. Results were partially consistent with expectations based on previous subjective reports that marijuana promotes more uncommon associations. Marijuana altered responses when people gave as many examples of a specified category (e.g., CLOTHING) as they could for 2 min, and when they gave an example of a specified category beginning with a specified letter (e.g., WEAPON - G). Reaction time in the latter task and in prior studies was not altered in the expected manner, a finding problematic for some theoretic interpretations of marijuana's effects on associative processes.

  13. Sarcoidosis associated with neuromyelitis optica.

    Science.gov (United States)

    Sawaya, Raja; Radwan, Wael

    2013-08-01

    Neuromyelitis optica (NMO) is an autoimmune disorder diagnosed by an elongated spinal cord lesion associated with unilateral or bilateral optic neuritis and anti-aquaporin 4 (AQP4) antibodies in the serum. It is triggered by or associated with several autoimmune diseases, but not with sarcoidosis. It responds to immunomodulators better than to steroid treatment. Sarcoidosis is an autoimmune disorder which manifests as non-caseating granulomas, usually in the lung parenchyma, but also in other tissues, including the brain. The involvement of the central nervous system in neurosarcoidosis differs considerably from that in neuromyelitis optica and the association of these two diseases concurrently in the same patient is unusual.

  14. Associative processes in intuitive judgment.

    Science.gov (United States)

    Morewedge, Carey K; Kahneman, Daniel

    2010-10-01

    Dual-system models of reasoning attribute errors of judgment to two failures: the automatic operations of a 'System 1' generate a faulty intuition, which the controlled operations of a 'System 2' fail to detect and correct. We identify System 1 with the automatic operations of associative memory and draw on research in the priming paradigm to describe how it operates. We explain how three features of associative memory--associative coherence, attribute substitution and processing fluency--give rise to major biases of intuitive judgment. Our article highlights both the ability of System 1 to create complex and skilled judgments and the role of the system as a source of judgment errors.

  15. Microtubules, Tubulins and Associated Proteins.

    Science.gov (United States)

    Raxworthy, Michael J.

    1988-01-01

    Reviews much of what is known about microtubules, which are biopolymers consisting predominantly of subunits of the globular protein, tubulin. Describes the functions of microtubules, their structure and assembly, microtube associated proteins, and microtubule-disrupting agents. (TW)

  16. China-ASEAN Association Launched

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    <正>The establishment of the China-ASEAN Association was declared on August 3, 2004. Gu Xiulian, vice chairperson of the Standing Committee of the National People’s Congress, took up the presidency.

  17. American Association for Geriatric Psychiatry

    Science.gov (United States)

    ... in your area. Read more » AAGP Journal Official Journal of the American Association for Geriatric Psychiatry. Read more ... RESEARCHERS GMHF Scholars Since my program is so small and there is not much interest among my ...

  18. Stereotype Associations and Emotion Recognition

    NARCIS (Netherlands)

    Bijlstra, Gijsbert; Holland, Rob W.; Dotsch, Ron; Hugenberg, Kurt; Wigboldus, Daniel H. J.

    We investigated whether stereotype associations between specific emotional expressions and social categories underlie stereotypic emotion recognition biases. Across two studies, we replicated previously documented stereotype biases in emotion recognition using both dynamic (Study 1) and static

  19. Business Associations and Private Ordering

    NARCIS (Netherlands)

    Prüfer, J.

    2012-01-01

    Abstract: We study the capacity of business associations - private, formal, noncommercial organizations designed to promote the common business interests of their members - to support contract enforcement and collective action. Inspired by recent empirical literature, our theoretical framework conne

  20. American Association Of State Climatologists

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Records documenting the business, membership, and meetings of the American Association of State Climatologists, from 1976-92. Material donated in 2008 by the estate...

  1. Children's Hemiplegia and Stroke Association

    Science.gov (United States)

    ... here for you. Read More > Helping Kids With Hemiplegia – Orthotic Grants We’re helping kids walk! Kids ... alone. Join us! Learn more > Helping Kids With Hemiplegia The Children’s Hemiplegia and Stroke Association (CHASA) is ...

  2. HPV-Associated Cancers Statistics

    Science.gov (United States)

    ... Breast Cervical Colorectal (Colon) Liver Lung Ovarian Prostate Skin Uterine Vaginal and Vulvar Cancer Home HPV-Associated Cancer Statistics Language: English Español (Spanish) Recommend on Facebook Tweet ...

  3. HPV-associated oral warts.

    Science.gov (United States)

    Feller, L; Khammissa, R A G; Wood, N H; Marnewick, J C; Meyerov, R; Lemmer, J

    2011-03-01

    Human papillomavirus (HPV) is strictly epitheliotropic, infecting stratified squamous cutaneous and mucosal epithelial cells. Oral HPV infection may be subclinical or putatively associated with benign or malignant oral neoplasms. The benign HPV-associated oral lesions, focal epithelial hyperplasia (Heck disease), oral squamous cell papilloma, oral verruca vulgaris (common wart) and oral condyloma acuminatum, are collectively referred to as oral warts. Oral warts are usually asymptomatic, may be persistent or uncommonly, may regress spontaneously. HPV-associated oral warts have a prevalence of 0.5% in the general population, occur in up to 5% of HIV-seropositive subjects, and in up to 23% of HIV-seropositive subjects on highly active antiretroviral therapy. This paper is a clinico-pathological review of HPV-associated oral warts.

  4. A State Nurses' Association Perspective.

    Science.gov (United States)

    Boyer, Cheryl M.

    1983-01-01

    Discusses the accreditation and evolution of continuing education programs developed by state nurses' associations and other nursing organizations and the value of the accreditation. Also relates current accreditation system to the future of professional continuing education. (JOW)

  5. Business Associations and Private Ordering

    NARCIS (Netherlands)

    Prüfer, J.

    2012-01-01

    Abstract: We study the capacity of business associations - private, formal, noncommercial organizations designed to promote the common business interests of their members - to support contract enforcement and collective action. Inspired by recent empirical literature, our theoretical framework conne

  6. Association of prediabetes-associated single nucleotide polymorphisms with microalbuminuria

    Science.gov (United States)

    Choi, Jong Wook; Moon, Shinje; Jang, Eun Jung; Lee, Chang Hwa; Park, Joon-Sung

    2017-01-01

    Increased glycemic exposure, even below the diagnostic criteria for diabetes mellitus, is crucial in the pathogenesis of diabetic microvascular complications represented by microalbuminuria. Nonetheless, there is limited evidence regarding which single nucleotide polymorphisms (SNPs) are associated with prediabetes and whether genetic predisposition to prediabetes is related to microalbuminuria, especially in the general population. Our objective was to answer these questions. We conducted a genomewide association study (GWAS) separately on two population-based cohorts, Ansung and Ansan, in the Korean Genome and Epidemiology Study (KoGES). The initial GWAS was carried out on the Ansung cohort, followed by a replication study on the Ansan cohort. A total of 5682 native Korean participants without a significant medical illness were classified into either control group (n = 3153) or prediabetic group (n = 2529). In the GWAS, we identified two susceptibility loci associated with prediabetes, one at 17p15.3-p15.1 in the GCK gene and another at 7p15.1 in YKT6. When variations in GCK and YKT6 were used as a model of prediabetes, this genetically determined prediabetes increased microalbuminuria. Multiple logistic regression analyses revealed that fasting glucose concentration in plasma and SNP rs2908289 in GCK were associated with microalbuminuria, and adjustment for age, gender, smoking history, systolic blood pressure, waist circumference, and serum triglyceride levels did not attenuate this association. Our results suggest that prediabetes and the associated SNPs may predispose to microalbuminuria before the diagnosis of diabetes mellitus. Further studies are needed to explore the details of the physiological and molecular mechanisms underlying this genetic association. PMID:28158221

  7. Noise-enhanced associative memories

    OpenAIRE

    Karbasi, Amin; Salavati, Amir Hesam; Shokrollahi, Amin; Varshney, Lav R.

    2013-01-01

    Recent advances in associative memory design through structured pattern sets and graph-based inference algorithms have allowed reliable learning and recall of an exponential number of patterns. Although these designs correct external errors in recall, they assume neurons that compute noiselessly, in contrast to the highly variable neurons in hippocampus and olfactory cortex. Here we consider associative memories with noisy internal computations and analytically characterize performance. As lo...

  8. Insomnia: prevalence and associated factors

    OpenAIRE

    Lopes, Cátia; Lopes, Daniela; Ferreira, Sofia; Correia, Teresa; Pinto, Isabel C.

    2014-01-01

    Nowadays sleep disorders are very common and affect most of the population, the most common may be insomnia. Insomnia is defined as the difficulty of initiating or maintaining sleep it, may also be reflected in an early wake up and by the presence of a non-restful sleep and it is associated with impairment in social and occupational functioning of the individual. Knowing the prevalence and the associated factors of insomnia. This is a cross-sectional epidemiological study. The pop...

  9. HIV-associated anal cancer

    OpenAIRE

    Newsom-Davis, Thomas; Bower, Mark

    2010-01-01

    HIV-associated anal carcinoma, a non-AIDS-defining cancer, is a human papillomavirus-associated malignancy with a spectrum of preinvasive changes. The standardized incidence ratio for anal cancer in patients with HIV/AIDS is 20-50. Algorithms for anal cancer screening include anal cytology followed by high-resolution anoscopy for those with abnormal findings. Outpatient topical treatments for anal intraepithelial neoplasia include infrared coagulation therapy, trichloroacetic acid, and imiqui...

  10. Migrant Associations, Trade and FDI

    OpenAIRE

    Baghdadi, Leila; Cheptea, Angela

    2010-01-01

    Recent literature sets forth the positive role of migrants in international trade and foreign direct investment. We use a new database on French migrant associations together with data on the stocks of migrants to diffe-rentiate between organized and, respectively, non-organized migrant-based networks. We find that the creation of a new association of migrants is accompanied by important jumps in bilateral trade and investment between the host and origin countries. This effect adds on top of ...

  11. HIV Associated Lupus Like Nephropathy

    OpenAIRE

    2014-01-01

    Background Human immunodeficiency virus type 1 (HIV-1)-seropositive patients are at a high risk for the development of a variety of acute and chronic renal diseases. Most patients with HIVAN are of African descent, presenting late in the course of their HIV-1 infection. The only reliable test to establish or rule out the presence of HIVAN (HIV associated nephropathy) is renal biopsy. The most common lesion associated with HIV is a focal segmental glomeruloscelerosis, but several times, other ...

  12. Disability associated with mental disorders

    OpenAIRE

    2006-01-01

    Background: Disability associated with mental illness is a major contributor to the global burden of disease. The present study looks at some aspects of disability associated with 7 psychiatric disorders: schizophrenia, bipolar affective disorder, anxiety disorders, depression, obsessive–compulsive disorder, dementia, and mental and behavioural disorders due to the use of alcohol. Aims: (i) To evaluate the nature and quantity of disabilities in the study groups; (ii) to compare the degree of ...

  13. Vitiligo associated with esophageal adenocarcinoma

    Directory of Open Access Journals (Sweden)

    Ali Asilian

    2013-01-01

    Full Text Available Vitiligo is a disease that results in depigmented areas in the skin. It may develop at any age but the average age at onset is 20 years. Association of vitiligo and melanoma has been commonly reported, but malignancies other than melanoma have been rarely associated with vitiligo. We report a 73-year-old patient with new onset vitiligo who developed esophageal adenocarcinoma in the following years.

  14. Weak associativity and deformation quantization

    CERN Document Server

    Kupriyanov, V G

    2016-01-01

    Non-commutativity is quite natural in string theory. For open strings it appears due to the presence of non-vanishing background two-form in the world volume of Dirichlet brane, while in closed string theory the flux compactifications with non-vanishing three-form also lead to non-commutativity. Except for some specific cases, like the constant $B$-field in open strings, the string coordinates are not only non-commutative, but also non-associative. It manifests the non-geometric nature of the consistent string vacua. The aim of this paper is to study the mathematical tools necessary to deal with non-associativity in physics. Working in the framework of deformation quantization we admit non-associative star products, but keep the violation of associativity under control. We require that the star associator of three functions should vanish whenever each two of them are iqual. Such a star product is called alternative. This condition imposes the restriction on non-associative algebras, the star commutator should...

  15. Associative processing and paranormal belief.

    Science.gov (United States)

    Gianotti, L R; Mohr, C; Pizzagalli, D; Lehmann, D; Brugger, P

    2001-12-01

    In the present study we introduce a novel task for the quantitative assessment of both originality and speed of individual associations. This 'BAG' (Bridge-the-Associative-Gap) task was used to investigate the relationships between creativity and paranormal belief. Twelve strong 'believers' and 12 strong 'skeptics' in paranormal phenomena were selected from a large student population (n > 350). Subjects were asked to produce single-word associations to word pairs. In 40 trials the two stimulus words were semantically indirectly related and in 40 other trials the words were semantically unrelated. Separately for these two stimulus types, response commonalities and association latencies were calculated. The main finding was that for unrelated stimuli, believers produced associations that were more original (had a lower frequency of occurrence in the group as a whole) than those of the skeptics. For the interpretation of the result we propose a model of association behavior that captures both 'positive' psychological aspects (i.e., verbal creativity) and 'negative' aspects (susceptibility to unfounded inferences), and outline its relevance for psychiatry. This model suggests that believers adopt a looser response criterion than skeptics when confronted with 'semantic noise'. Such a signal detection view of the presence/absence of judgments for loose semantic relations may help to elucidate the commonalities between creative thinking, paranormal belief and delusional ideation.

  16. [Neuroanatomy of Frontal Association Cortex].

    Science.gov (United States)

    Takada, Masahiko

    2016-11-01

    The frontal association cortex is composed of the prefrontal cortex and the motor-related areas except the primary motor cortex (i.e., the so-called higher motor areas), and is well-developed in primates, including humans. The prefrontal cortex receives and integrates large bits of diverse information from the parietal, temporal, and occipital association cortical areas (termed the posterior association cortex), and paralimbic association cortical areas. This information is then transmitted to the primary motor cortex via multiple motor-related areas. Given these facts, it is likely that the prefrontal cortex exerts executive functions for behavioral control. The functional input pathways from the posterior and paralimbic association cortical areas to the prefrontal cortex are classified primarily into six groups. Cognitive signals derived from the prefrontal cortex are conveyed to the rostral motor-related areas to transform them into motor signals, which finally enter the primary motor cortex via the caudal motor-related areas. Furthermore, it has been shown that, similar to the primary motor cortex, areas of the frontal association cortex form individual networks (known as "loop circuits") with the basal ganglia and cerebellum via the thalamus, and hence are extensively involved in the expression and control of behavioral actions.

  17. Dengue-associated kidney disease.

    Science.gov (United States)

    Lizarraga, Karlo J; Nayer, Ali

    2014-01-01

    A mosquito-borne viral illness highly prevalent in the tropics and subtropics, dengue is considered a major global health threat by the World Health Organization. Directory of Open Access Journals (DOAJ), Google Scholar, PubMed (NLM), LISTA (EBSCO) and Web of Science have been searched. An RNA virus from the genus Flavivirus, dengue virus is transmitted by Aedes aegypti,the yellow fever mosquito. Dengue is asymptomatic in as many as one half of infected individuals. Dengue fever is an acute febrile illness accompanied by constitutional symptoms. Dengue hemorrhagic fever and dengue shock syndrome are the severe forms of dengue infection.Dengue infection has been associated with a variety of renal disorders. Acute renal failure is a potential complication of severe dengue infection and is typically associated with hypotension, rhabdomyolysis, or hemolysis. Acute renal failure complicates severe dengue infection in 2-5% of the cases and carries a high mortality rate. Proteinuria has been detected in as high as 74% of patients with severe dengue infection. Hematuria has been reported in up to 12.5% of patients. Various types of glomerulonephritis have been reported during or shortly after dengue infection in humans and mouse models of dengue infection. Mesangial proliferation and immune complex deposition are the dominant histologic features of dengue-associated glomerulonephritis. On a rare occasion, dengue infection is associated with systemic autoimmune disorders involving the kidneys. In the vast majority of cases, dengue infection and associated renal disorders are self-limited.

  18. Forward Association, Backward Association, and the False-Memory Illusion

    Science.gov (United States)

    Brainerd, C. J.; Wright, Ron

    2005-01-01

    In the Deese-Roediger-McDermott false-memory illusion, forward associative strength (FAS) is unrelated to the strength of the illusion; this is puzzling, because high-FAS lists ought to share more semantic features with critical unpresented words than should low-FAS lists. The authors show that this null result is probably a truncated range…

  19. Habitat association of Klebsiella species.

    Science.gov (United States)

    Bagley, S T

    1985-02-01

    The genus Klebsiella is seemingly ubiquitous in terms of its habitat associations. Klebsiella is a common opportunistic pathogen for humans and other animals, as well as being resident or transient flora (particularly in the gastrointestinal tract). Other habitats include sewage, drinking water, soils, surface waters, industrial effluents, and vegetation. Until recently, almost all these Klebsiella have been identified as one species, ie, K. pneumoniae. However, phenotypic and genotypic studies have shown that "K. pneumoniae" actually consists of at least four species, all with distinct characteristics and habitats. General habitat associations of Klebsiella species are as follows: K. pneumoniae--humans, animals, sewage, and polluted waters and soils; K. oxytoca--frequent association with most habitats; K. terrigena--unpolluted surface waters and soils, drinking water, and vegetation; K. planticola--sewage, polluted surface waters, soils, and vegetation; and K. ozaenae/K. rhinoscleromatis--infrequently detected (primarily with humans).

  20. Lynch syndrome-associated neoplasms

    DEFF Research Database (Denmark)

    Shia, Jinru; Holck, Susanne; Depetris, Giovanni;

    2013-01-01

    of interacting developments from the disciplines of clinical oncology, pathology, and molecular genetics, with each development serving to guide or enhance the next. The advancement of our understanding about the pathology of Lynch syndrome associated tumors exemplifies such intimate interplay among disciplines....... Today, accumulative knowledge has enabled surgical pathologists to detect tumors that are likely to be associated with Lynch syndrome, and the pathologist is playing an increasingly more important role in the care of these patients. The pathologist's ability is afforded primarily by information gained...... of such information. This article provides an overview of the development of histopathology and immunohistochemistry in Lynch syndrome-associated tumors, particularly in colorectal and endometrial cancers, and outlines the issues and current status of these specific pathologic aspects in not only the major tumors...

  1. Addison's disease and its associations.

    Science.gov (United States)

    Puttanna, Amar; Cunningham, Alana Rosaleen; Dainty, Philip

    2013-07-26

    Addison's disease is a relatively rare endocrine condition resulting from adrenal insufficiency due to various causes. Weight loss is a common feature; however, patients may be seen by a variety of specialists, even requiring acute admission before the diagnosis is made. Addison's disease is commonly associated with other autoimmune diseases. In some cases such as autoimmune polyendocrine syndromes (APS) types 1 and 2, these associations are more commonly found. We present a case of one such patient who presented to the acute medical team having been referred to the gastrointestinal services in the previous year for persistent vomiting and weight loss. On review of history, the cause of vomiting and weight loss was questioned and combined with subsequent biochemical testing a diagnosis of Addison's disease was made. The patient was also noted to have other associated endocrine and autoimmune conditions.

  2. The Staff Association and you

    CERN Multimedia

    Association du personnel

    2013-01-01

    The Staff Association, your representative with the Management and the Member States The article VII 1.01 of the Staff Rules and Regulations (SR&R) provides that “the relations between the Director-General and the personnel shall be established either on an individual basis or on a collective basis with the Staff Association as intermediary”. This essential role of the Staff representatives, of being the spokesperson of the entire staff of the Organization vis-à-vis the Director-General and the Members States, is achieved through regular participation in the various joint advisory committees defined in the SR&R. The most important are the Standing Concertation Committee and the TREF, tripartite forum where your representatives meet with the Member States delegates, in the presence of the Management, to explain the position of the staff on the various issues concerning employment conditions. The Finance Committee also gives the opportunity to the Staff Association to ...

  3. Bioprospecting plant-associated microbiomes.

    Science.gov (United States)

    Müller, Christina A; Obermeier, Melanie M; Berg, Gabriele

    2016-10-10

    There is growing demand for new bioactive compounds and biologicals for the pharmaceutical, agro- and food industries. Plant-associated microbes present an attractive and promising source to this end, but are nearly unexploited. Therefore, bioprospecting of plant microbiomes is gaining more and more attention. Due to their highly specialized and co-evolved genetic pool, plant microbiomes host a rich secondary metabolism. This article highlights the potential detection and use of secondary metabolites and enzymes derived from plant-associated microorganisms in biotechnology. As an example we summarize the findings from the moss microbiome with special focus on the genus Sphagnum and its biotechnological potential for the discovery of novel microorganisms and bioactive molecules. The selected examples illustrate unique and yet untapped properties of plant-associated microbiomes, which are an immense treasure box for future research.

  4. Pattern Discovery Using Association Rules

    Directory of Open Access Journals (Sweden)

    Ms Kiruthika M,

    2011-12-01

    Full Text Available The explosive growth of Internet has given rise to many websites which maintain large amount of user information. To utilize this information, identifying usage pattern of users is very important. Web usage mining is one of the processes of finding out this usage pattern and has many practical applications. Our paper discusses how association rules can be used to discover patterns in web usage mining. Our discussion starts with preprocessing of the given weblog, followed by clustering them and finding association rules. These rules provide knowledge that helps to improve website design, in advertising, web personalization etc.

  5. Rhombencephalitis associated with Dengue fever.

    Science.gov (United States)

    Verma, Rajesh; Bharti, Kavita; Mehta, Mannan; Bansod, Amrit

    2016-05-01

    Dengue infection is gradually disseminating throughout the world in alarming proportions. It is a arbovirus infection,transmitted by aedes mosquitoes. It is a multi-systemic disorder associated with varied neurological complications. There is increased trend of development of neurological complications in dengue fever. The neurological complications arising due to dengue infection can be categorized into central and neuromuscular complications. The central nervous system disorders reported with dengue fever are encephalopathy,encephalitis and myelitis.Here we report a case of rhombencephalitis associated with dengue fever. The literature does not mention rhombencephalitis occurring with dengue illness.

  6. Asymptotics for Associated Random Variables

    CERN Document Server

    Oliveira, Paulo Eduardo

    2012-01-01

    The book concerns the notion of association in probability and statistics. Association and some other positive dependence notions were introduced in 1966 and 1967 but received little attention from the probabilistic and statistics community. The interest in these dependence notions increased in the last 15 to 20 years, and many asymptotic results were proved and improved. Despite this increased interest, characterizations and results remained essentially scattered in the literature published in different journals. The goal of this book is to bring together the bulk of these results, presenting

  7. WORD ASSOCIATIONS IN VOCABULARY LEARNING

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    With the widespread adoption of new college Englishtextbooks,vocabulary learning seems a more important taskthan ever before for college students.This paper is about aresearch on how to help students learn English words moremeaningfully and enlarge their vocabulary more efficiently.This paper first discusses word meaning,concept,andconcept network,then explores the associative network of wordsand their associations,which corresponds to English lexicalrelations.The lexical network can be realized onto a computer tobenefit students in their learning.

  8. Floating patella associated with lymphoedema

    Science.gov (United States)

    Vun, Shen Hwa; Bayam, Levent; Drampalos, Efstathios; Jesry, Mohammed; Fadel, George

    2015-01-01

    Ipsilateral injury of more than one component of the knee extensor apparatus is rare. It is mostly associated with previous trauma, surgery, immunosuppression therapy and systemic disease. We present the first documented case of a spontaneous bifocal disruption of the knee extensor apparatus (i.e. floating patella) associated with lymphoedema. This case highlights the importance of considering lymphoedema as another risk factor for rupture of the knee extensor apparatus. It also highlights the importance of assessing all components of the knee extensor apparatus in patients presenting with acute knee injuries. PMID:25802253

  9. Pregnancy risks associated with obesity.

    Science.gov (United States)

    Mission, John F; Marshall, Nicole E; Caughey, Aaron B

    2015-06-01

    Obesity has increased dramatically in the United States over the last several decades, with approximately 40% of pregnant women now considered overweight or obese. Obesity has been shown to be associated with numerous poor pregnancy outcomes, including increased rates of preeclampsia, gestational diabetes, fetal macrosomia, stillbirth, postterm pregnancy, and increased rates of cesarean delivery. Many of these complications have been found to increase even further with increasing body mass index in a dose-response fashion. In this review, the association of obesity with maternal, fetal, and pregnancy outcomes is discussed as are the recommendations for caring for the obese gravida.

  10. Hebeloma species associated with Cistus.

    Science.gov (United States)

    Eberhardt, Ursula; Beker, Henry J; Vila, Jordi; Vesterholt, Jan; Llimona, Xavier; Gadjieva, Rena

    2009-01-01

    The genus Hebeloma has a number of species highly specific to Cistus and others that occur with several host genera. This paper discusses the species of Hebeloma that appear to be ectomycorrhizal with Cistus, judging from their occurrence when Cistus is the only available host. The previously unknown species H. plesiocistum spec. nov. is described. We also provide a key to the known Hebeloma associates of Cistus. Molecular analyses based on ITS sequence data further illustrate the distinctness of the newly described species and difficulties in the species delimitation with view to H. erumpens. Specific associations with Cistus may have evolved more than once within the genus Hebeloma.

  11. Cancer-associated lysosomal changes

    DEFF Research Database (Denmark)

    Kallunki, T; Olsen, O D; Jaattela, Marja

    2013-01-01

    Rapidly dividing and invasive cancer cells are strongly dependent on effective lysosomal function. Accordingly, transformation and cancer progression are characterized by dramatic changes in lysosomal volume, composition and cellular distribution. Depending on one's point of view, the cancer-associated......-targeting anti-cancer drugs. In this review we compile our current knowledge on cancer-associated changes in lysosomal composition and discuss the consequences of these alterations to cancer progression and the possibilities they can bring to cancer therapy.Oncogene advance online publication, 9 July 2012; doi...

  12. Factors associated with childhood obesity.

    Science.gov (United States)

    Dietz, W

    1991-01-01

    Childhood obesity is associated with host factors that enhance susceptibility and environmental factors that increase food intake and decrease energy expenditure. Obese children underreport food intake and probably consume more food to maintain their weight at increased levels. Prevalence of obesity is related to family variables, including parental obesity, family size and age, and socioeconomic status. Television viewing is strongly associated with the prevalence of obesity through its impact on food intake and activity. How these environmental variables are behaviorally interrelated to the genesis of obesity is unclear.

  13. New quantitative and multi-modal approach for in-vivo studies of small animals: coupling of the {beta}-microprobe with magnetic techniques and development of voxelized rat and mouse phantoms; Nouvelle approche multimodale et quantitative pour les etudes in vivo chez le petit animal: couplage de la {beta}-MicroProbe aux techniques magnetiques et developpement de fantomes de rat et de souris voxelises

    Energy Technology Data Exchange (ETDEWEB)

    Desbree, A

    2005-09-15

    For the last 15 years, animal models that mimic human disorders have become ubiquitous participants to understand biological mechanisms and human disorders and to evaluate new therapeutic approaches. The necessity to study these models in the course of time has stimulated the development of instruments dedicated to in vivo small animal studies. To further understand physiopathological processes, the current challenge is to couple simultaneously several of these methods. Given this context, the combination of the magnetic and radioactive techniques remains an exciting challenge since it is still limited by strict technical constraints. Therefore we propose to couple the magnetic techniques with the radiosensitive Beta-Microprobe, developed in the IPB group and which shown to be an elegant alternative to PET measurements. In this context, the thesis was dedicated to the study of the coupling feasibility from a physical point of view, by simulation and experimental characterizations. Then, the determination of a biological protocol was carried out on the basis of pharmacokinetic studies. The experiments have shown the possibility to use the probe for radioactive measurements under intense magnetic field simultaneously to anatomical images acquisitions. Simultaneously, we have sought to improve the quantification of the radioactive signal using a voxelized phantom of a rat brain. Finally, the emergence of transgenic models led us to reproduce pharmacokinetic studies for the mouse and to develop voxelized mouse phantoms. (author)

  14. Spectrophotometric determination of association constant

    DEFF Research Database (Denmark)

    2016-01-01

    Least-squares 'Systematic Trial-and-Error Procedure' (STEP) for spectrophotometric evaluation of association constant (equilibrium constant) K and molar absorption coefficient E for a 1:1 molecular complex, A + B = C, with error analysis according to Conrow et al. (1964). An analysis of the Charg...

  15. Canagliflozin-Associated Acute Pancreatitis.

    Science.gov (United States)

    Verma, Rajanshu

    2016-01-01

    Canagliflozin is a new drug in class of sodium-glucose cotransporter 2 inhibitors used for treatment of type 2 diabetes mellitus. We describe a patient who developed moderately severe acute pancreatitis as an untoward consequence after being initiated on this drug. To the best of our knowledge, this is the first reported case of canagliflozin-associated acute pancreatitis in clinical literature.

  16. Molecular Mechanisms Underlying Associative Learning

    NARCIS (Netherlands)

    S.K.E. Koekkoek (Bas)

    2004-01-01

    textabstractThis thesis primarily attempts to solve some long standing issues regarding classical eyelid conditioning. More specifically, what is the specific role of cerebellar LTD in classical eyeblink conditioning, and how does the answer change the view on cerebellar functioning on associative mot

  17. Semantic graphs and associative memories.

    Science.gov (United States)

    Pomi, Andrés; Mizraji, Eduardo

    2004-12-01

    Graphs have been increasingly utilized in the characterization of complex networks from diverse origins, including different kinds of semantic networks. Human memories are associative and are known to support complex semantic nets; these nets are represented by graphs. However, it is not known how the brain can sustain these semantic graphs. The vision of cognitive brain activities, shown by modern functional imaging techniques, assigns renewed value to classical distributed associative memory models. Here we show that these neural network models, also known as correlation matrix memories, naturally support a graph representation of the stored semantic structure. We demonstrate that the adjacency matrix of this graph of associations is just the memory coded with the standard basis of the concept vector space, and that the spectrum of the graph is a code invariant of the memory. As long as the assumptions of the model remain valid this result provides a practical method to predict and modify the evolution of the cognitive dynamics. Also, it could provide us with a way to comprehend how individual brains that map the external reality, almost surely with different particular vector representations, are nevertheless able to communicate and share a common knowledge of the world. We finish presenting adaptive association graphs, an extension of the model that makes use of the tensor product, which provides a solution to the known problem of branching in semantic nets.

  18. Factors associated with asthma control.

    NARCIS (Netherlands)

    Vries, M.P. de; Bemt, E.A.J.M. van den; Lince, S.; Muris, J.W.M.; Thoonen, B.P.A.; Schayck, C.P. van

    2005-01-01

    The aim of this study was to evaluate which factors are associated with asthma control experienced by asthma patients. In a cross-sectional study patients aged 16-60 years with mild to moderate asthma were selected. The influence of the following factors on asthma control was studied in a multivaria

  19. Casein nomenclature, structure and association

    Science.gov (United States)

    This chapter of the Encyclopedia of Dairy Science deals with the recent developments in the nomenclature, classification, structures, and associations of the major milk proteins: the caseins. Identification of the caseins continues to be based upon their primary structures. Significant findings re...

  20. Strabismus-associated myopia. Review.

    Science.gov (United States)

    Hernández Martínez, P; Rodríguez Del Valle, J M

    2017-07-23

    The treatment of strabismus associated with myopia is often a therapeutic challenge for the ophthalmologist. The strabismus associated with myopia has certain peculiarities and there are even certain types of strabismus that occur exclusively in myopia, such as strabismus fixus, requiring treatments with specific surgical techniques. It is important to make a correct differential diagnosis, because there are many conditions described with this association. A review is presented of strabismus associated with myopia, together with its treatment adjusted to refractive error. Measurements of strabismus may be altered by the prismatic effect of the spectacles. Surgical results may be unpredictable if myopia is not taken into account. Better results were obtained with the techniques of anatomical replacement described by Yokoyama than with traditional retro-insertion-resection. For the diagnosis and appropriate treatment of strabismus, it is important to make a correct measurement of the angle of deviation, and perform image tests prior to surgery in certain cases. The anatomical characteristics of the myopic eye should also be taken into account during surgery. Copyright © 2017 Sociedad Española de Oftalmología. Publicado por Elsevier España, S.L.U. All rights reserved.

  1. Molecular Mechanisms Underlying Associative Learning

    NARCIS (Netherlands)

    S.K.E. Koekkoek (Bas)

    2004-01-01

    textabstractThis thesis primarily attempts to solve some long standing issues regarding classical eyelid conditioning. More specifically, what is the specific role of cerebellar LTD in classical eyeblink conditioning, and how does the answer change the view on cerebellar functioning on associative mot

  2. Spina Bifida Association of America

    Science.gov (United States)

    Exceptional Parent, 1974

    1974-01-01

    The Statement of the Spina Bifida Association of America (SBAA) explains SB as a malformation of the central nervous system, reports the formation of SBAA in 1974, explains SBAA's emphasis on local chapter organization, and describes SBAA services, including a bimonthly publication, public education efforts, and research validation projects. (GW)

  3. Ocular toxoplasmosis associated with scleritis

    Directory of Open Access Journals (Sweden)

    Yogish S Kamath

    2013-01-01

    Full Text Available We report an atypical presentation of Toxoplasma retinochoroiditis with associated scleritis in a young and immunocompetent patient. The diagnosis was done on the basis of Polymerase chain reaction of vitreous sample, and the clinical response to specific treatment. This case highlights the unusual presentation of ocular toxoplasmosis as scleritis.

  4. Medication-wide association studies

    NARCIS (Netherlands)

    P.B. Ryan (Patrick); D. Madigan (David); P.E. Stang (Paul); M.J. Schuemie (Martijn); G. Hripcsak (G.)

    2013-01-01

    textabstractUndiscovered side effects of drugs can have a profound effect on the health of the nation, and electronic health-care databases offer opportunities to speed up the discovery of these side effects. We applied a "medication-wide association study" approach that combined multivariate analys

  5. Exploring Entity Associations Over Time

    NARCIS (Netherlands)

    Reinanda, R.; Odijk, D.; de Rijke, M.

    2013-01-01

    We address the problem of entity-oriented search in the humanities and social sciences domain. We are particularly interested in retrieving entities related to a query entity and finding associations between these entities over time. Evidence from our target end users suggests that it is more inform

  6. Vitiligo associated with cutaneous amyloidosis

    Directory of Open Access Journals (Sweden)

    Rajkumar V

    2001-09-01

    Full Text Available Vitiligo is known to be associated with a variety of dermatoses and systemic diseases. We describe a case of vitiligo developing in a patient having cutaneous amyloidosis. To our knowledge this is the first report of its kind in the literature.

  7. Microfibrillar-Associated Protein 4

    DEFF Research Database (Denmark)

    Sækmose, Susanne Gjørup; Mössner, Belinda; Christensen, Peer Brehm

    2015-01-01

    BACKGROUND AND AIMS: A method for assessment of liver fibrosis and cirrhosis without the need for a liver biopsy is desirable. Microfibrillar-associated protein 4 (MFAP4) is a suggested biomarker for identification of high-risk patients with severe fibrosis stages. This study aimed to examine...

  8. Microfibrillar-associated protein 4

    DEFF Research Database (Denmark)

    Johansson, Sofie Lock; Roberts, Nassim Bazeghi; Schlosser, Anders

    2014-01-01

    BACKGROUND: Microfibrillar-associated protein 4 (MFAP4) is a matricellular glycoprotein that co-localises with elastic fibres and is highly expressed in the lungs. The aim of this study was to test the hypothesis that plasma MFAP4 (pMFAP4) reflects clinical outcomes in chronic obstructive pulmonary...

  9. The associative brain at work

    DEFF Research Database (Denmark)

    Suppa, A; Quartarone, A; Siebner, H

    2017-01-01

    The original protocol of Paired Associative Stimulation (PAS) in humans implies repetitive cortical and peripheral nerve stimuli, delivered at specific inter-stimulus intervals, able to elicit non-invasively long-term potentiation (LTP)- and long-term depression (LTD)-like plasticity in the human......-computer interface....

  10. Brain Injury Association of America

    Science.gov (United States)

    ... Only) 1-800-444-6443 Welcome to the Brain Injury Association of America (BIAA) Brain injury is not an event or an outcome. ... misunderstood, under-funded neurological disease. People who sustain brain injuries must have timely access to expert trauma ...

  11. Antibiotic associated diarrhoea: Infectious causes

    Directory of Open Access Journals (Sweden)

    Ayyagari A

    2003-01-01

    Full Text Available Nearly 25% of antibiotic associated diarrhoeas (AAD is caused by Clostridium difficile, making it the commonest identified and treatable pathogen. Other pathogens implicated infrequently include Clostridium perfringens, Staphylococcus aureus, Klebsiella oxytoca, Candida spp. and Salmonella spp. Most mild cases of AAD are due to non-infectious causes which include reduced break down of primary bile acids and decrease metabolism of carbohydrates, allergic or toxic effects of antibiotic on intestinal mucosa and pharmacological effect on gut motility. The antibiotics most frequently associated with C. difficile associated diarrhoea are clindamycin, cephalosporin, ampicillin and amoxicillin. Clinical presentation may vary from mild diarrhoea to severe colitis and pseudomembranous colitis associated with high morbidity and mortality. The most sensitive and specific diagnostic test for C. difficile infection is tissue culture assay for cytotoxicity of toxin B. Commercial ELISA kits are available. Though less sensitive, they are easy to perform and are rapid. Withdrawal of precipitating antibiotic is all that is needed for control of mild to moderate cases. For severe cases of AAD, oral metronidazole is the first line of treatment, and oral vancomycin is the second choice. Probiotics have been used for recurrent cases.

  12. Pseudobulbar palsy associated with trismus.

    OpenAIRE

    Lai, M M; Howard, R S

    1994-01-01

    A 60 year old patient presented with an acute pseudobulbar palsy associated with trismus. A computed tomography scan revealed low attenuation areas consistent with infarction affecting the genu of the internal capsules bilaterally. Trismus has not previously been described as the presenting feature of a pseudobulbar palsy.

  13. Multiple sclerosis associated with trismus.

    Science.gov (United States)

    D'Costa, D. F.; Vania, A. K.; Millac, P. A.

    1990-01-01

    This report describes the case history of a middle-aged lady who presented with symptoms and signs over one year leading to a diagnosis of multiple sclerosis. During one of her relapses, she developed trismus--an association that has not been described before in multiple sclerosis. PMID:2099430

  14. Pseudobulbar palsy associated with trismus.

    Science.gov (United States)

    Lai, M. M.; Howard, R. S.

    1994-01-01

    A 60 year old patient presented with an acute pseudobulbar palsy associated with trismus. A computed tomography scan revealed low attenuation areas consistent with infarction affecting the genu of the internal capsules bilaterally. Trismus has not previously been described as the presenting feature of a pseudobulbar palsy. Images Figure 1 PMID:7824418

  15. Kaposi sarcoma associated with lipoedema.

    Science.gov (United States)

    Ekmekci, T R; Ayabakan, O; Sakiz, D; Koslu, A

    2005-05-01

    Lipoedema is a form of lipodistrophy, which consists of abnormal accumulation of fat in subcutaneous tissue of the lower limbs. It does not cause any disease and it has not been reported association with malignity. We describe a 63-year-old woman occurring of Kaposi sarcoma on the lipoedema base.

  16. Factors associated with intern fatigue.

    Science.gov (United States)

    Friesen, Lindsay D; Vidyarthi, Arpana R; Baron, Robert B; Katz, Patricia P

    2008-12-01

    Prior data suggest that fatigue adversely affects patient safety and resident well-being. ACGME duty hour limitations were intended, in part, to reduce resident fatigue, but the factors that affect intern fatigue are unknown. To identify factors associated with intern fatigue following implementation of duty hour limitations. Cross-sectional confidential survey of validated questions related to fatigue, sleep, and stress, as well as author-developed teamwork questions. Interns in cognitive specialties at the University of California, San Francisco. Univariate statistics characterized the distribution of responses. Pearson correlations elucidated bivariate relationships between fatigue and other variables. Multivariate linear regression models identified factors independently associated with fatigue, sleep, and stress. Of 111 eligible interns, 66 responded (59%). In a regression analysis including gender, hours worked in the previous week, sleep quality, perceived stress, and teamwork, only poorer quality of sleep and greater perceived stress were significantly associated with fatigue (p 80 h was not significantly associated with perceived stress, quality of sleep, or fatigue. Simply decreasing the number of duty hours may be insufficient to reduce intern fatigue. Residency programs may need to incorporate programmatic changes to reduce stress, improve sleep quality, and foster teamwork in order to decrease intern fatigue and its deleterious consequences.

  17. Associated with Balkan Endemic Nephropathy

    Directory of Open Access Journals (Sweden)

    Ljubinka Jankovic-Velickovic

    2011-01-01

    Full Text Available The role of aristolochic acid in the etiology of Balkan endemic nephropathy (BEN and associated upper-tract urothelial carcinoma (UTUC has been recently confirmed. The aim of this study was to determine apoptosis-related marker(s specific for BEN-associated UTUC. Present investigation included 105 patients with UTUC, 44 from BEN region and 61 control tumors. Altered expression of Survivin was more often present in BEN UTUC with high grade and solid growth (P<0.005; P<0.05 than in control tumors. Significantly lower expression of proapoptotic marker Bax was found in BEN tumors with high grade, high stage, necrosis, and without metaplastic change (P<0.05; 0.05; 0.05; 0.05 compared to control tumors with the same features. Group (BEN-related/control, stage, growth pattern, and caspase 3 activity were significantly associated with the expression of Bax (P=0.002, 0.034, 0.047, 0.028, resp.,. This investigation identifies Bax as specific marker of BEN-associated UTUC. Decrease of pro-apoptotic protein Bax together with alteration of Survivin may be indicative for specific disturbances of intrinsic apoptotic pathway in UTUC arising in endemic areas.

  18. A European Social Simulation Association

    NARCIS (Netherlands)

    Moss, S

    2002-01-01

    This is a proposal to form a European Social Simulation Association (ESSA). ESSA is intended to coordinate with similar organisations in North America, Latin America and Australasia and other regions to organise an international federation to support the development of social simulation research, ed

  19. Medication-wide association studies

    NARCIS (Netherlands)

    P.B. Ryan (Patrick); D. Madigan (David); P.E. Stang (Paul); M.J. Schuemie (Martijn); G. Hripcsak (G.)

    2013-01-01

    textabstractUndiscovered side effects of drugs can have a profound effect on the health of the nation, and electronic health-care databases offer opportunities to speed up the discovery of these side effects. We applied a "medication-wide association study" approach that combined multivariate analys

  20. Spectrophotometric determination of association constant

    DEFF Research Database (Denmark)

    Spanget-Larsen, Jens

    2016-01-01

    Least-squares 'Systematic Trial-and-Error Procedure' (STEP) for spectrophotometric evaluation of association constant (equilibrium constant) K and molar absorption coefficient E for a 1:1 molecular complex, A + B = C, with error analysis according to Conrow et al. (1964). An analysis of the Charge...

  1. The International Big History Association

    Science.gov (United States)

    Duffy, Michael; Duffy, D'Neil

    2013-01-01

    IBHA, the International Big History Association, was organized in 2010 and "promotes the unified, interdisciplinary study and teaching of history of the Cosmos, Earth, Life, and Humanity." This is the vision that Montessori embraced long before the discoveries of modern science fleshed out the story of the evolving universe. "Big…

  2. Courses Associated with Freshman Learning.

    Science.gov (United States)

    Bohr, Louise

    1994-01-01

    This study examined the relationship of freshman courses to student (n=210) gains in reading, mathematics, and critical thinking skills. Courses were categorized according to broad discipline type (hard or soft, pure or applied), general field, or as individual courses. Freshman learning in mathematics appeared better associated with coursework…

  3. [IUD-associated abdominopelvic actinomycosis].

    Science.gov (United States)

    Anteby, E; Milvidsky, A; Goshen, R; Ben-Chetrit, A; Ron, M

    1991-09-01

    Abdominopelvic actinomycosis associated with the use of an intrauterine contraceptive device (IUD) is described. The diagnosis is usually made after exploratory laparotomy for severe abdominal pain and signs of an acute abdomen, or for prolonged lower abdominal pain and findings consistent with pelvic malignancy. 3 women aged 33, 44 and 52 years, respectively, are presented.

  4. Associative learning in biochemical networks.

    Science.gov (United States)

    Gandhi, Nikhil; Ashkenasy, Gonen; Tannenbaum, Emmanuel

    2007-11-07

    It has been recently suggested that there are likely generic features characterizing the emergence of systems constructed from the self-organization of self-replicating agents acting under one or more selection pressures. Therefore, structures and behaviors at one length scale may be used to infer analogous structures and behaviors at other length scales. Motivated by this suggestion, we seek to characterize various "animate" behaviors in biochemical networks, and the influence that these behaviors have on genomic evolution. Specifically, in this paper, we develop a simple, chemostat-based model illustrating how a process analogous to associative learning can occur in a biochemical network. Associative learning is a form of learning whereby a system "learns" to associate two stimuli with one another. Associative learning, also known as conditioning, is believed to be a powerful learning process at work in the brain (associative learning is essentially "learning by analogy"). In our model, two types of replicating molecules, denoted as A and B, are present in some initial concentration in the chemostat. Molecules A and B are stimulated to replicate by some growth factors, denoted as G(A) and G(B), respectively. It is also assumed that A and B can covalently link, and that the conjugated molecule can be stimulated by either the G(A) or G(B) growth factors (and can be degraded). We show that, if the chemostat is stimulated by both growth factors for a certain time, followed by a time gap during which the chemostat is not stimulated at all, and if the chemostat is then stimulated again by only one of the growth factors, then there will be a transient increase in the number of molecules activated by the other growth factor. Therefore, the chemostat bears the imprint of earlier, simultaneous stimulation with both growth factors, which is indicative of associative learning. It is interesting to note that the dynamics of our model is consistent with certain aspects of

  5. Covariance Association Test (CVAT) Identifies Genetic Markers Associated with Schizophrenia in Functionally Associated Biological Processes

    DEFF Research Database (Denmark)

    Rohde, Palle Duun; Demontis, Ditte; Castro Dias Cuyabano, Beatriz

    2016-01-01

    Schizophrenia is a psychiatric disorder with large personal and social costs, and understanding the genetic etiology is important. Such knowledge can be obtained by testing the association between a disease phenotype and individual genetic markers; however, such single-marker methods have limited...... genomic best linear unbiased prediction (GBLUP), the covariance association test (CVAT). We compared the performance of CVAT to other commonly used set tests. The comparison was conducted using a simulated study population having the same genetic parameters as for schizophrenia. We found that CVAT...... was among the top performers. When extending CVAT to utilize a mixture of SNP effects, we found an increase in power to detect the causal sets. Applying the methods to a Danish schizophrenia case–control data set, we found genomic evidence for association of schizophrenia with vitamin A metabolism...

  6. HTLV-1 Associated Neurological Disorders.

    Science.gov (United States)

    Khan, Muhammad Yasir; Khan, Ishaq Nasib; Farman, Muhammad; Al Karim, Saleh; Qadri, Ishtiaq; Kamal, Muhammad Amjad; Al Ghamdi, Khalid; Harakeh, Steve

    2017-01-01

    Human T-cell lymphotropic virus type 1 (HTLV-1) is a retrovirus which is endemic to certain regions of the world and infects around 10-20 million people. HTLV-1 is the etiologic agent of Adult T cell leukemia/lymphoma and HTLV-1 associated neurological disorders including mainly HTLV-1 associated myelopathy/Tropical spastic paraparesis. The involvement of the central nervous diseases occurs among: HTLV-1 infected patients from endemic areas, HIV positive individuals and drug users. The ability of HTLV-1 to cause associated neuropathies starts with the virus crossing the blood brain barrier (BBB), then entering and infecting the cells of the central nervous system. As a consequence, to the viral attack, HTLV-1 infected lymphocytes produce pro-inflammatory cytokines like tumor necrosis factor alpha, Interleukin 1 beta and interleukin 6 which further disrupts the BBB. Different serological tests have been used in the diagnosis of HTLV-1. These include: ELISA, Western Blotting (WB), Immunofluorescence, Particle Agglutination and Polymerase Chain Reaction which is used as a confirmatory test. Danazol, pentoxifylline, azathioprine and vitamin C have been used in the treatment of the HTLV-1 associated neurological disorders. Other antiviral drugs (lamivudine, zidovudine), monoclonal antibodies (Daclizumab) and therapeutic agents (valporic acid, interferons) have also been evaluated. No known drug, so far, has been shown to be efficacious. The aim of this review is to present the complexities of HTLV-1 associated neurological disorders and their current ongoing treatment. In addition to discussing future possible therapeutic strategies, by targeting HTVL-1 viral components and gene/s products, for the treatment of those neurological conditions. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  7. 12 CFR 619.9050 - Associations.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Associations. 619.9050 Section 619.9050 Banks and Banking FARM CREDIT ADMINISTRATION FARM CREDIT SYSTEM DEFINITIONS § 619.9050 Associations. The... credit associations, production credit associations, and agricultural credit associations....

  8. Associative Cones and Integrable Systems

    Institute of Scientific and Technical Information of China (English)

    Chuu-Lian TERNG; Shengli KONG; Erxiao WANG

    2006-01-01

    We identify R7 as the pure imaginary part of octonions. Then the multiplication in octonions gives a natural almost complex structure for the unit sphere S6. It is known that a cone over a surface M in S6 is an associative submanifold of R7 if and only if M is almost complex in S6. In this paper, we show that the Gauss-Codazzi equation for almost complex curves in S6 are the equation for primitive maps associated to the 6-symmetric space G2/T2, and use this to explain some of the known results. Moreover, the equation for S1-symmetric almost complex curves in S6 is the periodic Toda lattice, and a discussion of periodic solutions is given.

  9. Association theories for complex thermodynamics

    DEFF Research Database (Denmark)

    Kontogeorgis, Georgios; Rafiqul Gani

    2013-01-01

    Thermodynamics of complex systems (e.g. with associating molecules, multicomponent mixtures, multiphase equilibria, wide ranges of conditions, estimation of many different properties simultaneously) is a topic of great importance in chemical engineering and for a wide range of industrial...... promising direction for a general and useful for engineering purposes modeling of complex thermodynamics is via the use of association theories e.g. those based on chemical theory (like APACT), or on the lattice theory (like NRHB) or those based on perturbation theory (like SAFT and CPA). The purpose...... applications. While specialized models can handle different cases, even complex ones, with the advent of powerful theories and computers there is the hope that a single or a few models could be suitable for a general modeling of complex thermodynamics. After more than 100 years with active use of thermodynamic...

  10. Associativity and normative credal probability.

    Science.gov (United States)

    Snow, P

    2002-01-01

    Cox's Theorem is a widely cited motivation for probabilistic models of uncertain belief. The theorem relates the associativity of the logical connectives to that of the arithmetic operations of probability. Recent questions about the correctness of Cox's Theorem have been resolved, but there are new questions about one functional equation used by Cox in 1946. This equation is missing from his later work. Advances in knowledge since 1946 and changes in Cox's research interests explain the equation's disappearance. Other associativity-based motivations avoid functional equations altogether, and so may be more transparently applied to finite domains and discrete beliefs. A discrete counterpart of Cox's Theorem can be assembled from results that have been in the literature since 1959.

  11. Pattern Recognition Using Associative Memories

    OpenAIRE

    Burles, Nathan John

    2014-01-01

    The human brain is extremely effective at performing pattern recognition, even in the presence of noisy or distorted inputs. Artificial neural networks attempt to imitate the structure of the brain, often with a view to mimicking its success. The binary correlation matrix memory (CMM) is a particular type of neural network that is capable of learning and recalling associations extremely quickly, as well as displaying a high storage capacity and having the ability to generalise from patterns a...

  12. Seven fatalities associated with ethylphenidate

    OpenAIRE

    Maskell, Peter D.; Smith, Paul; Cole, Richard; Hikin, Laura; Morley, Stephen

    2016-01-01

    Ethylphenidate is a stimulant novel psychoactive substance that is an analogue of the prescription drug methylphenidate (Ritalin®). Methylphenidate is used commonly for the treatment of attention deficit hyperactivity disorder. Due to its stimulant effects ethylphenidate is being abused. There is a single case report of a death associated with ethylphenidate in Germany, and a case series of 19 deaths in the East of Scotland, but otherwise, the contribution of ethylphenidate to death is poorly...

  13. Lithium-Associated Kidney Microcysts

    OpenAIRE

    Jennifer Tuazon; David Casalino; Ehteshamuddin Syed; Daniel Batlle

    2008-01-01

    Long-term lithium therapy is associated with impairment in concentrating ability and, occasionally, progression to advanced chronic kidney disease from tubulointerstitial nephropathy. Biopsy findings in patients with lithium-induced chronic tubulointerstitial nephropathy include tubular atrophy and interstitial fibrosis interspersed with tubular cysts and dilatations. Recent studies have shown that cysts are seen in 33––62.5% of the patients undergoing lithium therapy. MR imaging is highly ca...

  14. American Psychological Association annual report.

    Science.gov (United States)

    2010-01-01

    Presents the 2009 American Psychological Association annual report. It highlights a very important year for APA and psychology by summarizing activities within each directorate. It describes strides made toward the goal of infusing psychology into the health care marketplace and of bringing psychology-and the unique skills of psychologists-to the attention of the public. This report aims to give insight into the contributions psychologists make to our communities and our country. 2010 APA, all rights reserved.

  15. Carpathian-Balkan Geological Association

    Institute of Scientific and Technical Information of China (English)

    Aleksandar Grubic

    2006-01-01

    @@ Carpathian-Balkan Geological Association (CBGA), according to its Statute, "is non-governmental, international, scientific, non-political and non-profit making union of geoscientists working in the Carpathian-Balkan realm" and surrounding areas. The membership of CBGA is collective and it is "open to geoscientists of all countries of the Carpathian-Balkan" and neighboring countries. Application of collective membership "should be submitted by competent scientific bodies".

  16. Clostridium difficile-associated colitis.

    OpenAIRE

    Hull, Mark W.; Beck, Paul L.

    2004-01-01

    OBJECTIVE: To review the basic microbiology, pathogenesis of disease, and diagnosis of the nosocomial pathogen Clostridium difficile and to examine therapies recommended by the Canadian Task Force on Preventive Health Care. QUALITY OF EVIDENCE MEDLINE: was searched using MeSH headings. Controlled trials for therapy were sought, but case-control studies and observational reviews were included. MAIN MESSAGE: Clostridium difficile causes approximately 20% of cases of diarrhea associated with ant...

  17. Ion association in natural brines

    Science.gov (United States)

    Truesdell, A.H.; Jones, B.F.

    1969-01-01

    Natural brines, both surface and subsurface, are highly associated aqueous solutions. Ion complexes in brines may be ion pairs in which the cation remains fully hydrated and the bond between the ions is essentially electrostatic, or coordination complexes in which one or more of the hydration water molecules are replaced by covalent bonds to the anion. Except for Cl-, the major simple ions in natural brines form ion pairs; trace and minor metals in brines form mainly coordination complexes. Limitations of the Debye-Hu??ckel relations for activity coefficients and lack of data on definition and stability of all associated species in concentrated solutions tend to produce underestimates of the degree of ion association, except where the brines contain a very high proportion of Cl-. Data and calculations on closed basin brines of highly varied composition have been coupled with electrode measurements of single-ion activities in an attempt to quantify the degree of ion association. Such data emphasize the role of magnesium complexes. Trace metal contents of closed basin brines are related to complexes formed with major anions. Alkaline sulfo- or chlorocarbonate brines (western Great Basin) carry significant trace metal contents apparently as hydroxides or hydroxy polyions. Neutral high chloride brines (Bonneville Basin) are generally deficient in trace metals. With a knowledge of the thermodynamic properties of a natural water, many possible reactions with other phases (solids, gases, other liquids) may be predicted. A knowledge of these reactions is particularly important in the study of natural brines which may be saturated with many solid phases (silicates, carbonates, sulfates, etc.), which may have a high pH and bring about dissolution of other phases (silica, amphoteric hydroxides, CO2, etc.), and which because of their high density may form relatively stable interfaces with dilute waters. ?? 1969.

  18. Obesity-associated cancer: an immunological perspective

    National Research Council Canada - National Science Library

    Conroy, Melissa J; Dunne, Margaret R; Donohoe, Claire L; Reynolds, John V

    2016-01-01

    ... obesity-associated cancer. This review addresses key immune cell subsets underpinning obesity-associated inflammation and describes how such immune compartments might be targeted to prevent and treat obesity-associated cancer...

  19. Pathogenesis of PR3-ANCA associated vasculitis

    NARCIS (Netherlands)

    Kallenberg, C. G. M.

    2008-01-01

    Wegener's Granulomatosis (WG) is closely associated with antineutrophil cytoplasmic autoantibodies (ANCA), particularly those directed to proteinase 3 (PR3). ANCA directed to myeloperoxidase (MPO) are associated with microscopic polyangiitis (MPA) and the Churg Strauss syndrome. PR3-ANCA associated

  20. Pathogenesis of PR3-ANCA associated vasculitis

    NARCIS (Netherlands)

    Kallenberg, C. G. M.

    2008-01-01

    Wegener's Granulomatosis (WG) is closely associated with antineutrophil cytoplasmic autoantibodies (ANCA), particularly those directed to proteinase 3 (PR3). ANCA directed to myeloperoxidase (MPO) are associated with microscopic polyangiitis (MPA) and the Churg Strauss syndrome. PR3-ANCA associated

  1. Problems associated with shellfish farming.

    Science.gov (United States)

    Chinabut, S; Somsiri, T; Limsuwan, C; Lewis, S

    2006-08-01

    Shellfish culture is a major sector of aquaculture production worldwide, and zoonoses and drug residues associated with shellfish farm practice are of concern to public health. This paper focuses on three of the most important shellfish species: molluscs, crabs and shrimp. Although many diseases can affect shellfish, they do not appear to be transmittable to humans. Rather, the main hazards are associated with the methods used to farm the different species. The risk to human health from shellfish most commonly relates to contamination by biotoxins produced by marine algae. Another well-recognised problem associated with shellfish culture is the contamination of shellfish with domestic sewage that contains human pathogenic bacteria and viruses, which causes diseases such as typhoid fever and hepatitis. In shrimp farming, the main potential food safety hazards are zoonoses, chemical contamination and veterinary drug residues. Untreated effluent from shrimp farms is a major concern to the environmental sector as it is known to promote plankton blooms if directly discharged into natural water sources.

  2. Why join the Staff Association

    CERN Multimedia

    Association du personnel

    2011-01-01

    Becoming a member of the Staff Association (SA) is above all a personal choice, showing that the joining person’s commitment and adherence to values such as solidarity, social cohesion, etc.In September, the SA launches a membership campaign to convince a maximum number to join, to inform, arouse interest and support. Posters, emails and individual contacts are part of the campaign programme, just like this editorial. As far as individual contacts are concerned, we ask you to give time and lend an ear to the delegates of your department in the Staff Council, who will approach you, in order to make an open and constructive discussion possible. Do not hesitate to ask questions and let them know your thoughts about the SA, as (constructive) criticism enables us to progress. The Staff Association and its role of collective representation The Staff Association, via its delegates, represents collectively all staff of the Organization before the Director-General and Member States. To do this, staff rep...

  3. A Study on Associative Neural Memories

    OpenAIRE

    B.D.C.N.Prasad; P. E. S. N. Krishna Prasad; Sagar Yeruva; P Sita Rama Murty

    2011-01-01

    Memory plays a major role in Artificial Neural Networks. Without memory, Neural Network can not be learned itself. One of the primary concepts of memory in neural networks is Associative neural memories. A survey has been made on associative neural memories such as Simple associative memories (SAM), Dynamic associative memories (DAM), Bidirectional Associative memories (BAM), Hopfield memories, Context Sensitive Auto-associative memories (CSAM) and so on. These memories can be applied in vari...

  4. Pathogenesis and Associated Diseases of Kaposi's Sarcoma-associated Herpesvirus

    Institute of Scientific and Technical Information of China (English)

    Lin-ding WANG

    2007-01-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) is the primary etiological agent of Kaposi's sarcoma, primary effusion lymphoma and muticentric Castleman's disease. In common with the other herpesviruses, KSHV exhibits both latent and lytic life cycles, both of which are characterized by distinct gene expression profiles and programs. KSHV encodes proteins which play essential roles in the inhibition of host adaptive and innate immunity, the inhibition of apoptosis, and the regulation of the cell cycle. KSHV also encodes several proteins which have transforming and intrcellular signalling activity.

  5. Covariance Association Test (CVAT) Identifies Genetic Markers Associated with Schizophrenia in Functionally Associated Biological Processes

    DEFF Research Database (Denmark)

    Rohde, Palle Duun; Demontis, Ditte; Castro Dias Cuyabano, Beatriz;

    2016-01-01

    Schizophrenia is a psychiatric disorder with large personal and social costs, and understanding the genetic etiology is important. Such knowledge can be obtained by testing the association between a disease phenotype and individual genetic markers; however, such single-marker methods have limited...... power to detect genetic markers with small effects. Instead, aggregating genetic markers based on biological information might increase the power to identify sets of genetic markers of etiological significance. Several set test methods have been proposed: Here we propose a new set test derived from...... genomic best linear unbiased prediction (GBLUP), the covariance association test (CVAT). We compared the performance of CVAT to other commonly used set tests. The comparison was conducted using a simulated study population having the same genetic parameters as for schizophrenia. We found that CVAT...

  6. NNLOPS accurate associated HW production

    CERN Document Server

    Astill, William; Re, Emanuele; Zanderighi, Giulia

    2016-01-01

    We present a next-to-next-to-leading order accurate description of associated HW production consistently matched to a parton shower. The method is based on reweighting events obtained with the HW plus one jet NLO accurate calculation implemented in POWHEG, extended with the MiNLO procedure, to reproduce NNLO accurate Born distributions. Since the Born kinematics is more complex than the cases treated before, we use a parametrization of the Collins-Soper angles to reduce the number of variables required for the reweighting. We present phenomenological results at 13 TeV, with cuts suggested by the Higgs Cross Section Working Group.

  7. Rifampin-associated pseudomembranous colitis.

    Science.gov (United States)

    Chen, Tun-Chieh; Lu, Po-Liang; Lin, Wei-Ru; Lin, Chun-Yu; Wu, Jeng-Yih; Chen, Yen-Hsu

    2009-08-01

    Pseudomembranous colitis (PMC) is known to develop after antibiotic treatment, but is rarely associated with antituberculosis (anti-TB) agents. We report a 28-year-old woman without underlying diseases developing PMC after 126 days of anti-TB treatment. Severe diarrhea and abdominal cramping pain were experienced. Colonoscopic biopsy proved the diagnosis of PMC. Her symptoms improved after discontinuing the anti-TB agents but recurred shortly after challenging with rifampin and isoniazid. Metronidazole administration and replacement of rifampin with levofloxacin successfully cured the PMC. Our report supports the notion that rifampin can induce PMC.

  8. Poliosis circumscripta associated with neurofibroma.

    Science.gov (United States)

    Kwon, In Ho; Cho, Young Joon; Lee, Seung Ho; Lee, Jong Hee; Cho, Kwang Hyun; Kim, Jeong Aee; Moon, Sang Eun

    2005-06-01

    A 32-year-old woman presented at our clinic with a moderately soft, nontender, subcutaneous mass in the left temporal region and white hairs overlying the swelling. The lesion was surgically excised, and there was no recurrence at one year postoperatively. On histological examination, the hair follicles overlying the subcutaneous mass were devoid of pigment and a poorly demarcated fibrocellular process was seen in the subcutaneous mass, which was typical of neurofibroma. To our knowledge, only one case of poliosis associated with neurofibroma has been previously reported.

  9. Malaria-associated peripheral gangrene

    Directory of Open Access Journals (Sweden)

    Deborah B. Martins

    2014-09-01

    Full Text Available Malaria is a common parasitic disease endemic in tropical and subtropical areas, including Mozambique. Symmetrical peripheral gangrene is a rare complication of malaria. The purpose of this study was to review cases of malaria-associated peripheral gangrene that were evaluated by the pediatric surgical service at Hospital Central. Four patients ranging in age from 11 months to 7 years with documented Plasmodium falciparum infection and peripheral gangrene were identified. Amputation was required in cases of wet-gangrene. The majority of cases were allowed to self-demarcate, and one was allowed to auto-amputate.

  10. Radiation-associated valvular disease

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, R.G.; Mayfield, W.R.; Normann, S.; Alexander, J.A. (Univ. of Florida, Gainesville (USA))

    1991-03-01

    The prevalence of radiation-associated cardiac disease is increasing due to prolonged survival following mediastinal irradiation. Side effects of radiation include pericarditis, accelerated coronary artery disease, myocardial fibrosis and valvular injury. We evaluated the cases of three young patients with evidence of significant valvular disease following mediastinal irradiation. One patient underwent the first reported successful aortic and mitral valve replacement for radiation-associated valvular disease (RAVD) as well as concurrent coronary artery revascularization. A review of the literature revealed 35 reported cases of RAVD, with only one successful case of valve replacement that was limited to the aortic valve. Asymptomatic RAVD is diagnosed 11.5 years after mediastinal irradiation compared with 16.5 years for symptomatic patients, emphasizing that long-term follow-up is important for patients receiving mediastinal irradiation. This study defines a continuum of valvular disease following radiation that begins with mild asymptomatic valvular thickening and progresses to severe valvular fibrosis with hemodynamic compromise requiring surgical intervention. 32 refs.

  11. Genetic Syndromes Associated with Craniosynostosis.

    Science.gov (United States)

    Ko, Jung Min

    2016-05-01

    Craniosynostosis is defined as the premature fusion of one or more of the cranial sutures. It leads not only to secondary distortion of skull shape but to various complications including neurologic, ophthalmic and respiratory dysfunction. Craniosynostosis is very heterogeneous in terms of its causes, presentation, and management. Both environmental factors and genetic factors are associated with development of craniosynostosis. Nonsyndromic craniosynostosis accounts for more than 70% of all cases. Syndromic craniosynostosis with a certain genetic cause is more likely to involve multiple sutures or bilateral coronal sutures. FGFR2, FGFR3, FGFR1, TWIST1 and EFNB1 genes are major causative genes of genetic syndromes associated with craniosynostosis. Although most of syndromic craniosynostosis show autosomal dominant inheritance, approximately half of patients are de novo cases. Apert syndrome, Pfeiffer syndrome, Crouzon syndrome, and Antley-Bixler syndrome are related to mutations in FGFR family (especially in FGFR2), and mutations in FGFRs can be overlapped between different syndromes. Saethre-Chotzen syndrome, Muenke syndrome, and craniofrontonasal syndrome are representative disorders showing isolated coronal suture involvement. Compared to the other types of craniosynostosis, single gene mutations can be more frequently detected, in one-third of coronal synostosis patients. Molecular diagnosis can be helpful to provide adequate genetic counseling and guidance for patients with syndromic craniosynostosis.

  12. Hyperthyroidism-associated hypercalcemic crisis

    Science.gov (United States)

    Chen, Ke; Xie, Yanhong; Zhao, Liling; Mo, Zhaohui

    2017-01-01

    Abstract Rationale: Hyperthyroidism is one of the major clinical causes of hypercalcaemia, however, hyperthyroidism-related hypercalcemic crisis is rare, only 1 case have been reported. The potential mechanisms are still not too clear. It may be related that thyroid hormone stimulate bone turnover, elevate serum calcium, increase urinary and fecal calcium excretion. Patient concerns: A 58-year-old female patient was found to have Graves’ disease, a marked elevated serum calcium level (adjusted serum calcium: 3.74 mmol/L), and reduced parathyroid hormone level. Diagnoses: She was diagnosed as hyperthyroidism-associated hypercalcemic crisis. Interventions: Treatment with methimazole to correct the hyperthyroidism and treatment of the patient's hypercalcaemia was achieved by physiological saline, salmon calcitonin and furosemide. Outcomes: After treatment for hypercalcaemia and hyperthyroidism, her symptoms and serum calcium levels quickly returned to normal. Lessons: hyperthyroid-associated hypercalcaemia crisis is rare, however, the diagnosis should pay attention to screening for other diseases caused by hypercalcemia. Timely treatment of hypercalcaemia is a critical step for rapidly control of symptoms, and treatment of hyperthyroidism is beneficial to relief the symptoms and maintain the blood calcium level. PMID:28121960

  13. Association and determinacy in geomorphology

    Science.gov (United States)

    Leopold, Luna Bergere; Langbein, Walter Basil; Albritton, Claude C.

    1963-01-01

    You find a rock. It looks like an ordinary piece of flint, broken and rough. On a part of it is a patina whose soft grey color contrasts with the shiny brownish surfaces of conchoidal fracture. You could have found this rock in nearly any kind of an environment almost anyplace in the world. There is nothing distinctive about it.You hand this same piece of rock to a colleague and ask what he can make of it. He considers it soberly before he says, “You know, that could be an artifact.” There springs to mind then a picture of a primitive man, squatting barefoot before a fire warming his hands. The firelight casts his shadow against the cliff below which he crouches. The difference between the reaction before and after the passing thought that this might indeed be the tool of ancient man is the difference between mild disinterest and a kaleidoscope of mental pictures. This difference reflects differences in the associations of thoughts. The present essay is concerned with how associations are used in geologic reasoning, and then with certain philosophic considerations which seem to be influencing the methodology and direction of geomorphology.

  14. Zika Virus Associated with Microcephaly.

    Science.gov (United States)

    Mlakar, Jernej; Korva, Misa; Tul, Nataša; Popović, Mara; Poljšak-Prijatelj, Mateja; Mraz, Jerica; Kolenc, Marko; Resman Rus, Katarina; Vesnaver Vipotnik, Tina; Fabjan Vodušek, Vesna; Vizjak, Alenka; Pižem, Jože; Petrovec, Miroslav; Avšič Županc, Tatjana

    2016-03-10

    A widespread epidemic of Zika virus (ZIKV) infection was reported in 2015 in South and Central America and the Caribbean. A major concern associated with this infection is the apparent increased incidence of microcephaly in fetuses born to mothers infected with ZIKV. In this report, we describe the case of an expectant mother who had a febrile illness with rash at the end of the first trimester of pregnancy while she was living in Brazil. Ultrasonography performed at 29 weeks of gestation revealed microcephaly with calcifications in the fetal brain and placenta. After the mother requested termination of the pregnancy, a fetal autopsy was performed. Micrencephaly (an abnormally small brain) was observed, with almost complete agyria, hydrocephalus, and multifocal dystrophic calcifications in the cortex and subcortical white matter, with associated cortical displacement and mild focal inflammation. ZIKV was found in the fetal brain tissue on reverse-transcriptase-polymerase-chain-reaction (RT-PCR) assay, with consistent findings on electron microscopy. The complete genome of ZIKV was recovered from the fetal brain.

  15. Acute whiplash associated disorders (WAD

    Directory of Open Access Journals (Sweden)

    Kumar S

    2011-04-01

    Full Text Available Khushnum Pastakia, Saravana KumarInternational Centre for Allied Health Evidence, University of South Australia, Adelaide, SA, Australia Date of preparation: 27th January 2011Conflict of interest: None declaredBackground: Whiplash-associated disorder (WAD is the term given for the collection of symptoms affecting the neck that are triggered by an accident with an acceleration–deceleration mechanism such as a motor vehicle accident. The incidence of whiplash injury varies greatly between different parts of the world with significant monetary burden on the individual as well as the wider community.Objective: Which treatments are best for reducing pain and disability experience in acute WADs?Level of evidence: Clinical practice guidelines, systematic reviews, meta-analysis, randomized controlled trials.Search sources: PubMed, Cochrane Library, Medline, EMBASE, AUST health, AMED.Outcomes: From the patient perspective the main outcomes considered are pain and disability.Consumer summary: Whiplash-associated disorders include a range of symptoms related to the neck and head. They commonly occur after motor vehicle accidents or diving mishaps. There is good evidence to suggest that active exercise, acting as usual and combination therapy are the most effective treatment choices in an acute presentation.Keywords: whiplash, neckpain, pain levels, multimodel therapy

  16. [Atypical neuropathies associated with diabetes].

    Science.gov (United States)

    Lozeron, P

    2014-12-01

    Diabetes is the leading cause of neuropathy worldwide and, due to the epidemic progression of the affection, prevalence of diabetic neuropathies will increase in the near future. Beside the typical diabetic neuropathy pattern and the common entrapment neuropathies, several unusual clinical forms have been described with either a symmetrical or an asymmetrical pattern. Treatment-induced neuropathy is an acute sensory affection most commonly related to acute glycemic control. Pain is debilitating and associated with vegetative dysfunction. Prevention is important, as resolution is often incomplete. Several patterns or asymmetrical neuropathies of inflammatory and ischemic origin were described long ago in the lower limb. They are debilitating, most often painful and require steroid treatment. Other patterns affecting the thoracolumbar region or the upper limbs or involving a painless motor deficit must be identified as specific treatments are sometimes needed. An association between diabetes and chronic inflammatory demyelinating polyneuropathy has not been demonstrated but diagnosis may be suggested due to the misleading low conduction velocities seen in classical diabetic neuropathy. Like any other patient, the diabetic patient may present a neuropathy unrelated to diabetes. To facilitate patient care, neurologists should be aware of such clinical entities. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  17. 47 CFR 69.603 - Association functions.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Association functions. 69.603 Section 69.603... Exchange Carrier Association § 69.603 Association functions. (a) The Association shall not engage in any... functions pursuant to § 69.603 (c)-(g), and those expenses that pertain to Commission proceedings...

  18. 25 CFR 700.722 - Grazing associations.

    Science.gov (United States)

    2010-04-01

    ... recognition by the Commissioner are: (1) The members of the association must be grazing permittees and.... (d) The Commissioner may withdraw his recognition of the association whenever: (1) The majority of... constitution and bylaws. All of the association's livestock will be run under an association brand properly...

  19. International Conference on Computing Methods in Applied Sciences and Engineering (9th) Held in Paris, France on 29 January-2 February 1990

    Science.gov (United States)

    1990-02-02

    ULTION NUMERIQUE EN PHYSIQUE ET CHIMIE COMPUTA TIONAL PHYSICS AND CHEMISTRY_~ Localized basis functions and other computational Improvements in...La r6solution des problbmes complexes issus do la simulation num~rique en hypersonique, en micro- 6lectronique, en chimie quantique , en combustion ou...Science, Courant Inst.. New York University, 1986. 344 SIMULATION NUMERIQUE EN PHYSIQUE ET CHIMIE COMPUTATIONAL PHYSICS AND CHEMISTRY tI Localized

  20. Lie Admissible Non-Associative Algebras

    Institute of Scientific and Technical Information of China (English)

    H.Mohammad Ahmadi; Ki-Bong Nam; Jonathan Pakinathan

    2005-01-01

    A non-associative ring which contains a well-known associative ring or Lie ring is interesting. In this paper, a method to construct a Lie admissible non-associative ring is given; a class of simple non-associative algebras is obtained; all the derivations of the non-associative simple N0,0,1 algebra defined in this paper are determined; and finally, a solid algebra is defined.

  1. Epidemiology of ANCA associated vasculitis

    Directory of Open Access Journals (Sweden)

    Wenche Koldingsnes

    2009-10-01

    Full Text Available ANCA associated vasculitis (AAV comprises three syndromes with systemic vasculitis (Wegener’s granulomatosis (WG, Churg Strauss syndrome (CSS and icroscopic polyangiitis (MPA, which all involve small and medium sized vessels and are associated with antibodies against cytoplasmatic antibodies in neutrophils (ANCA. Polyarteritis nodosa (PAN is included in this review as it also affects medium sized vessels, and has many clinical findings in common with the AAV.Since the recognition of ANCA, increasing data have become available on the epidemiology of these vasculitidis. WG constitutes half of the AAV and its prevalence has increased from 30/million in the late 1980’s in the USA to 160/million in this century in northern Europe. The prevalence for the whole group of primary systemic vasculitides is now 300/million in Sweden. The annual incidence of WG increased from 6.0/million to 14/million during the 1990’s in Tromsø, but it is unknown if this is a true increase or the result of an increased awareness of the diagnosis. For the whole group of AAV, the annual incidence in most more recent studies is relatively constant over time and by geographical location, ranging from 13 to 21/million. Nonetheless there are interesting differences in the prevalence of specific vasculitis between different geographical areas, as well as for sub specificities of ANCA.There seems to be a South-North gradient for WG and PR3-ANCA with high figures reported from northern Europe and southern New Zealand. In European studies WG is 90% PR3-ANCA positive. MPA which is predominantly MPO-ANCA associated are more frequent in the Mediterranean countries and also has an increasing gradient towards east-Asia, as almost all AAV in China and Japan are diagnosed as MPA, predominantly MPO-ANCA positive.There are also some ethnic and gender differences. WG is most prevalent among Caucasians in the USA and in people with European ancestors in Paris and in New Zealand, less

  2. Pseudopheochromocytoma Associated with Domestic Assault

    Science.gov (United States)

    Le, H. M.; Carbutti, G.; Ilisei, D.; Bouccin, E.

    2016-01-01

    Pseudopheochromocytoma has a clinical presentation that is similar to pheochromocytoma. It manifests itself with paroxysmal hypertension crises, associated with various symptoms such as headaches, chest pain, nausea, palpitations, and dizziness. Patients are usually asymptomatic in between the crises. Unlike pheochromocytoma, there is no catecholamines overproduction in this pathology: hypertensive peaks are caused by a hyperactivation of the sympathetic nervous system, which is often triggered by a psychological trauma in the past. Treatment of pseudopheochromocytoma can be challenging due to normal blood pressure values in between the hypertensive peaks; it includes alpha- and beta-blockers for moderate crises and prevention and must be combined with psychopharmacologic agents such as anxiolytics or antidepressant drugs. Psychotherapy and dietetic treatment are also crucial in pseudopheochromocytoma management.

  3. Association between Frailty and Dementia

    DEFF Research Database (Denmark)

    Kulmala, J; Nykänen, I; Mänty, Minna Regina;

    2014-01-01

    logistic regression. Results: A total of 93 (14%) participants were classified as frail. Cognitive impairment (MMSE score Alzheimer's disease, 19 (3%) had vascular dementia, 12 (2%) had.......0-15.9), almost 6 times more likely to have vascular dementia (OR 5.6, 95% CI 1.2-25.8) and over 4 times more likely to have Alzheimer's disease (OR 4.5, 95% CI 2.1-9.6) than persons who were robust. Conclusion: Frailty is strongly associated with cognitive impairment and clinically diagnosed dementia among...... persons aged 76 and older. It is possible that cognitive impairment is a clinical feature of frailty and therefore should be included in the frailty definition....

  4. Diseases associated with leaky hemichannels

    Science.gov (United States)

    Retamal, Mauricio A.; Reyes, Edison P.; García, Isaac E.; Pinto, Bernardo; Martínez, Agustín D.; González, Carlos

    2015-01-01

    Hemichannels (HCs) and gap junction channels (GJCs) formed by protein subunits called connexins (Cxs) are major pathways for intercellular communication. While HCs connect the intracellular compartment with the extracellular milieu, GJCs allow the interchange of molecules between cytoplasm of two contacting cells. Under physiological conditions, HCs are mostly closed, but they can open under certain stimuli allowing the release of autocrine and paracrine molecules. Moreover, some pathological conditions, like ischemia or other inflammation conditions, significantly increase HCs activity. In addition, some mutations in Cx genes associated with human diseases, such as deafness or cataracts, lead to the formation of more active HCs or “leaky HCs.” In this article we will revise cellular and molecular mechanisms underlying the appearance of leaky HCs, and the consequences of their expression in different cellular systems and animal models, in seeking a common pattern or pathological mechanism of disease. PMID:26283912

  5. Visual hallucinations associated with zonisamide.

    Science.gov (United States)

    Akman, Cigdem I; Goodkin, Howard P; Rogers, Donald P; Riviello, James J

    2003-01-01

    Zonisamide is a broad-spectrum antiepileptic drug used to treat various types of seizures. Although visual hallucinations have not been reported as an adverse effect of this agent, we describe three patients who experienced complex visual hallucinations and altered mental status after zonisamide treatment was begun or its dosage increased. All three had been diagnosed earlier with epilepsy, and their electroencephalogram (EEG) findings were abnormal. During monitoring, visual hallucinations did not correlate with EEG readings, nor did video recording capture any of the described events. None of the patients had experienced visual hallucinations before this event. The only recent change in their treatment was the introduction or increased dosage of zonisamide. With either discontinuation or decreased dosage of the drug the symptoms disappeared and did not recur. Further observations and reports will help clarify this adverse effect. Until then, clinicians need to be aware of this possible complication associated with zonisamide.

  6. Diseases associated with leaky hemichannels.

    Directory of Open Access Journals (Sweden)

    Mauricio Antonio Retamal

    2015-07-01

    Full Text Available Hemichannels (HCs and gap junction channels (GJCs formed by protein subunits called connexins (Cxs are major pathways for intercellular communication. While HCs connect the intracellular compartment with the extracellular milieu, GJCs allow the interchange of molecules between cytoplasm of two contacting cells. Under physiological conditions, HCs are mostly closed, but they can open under certain stimuli allowing the release of autocrine and paracrine molecules. Moreover, some pathological conditions, like ischemia or other inflammation conditions, significantly increase HCs activity. In addition, some mutations in Cx genes associated with human diseases, such as deafness or cataracts, lead to the formation of more active HCs or leaky HCs. In this article we will revise cellular and molecular mechanisms underlying the appearance of leaky HCs, and the consequences of their expression in different cellular systems and animal models, in seeking a common pattern or pathological mechanism of disease.

  7. Gastrointestinal lesions associated with spondyloarthropathies

    Institute of Scientific and Technical Information of China (English)

    Ambrogio Orlando; Sara Renna; Giovanni Perricone; Mario Cottone

    2009-01-01

    Subclinical gut inflammation has been described in up to two-thirds of patients with spondyloarthropathies (SpA). Arthritis represents an extra-intestinal manifestation of several gastrointestinal diseases,including inflammatory bowel disease (IBD), Whipple's disease, Behcet's disease, celiac disease, intestinal bypass surgery, parasitic infections of the gut and pseudomembranous colitis. Moreover about twothirds of nonsteroidal anti-inflammatory drug users demonstrate intestinal inflammation. Arthritis may manifest as a peripheral or axial arthritis. The spondyloarthropathy family consists of the following entities:ankylosing spondylitis, undifferentiated spondyloar thr i t is, react ive ar thr i t is, psor iat i c arthritis, spondyloarthritis associated with IBD,juvenile onset spondyloarthritis. This topic reviews the major gastrointestinal manifestations that can occur in patients with SpA and in nonsteroidal antiinflammatory drugs users.

  8. Molecular Recognition and Ligand Association

    Science.gov (United States)

    Baron, Riccardo; McCammon, J. Andrew

    2013-04-01

    We review recent developments in our understanding of molecular recognition and ligand association, focusing on two major viewpoints: (a) studies that highlight new physical insight into the molecular recognition process and the driving forces determining thermodynamic signatures of binding and (b) recent methodological advances in applications to protein-ligand binding. In particular, we highlight the challenges posed by compensating enthalpic and entropic terms, competing solute and solvent contributions, and the relevance of complex configurational ensembles comprising multiple protein, ligand, and solvent intermediate states. As more complete physics is taken into account, computational approaches increase their ability to complement experimental measurements, by providing a microscopic, dynamic view of ensemble-averaged experimental observables. Physics-based approaches are increasingly expanding their power in pharmacology applications.

  9. Obesity associated noncommunicable disease burden

    Directory of Open Access Journals (Sweden)

    Jyoti Bala Banjare

    2016-01-01

    Full Text Available World is facing rapid transition in health sector for under nutrition and over nutrition. Obesity is a challenging epidemic and increased Body Mass Index (BMI influences on almost all body systems leading to development of non-communicable diseases. Chronic but slow growing non-infectious pathology of body organization give upsurge onset of non-communicable disorders. Obesity related Non-communicable diseases (NCDs leads to millions of deaths all around the world, rapidly becoming economic burden worldwide. Pathophysiology and extend of obesity is responsible for ill effects of health. In obesity Low grade Inflammation and antioxidant disproportion plays vital role in development of NCDs. Effective health education, professional counselling from public health authorities, free health care, and social insurance can be effective in controlling growing non communicable disease globally. The present analysis attempts to study association of obesity with different NCDs in terms of prevalence and underlying mechanisms.

  10. Agranulocytosis associated with dipyrone (metamizol).

    Science.gov (United States)

    Ibáñez, Luisa; Vidal, Xavier; Ballarín, Elena; Laporte, Joan-Ramon

    2005-01-01

    Reported estimates of the risk of agranulocytosis associated with metamizol have varied by several orders of magnitude. We assessed this association in a large database for the surveillance of blood dyscrasias. Since 1980, all laboratory units of haematology in a defined area (3.3-4.1x10(6) inhabitants) contribute to the ascertainment of all cases of agranulocytosis meeting strict diagnostic criteria. These cases of patients with agranulocytosis and sex-, age-, hospital- and date-matched controls were interviewed using a structured questionnaire about previous drug exposures, and relative risks were calculated for several categories of exposure to metamizol. After a total follow-up of 78.73x10(6) person-years, 273 community cases of agranulocytosis had been found--of which 96 were excluded for various reasons and 177 were included in the case-control analysis--and were compared with 586 matched controls. Thirty cases of agranulocytosis (16.9%) and nine controls (1.5%) had been exposed to metamizol during the week before the index day. The adjusted relative risk was 25.8 [95% confidence interval (CI), 8.4-79.1], and the attributable incidence was 0.56 (0.4-0.8) cases per million inhabitants and per year. The risk disappeared after more than 10 days since the last dose of metamizol, and it increased with duration of use. Those with agranulocytosis exposed to metamizol had taken the drug for longer periods than the exposed controls. Compared with the cases recently reported from Sweden, the duration of use of metamizol by our exposed cases was substantially shorter, and the use of concomitant medications potentially causing agranulocytosis was lower. In our milieu, agranulocytosis attributable to metamizol is rare. Geographical disparities in its risk estimate can be partly explained by differences in its patterns of use, in terms of dose, duration and concomitant medications.

  11. Association between Perioperative Parameters and

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    Saba Ghaffary

    2015-10-01

    Full Text Available Background: Postoperative cognitive dysfunction (POCD has been an important complication of cardiac surgery over the years. Neurocognitive dysfunction can affect quality of life and lead to social, functional, emotional, and financial problems in the patient’s life. To reduce POCD, we sought to identify the association between cognitive dysfunction and perioperative factors in patients undergoing cardiac surgery.Methods: One hundred one patients aged between 45 and 75 years undergoing elective cardiac surgery were enrolled in this study. All the surgeries were performed on-pump by the same medical team. A brief Wechsler Memory Test (WMT was administered before surgery, 3 to 5 days after the surgery, and 3 months after discharge. All related perioperative parameters were collected in order to study the effect of these parameters on the postoperative WMT scores and WMT score change.Results: The study population consisted of 101 patients, comprising 14 (13.8% females and 87 (86.2% males aged between 45 and 75 years. In univariate analysis, the baseline WMT score, serum levels of lactate dehydrogenase and T3, cross-clamp time, and preexistence of chronic obstructive pulmonary disease showed significant effects on the postoperative WMT score (p value < 0.05, whereas only the baseline WMT score and chronic obstructive pulmonary disease showed strong effects on the postoperative WMT score in the multiple regression model. In addition, the multiple regression model demonstrated a significant association between the baseline WMT score, serum creatinine level, and nitrate administration and the WMT score change.Conclusion: Our study showed that preexisting chronic obstructive pulmonary disease and preoperative high serum creatinine levels negatively affected cognitive function after surgery. In addition, there was a strong relationship between the patients’ basic cognition and POCD. Preoperative nitrate administration led to a significant improvement

  12. Poor reproducibility of allergic rhinitis SNP associations.

    Directory of Open Access Journals (Sweden)

    Daniel Nilsson

    Full Text Available Replication of reported associations is crucial to the investigation of complex disease. More than 100 SNPs have previously been reported as associated with allergic rhinitis (AR, but few of these have been replicated successfully. To investigate the general reproducibility of reported AR-associations in candidate gene studies, one Swedish (352 AR-cases, 709 controls and one Singapore Chinese population (948 AR-cases, 580 controls were analyzed using 49 AR-associated SNPs. The overall pattern of P-values indicated that very few of the investigated SNPs were associated with AR. Given published odds ratios (ORs most SNPs showed high power to detect an association, but no correlations were found between the ORs of the two study populations or with published ORs. None of the association signals were in common to the two genome-wide association studies published in AR, indicating that the associations represent false positives or have much lower effect-sizes than reported.

  13. Is Pregnancy-Associated Melanoma Associated with Adverse Outcomes?

    Science.gov (United States)

    Jones, Maris S; Lee, Jihey; Stern, Stacey L; Faries, Mark B

    2017-07-01

    Melanoma is the most common malignancy encountered during pregnancy. Conflicting data have led to ongoing confusion regarding pregnancy-associated melanoma (PAM) in the media and among the public. The objective of this study was to better characterize both the clinical presentation of PAM and its prognostic implications. Female patients of reproductive age, with stage 0 to IV cutaneous melanoma, were identified from our prospectively maintained database. Clinical and histopathologic factors were analyzed with appropriate statistical methods. Univariable and then multivariable analysis were used on matched data to compare disease-free survival (DFS), overall survival (OS), and melanoma-specific survival (MSS) for stage 0-III PAMs vs non-PAMs. Kaplan-Meier survival curves were then plotted for OS and MSS and compared using the log-rank test. The clinical presentation of melanoma was similar for PAM and non-PAM patients. There was no significant difference in recurrence between the 2 groups; for PAM patients, 38.5% of patients had recurrence, as compared with 36.6% of non-PAM patients (p = 0.641). For PAM patients, median follow-up was 14.6 years (range 0 to 42.6 years) and 11.1 years (0 to 48.5 years) for the non-PAM patients. No significant differences in DFS, MSS, or OS were identified on univariable or multivariable analysis for PAM vs non-PAM patients in stage 0/I/II and stage III cutaneous melanoma, respectively (p = 0.880 DFS, p = 0.219 OS, and p = 0.670 MSS). We observed no difference in DFS, OS, or MSS between the 2 groups. Pregnant patients should be screened for melanoma in a similar manner to nonpregnant patients and should be counseled that their survival is not adversely affected by their pregnancy. Copyright © 2017 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

  14. Nephrotic Syndrome Associated with Thymoma

    Directory of Open Access Journals (Sweden)

    Sheng-Yen Hsiao

    2014-12-01

    Full Text Available Thymoma is associated with a wide variety of paraneoplastic syndromes such as myasthenia gravis, pure red cell aplasia, and hypogammaglobulinemia. Paraneoplastic glomerulonephritis is a rare clinical presentation of malignancy. This condition often goes undetected as it has no specific clinical symptoms and signs. Approximately 2% of thymoma patients have been reported to have paraneoplastic glomerulonephritis, and the nephrotic syndrome has been shown to be a clinical manifestation of the disorder. We report two cases diagnosed to have thymoma and nephrotic syndrome. Renal biopsy showed that one case had focal segmental glomerulosclerosis, whereas the other had minimal change disease. In case 1, the nephrotic syndrome was diagnosed before thymoma was detected, while in case 2, the symptomatic nephrotic syndrome occurred after thymoma treatment. Because parathymic nephropathy often remains undiagnosed and interferes with treatment, the possibility of the nephrotic syndrome should always be considered throughout the course of thymoma management, particularly in patients who also present with anasarca or hypoalbuminemia. A multidisciplinary approach is needed. Besides, it is to be noted that the nephrotic syndrome may be the initial presentation of thymoma.

  15. Parvovirus B19 Associated Hepatitis

    Science.gov (United States)

    Bihari, Chhagan; Rastogi, Archana; Saxena, Priyanka; Rangegowda, Devraj; Chowdhury, Ashok; Gupta, Nalini; Sarin, Shiv Kumar

    2013-01-01

    Parvovirus B19 infection can present with myriads of clinical diseases and syndromes; liver manifestations and hepatitis are examples of them. Parvovirus B19 hepatitis associated aplastic anemia and its coinfection with other hepatotropic viruses are relatively underrecognized, and there is sufficient evidence in the literature suggesting that B19 infections can cause a spectrum of liver diseases from elevation of transaminases to acute hepatitis to fulminant liver failure and even chronic hepatitis. It can also cause fatal macrophage activation syndrome and fibrosing cholestatic hepatitis. Parvovirus B19 is an erythrovirus that can only be replicate in pronormoblasts and hepatocytes, and other cells which have globosides and glycosphingolipids in their membrane can also be affected by direct virus injury due to nonstructural protein 1 persistence and indirectly by immune mediated injury. The virus infection is suspected in bone marrow aspiration in cases with sudden drop of hemoglobin and onset of transient aplastic anemia in immunosuppressed or immunocompetent patients and is confirmed either by IgM and IgG positive serology, PCR analysis, and in situ hybridization in biopsy specimens or by application of both. There is no specific treatment for parvovirus B19 related liver diseases, but triple therapy regimen may be effective consisting of immunoglobulin, dehydrohydrocortisone, and cyclosporine. PMID:24232179

  16. Microdomains Associated to Lipid Rafts.

    Science.gov (United States)

    Pacheco, Jonathan; Ramírez-Jarquín, Josué O; Vaca, Luis

    2016-01-01

    Store Operated Ca(2+) Entry (SOCE), the main Ca(2+) influx mechanism in non-excitable cells, is implicated in the immune response and has been reported to be affected in several pathologies including cancer. The basic molecular constituents of SOCE are Orai, the pore forming unit, and STIM, a multidomain protein with at least two principal functions: one is to sense the Ca(2+) content inside the lumen of the endoplasmic reticulum(ER) and the second is to activate Orai channels upon depletion of the ER. The link between Ca(2+) depletion inside the ER and Ca(2+) influx from extracellular media is through a direct association of STIM and Orai, but for this to occur, both molecules have to interact and form clusters where ER and plasma membrane (PM) are intimately apposed. In recent years a great number of components have been identified as participants in SOCE regulation, including regions of plasma membrane enriched in cholesterol and sphingolipids, the so called lipid rafts, which recruit a complex platform of specialized microdomains, which cells use to regulate spatiotemporal Ca(2+) signals.

  17. Thyroid Hemiagenesis Associated with Hyperthyroidism

    Directory of Open Access Journals (Sweden)

    Gunay Gurleyik

    2015-01-01

    Full Text Available Thyroid hemiagenesis (TH, very rare congenital anomaly, is generally asymptomatic. We report two cases of TH with hyperthyroidism. Case One. The patient presented with signs and symptoms of thyrotoxicosis. Physical examination revealed asymmetric nodular goitre at right lobe. Biochemical analysis revealed the diagnosis of hyperthyroidism. Ultrasound showed multinodular hypertrophy in the right lobe and absence of the left lobe. Nuclear scan, confirming absence of the left lobe, showed hot nodules in the right one. The diagnosis was toxic multinodular goitre. Case Two. The thyroid was not palpable in this patient presented with signs and symptoms of thyrotoxicosis. Biochemical analysis revealed the diagnosis of autoimmune thyrotoxicosis. Ultrasound showed mild diffuse hyperplasia of the right lobe and agenesis of the left lobe. Nuclear scan, confirming absence of the left lobe, showed increasing diffuse uptake of radiotracer in the right one. The diagnosis was Graves’ disease in this patient. After antithyroid medication, the patients were surgically treated with total excision of the thyroid tissue. TH is sometimes associated with disorders of the thyroid. Hyperthyroidism makes TH cases symptomatic. During evaluation of patients, ultrasound and nuclear scan usually report agenesis of one lobe and establish the diagnosis of TH. The surgical treatment is total removal of hyperactive tissue and total excision of the remaining lobe.

  18. Alagille Syndrome Associated with Xerophthalmia

    Directory of Open Access Journals (Sweden)

    Elad Moisseiev

    2013-12-01

    Full Text Available Purpose: To report the occurrence of xerophthalmia and keratomalacia in a patient with Alagille syndrome. Methods: The patient's record and relevant literature were reviewed. Results: A 3-year-old boy with Alagille syndrome was examined at our institution due to severe bilateral ocular irritation. A corneal ulcer and keratomalacia were found in the right eye and severe dryness with corneal opacification was found in the left eye. He was treated with topical fortified antibiotics in the right eye, followed by amniotic membrane transplantation. Due to his systemic condition, characterized by severe cholestasis and intestinal malabsorption, a suspicion of vitamin A deficiency was raised and was later confirmed in serum analysis. Conclusion: This is the first report of xerophthalmia in a patient with Alagille syndrome. Vitamin A deficiency leading to xerophthalmia is common in developing countries; however, its occurrence in the West is rare, leading to a reduced awareness of this disorder amongst clinicians. Unusual eating habits, intestinal malabsorption and liver disease are possible causes for such a deficiency. The purpose of this case report is to raise awareness to the possibility of vitamin A deficiency in children with keratopathy, especially when associated with these disorders.

  19. Multiplicative contexts in associative memories.

    Science.gov (United States)

    Mizraji, E; Pomi, A; Alvarez, F

    1994-01-01

    A system of networks, consisting of a first net that constructs the Kronecker product between two vectors and then sends it to a second net that sustains a correlation memory, defines a context-dependent associative memory. In the real nervous system of higher mammals, the anatomy of the neural connections surely exhibits a considerable amount of local imprecision superimposed on a regular global layout. In order to evaluate the potentialities of the multiplicative devices to constitute plausible biological models, we analyse the performances of a context-dependent memory when the multiplicative net, responsible of the construction of the Kronecker product, presents an incomplete connectivity. Our study shows that a large dimensional system is able to support a considerable amount of incompleteness in the connectivity without a great deterioration of the memory. We establish a scaling relationship between the degree of incompleteness, the capacity of the memory, and the tolerance threshold to imperfections in the output. We then analyse some performances that show the versatility of this kind of network to represent a variety of functions. These functions include a context-modulated novelty filter, a network that computes logical modalities and an adaptive searching device.

  20. Seven fatalities associated with ethylphenidate.

    Science.gov (United States)

    Maskell, P D; Smith, P R; Cole, R; Hikin, L; Morley, S R

    2016-08-01

    Ethylphenidate is a stimulant novel psychoactive substance that is an analogue of the prescription drug methylphenidate (Ritalin(®)). Methylphenidate is used commonly for the treatment of attention deficit hyperactivity disorder. Due to its stimulant effects ethylphenidate is being abused. There is a single case report of a death associated with ethylphenidate in Germany, and a case series of 19 deaths in the East of Scotland, but otherwise, the contribution of ethylphenidate to death is poorly documented. We report the analytical results of 7 cases (between February 2013 and January 2015) in which ethylphenidate was detected and quantitated with a validated liquid chromatography tandem mass spectrometry method (LC-MS/MS). The individuals (all male) ranged in age from 23 to 49 years (median 25 years). The concentration of ethylphenidate in the cases ranged from 0.026mg/L to 2.18mg/L in unpreserved post-mortem femoral blood. Only one case had ethylphenidate present as a sole drug. All other cases had at least 2 other drug classes present (benzodiazepines, heroin, methadone antipsychotics, other new psychoactive compounds). Ethylphenidate toxicity was the sole contribution to the cause of death in one case. Hanging was the cause of death in 2 cases, with the other 4 cases being reported as having occurred due to mixed drug toxicity. These data will further help with the interpretation of post-mortem ethylphenidate levels.

  1. Lithium-Associated Kidney Microcysts

    Directory of Open Access Journals (Sweden)

    Jennifer Tuazon

    2008-01-01

    Full Text Available Long-term lithium therapy is associated with impairment in concentrating ability and, occasionally, progression to advanced chronic kidney disease from tubulointerstitial nephropathy. Biopsy findings in patients with lithium-induced chronic tubulointerstitial nephropathy include tubular atrophy and interstitial fibrosis interspersed with tubular cysts and dilatations. Recent studies have shown that cysts are seen in 33––62.5% of the patients undergoing lithium therapy. MR imaging is highly capable of defining renal morphological features and has been demonstrated to be superior to US and CT scan for the visualization of small renal cysts. The microcysts are found in both cortex and medulla, particularly in the regions with extensive atrophy and fibrosis, and can be multiple and bilateral. They tend to be sparse and do not normally exceed 1–2 mm in diameter. The renal microcysts in the image here reported are subtle, but consistent with lithium-induced chronic nephropathy. An MRI of the kidneys provides noninvasive evidence that strengthens the diagnosis of lithium-induced nephropathy.

  2. Lithium-associated kidney microcysts.

    Science.gov (United States)

    Tuazon, Jennifer; Casalino, David; Syed, Ehteshamuddin; Batlle, Daniel

    2008-08-31

    Long-term lithium therapy is associated with impairment in concentrating ability and, occasionally, progression to advanced chronic kidney disease from tubulointerstitial nephropathy. Biopsy findings in patients with lithium-induced chronic tubulointerstitial nephropathy include tubular atrophy and interstitial fibrosis interspersed with tubular cysts and dilatations. Recent studies have shown that cysts are seen in 33-62.5% of the patients undergoing lithium therapy. MR imaging is highly capable of defining renal morphological features and has been demonstrated to be superior to US and CT scan for the visualization of small renal cysts. The microcysts are found in both cortex and medulla, particularly in the regions with extensive atrophy and fibrosis, and can be multiple and bilateral. They tend to be sparse and do not normally exceed 1-2 mm in diameter. The renal microcysts in the image here reported are subtle, but consistent with lithium-induced chronic nephropathy. An MRI of the kidneys provides noninvasive evidence that strengthens the diagnosis of lithium-induced nephropathy.

  3. Discoid Meniscus Associated With Achondroplasia.

    Science.gov (United States)

    Hoernschemeyer, Daniel G; Atanda, Alfred; Dean-Davis, Ellen; Gupta, Sumit K

    2016-05-01

    Achondroplasia is the most common skeletal dysplasia. This form of dwarfism is caused by a point mutation in the fibroblast growth factor receptor 3 (FGFR3) gene, leading to inhibition of endochondral ossification for these patients. This results in a normal trunk height but shortened limbs. The discoid meniscus may be an important associated finding to better understand the common complaints of leg pain for these patients. Although the incidence for a discoid meniscus is between 3% and 5% for the general population, it is unknown with achondroplasia. This case series includes 4 patients, with ages ranging from adolescence to early adulthood, with symptoms of knee pain that were not attributable to some of the more common findings seen in this patient population. Typically, patients with achondroplasia who experience knee pain are evaluated for more common and well-known etiologies such as genu varum, ligamentous instability, and neurogenic claudication. However, the authors propose that symptomatic discoid lateral meniscus should be added to the differential diagnosis for lower-extremity pain in the achondroplasia population. A thorough history and physical examination, in combination with magnetic resonance imaging, can aid in making the diagnosis. Treatment with arthroscopic debridement, saucerization of the meniscus, and repair for unstable injuries has yielded good outcomes for this patient population. [Orthopedics. 2016; 39(3):e498-e503.]. Copyright 2016, SLACK Incorporated.

  4. [Isaacs's syndrome and associated diseases].

    Science.gov (United States)

    Watanabe, Osamu

    2013-01-01

    Isaacs' syndrome is an antibody-mediated potassium channel disorder. Clinical symptoms of Isaacs' syndrome are characterized by muscle cramp, slow relaxation following muscle contraction, and hyperhidrosis. Hyperexcitability of the peripheral nerve cause these symptoms, which are relieved by administration of Na channel blockers and immunotherapy.The target channel proteins are voltage-gated potassium channels (VGKCs). The suppression of voltage-gated outward K(+) current by antibodies induces hyperexcitability of the peripheral nerve. Electrophysiological findings show that antibodies may not directly block the kinetics of VGKCs, but may decrease channel density. From the electrophysiological, pharmacologic and immunologic view points, the site of origin of spontaneous discharges is located principally in the distal portion of the motor nerve."VGKC antibodies" are also detected in Morvan syndrome (severe insomnia with neuromyotonia and various autonomic disorders) and in a form of autoimmune limbic encephalitis. Recent studies indicated that the "VGKC antibodies" are mainly directed toward associated proteins (for example LGI-1, CASPR-2) that complex with VGKCs themselves. The "VGKC antibodies" are now usually known as VGKC-complex antibodies. In general, LGI-1 antibodies are most common in limbic encephalitis with SIADH. CASPR-2 antibodies are present in the majority of patients with Morvan syndrome.

  5. [Autoimmune Associated Encephalitis and Dementia].

    Science.gov (United States)

    Watanabe, Osamu

    2016-04-01

    Antibodies against various neural surface antigens induce cognitive impairments. Anti-VGKC (voltage gated potassium channel) complex antibodies are well known as one of the causative autoantibodies. An anti-VGKC antibody was identified as the autoantibody in acquired neuromyotonia (Isaacs' syndrome), which causes muscle cramps and difficulty in opening the palm of the hands. However, this antibody also tests positive in autoimmune limbic encephalitis, which has a subacute progress and causes poor memory or epilepsy attacks. Typical cases have a distinctive adult-onset, frequent, brief dystonic seizure semiology that predominantly affects the arms and ipsilateral face. It has now been termed faciobrachial dystonic seizures. In recent years, the true target antigens of the anti-VGKC antibody of this VGKC limbic encephalitis have been recognized as leucine rich glioma inactivated protein (LGI)-1 and others. These antibodies to amnesia-related LGI-1 in limbic encephalitis neutralize the LGI-1-ADAM22 (an anchor protein) interaction and reduce synaptic AMPA receptors. There have been reports of limbic encephalitis associated with anti-VGKC complex antibodies mimicking Creutzfeldt-Jakob disease (CJD). Less than 2% of the patients with sporadic CJD (sCJD) develop serum anti-VGKC complex antibodies and, when positive, only at low titres. Low titres of these antibodies occur only rarely in suspected patients with sCJD, and when present, should be interpreted with caution.

  6. Association of eumycetoma and schistosomiasis.

    Directory of Open Access Journals (Sweden)

    Jaap J van Hellemond

    Full Text Available Eumycetoma is a morbid chronic granulomatous subcutaneous fungal disease. Despite high environmental exposure to this fungus in certain regions of the world, only few develop eumycetoma for yet unknown reasons. Animal studies suggest that co-infections skewing the immune system to a Th2-type response enhance eumycetoma susceptibility. Since chronic schistosomiasis results in a strong Th2-type response and since endemic areas for eumycetoma and schistosomiasis do regionally overlap, we performed a serological case-control study to identify an association between eumycetoma and schistosomiasis. Compared to endemic controls, eumycetoma patients were significantly more often sero-positive for schistosomiasis (p = 0.03; odds ratio 3.2, 95% CI 1.18-8.46, but not for toxoplasmosis, an infection inducing a Th1-type response (p = 0.6; odds ratio 1.5, 95% CI 0.58-3.83. Here, we show that schistosomiasis is correlated to susceptibility for a fungal disease for the first time.

  7. Association of eumycetoma and schistosomiasis.

    Science.gov (United States)

    van Hellemond, Jaap J; Vonk, Alieke G; de Vogel, Corné; Koelewijn, Rob; Vaessen, Norbert; Fahal, Ahmed H; van Belkum, Alex; van de Sande, Wendy W J

    2013-01-01

    Eumycetoma is a morbid chronic granulomatous subcutaneous fungal disease. Despite high environmental exposure to this fungus in certain regions of the world, only few develop eumycetoma for yet unknown reasons. Animal studies suggest that co-infections skewing the immune system to a Th2-type response enhance eumycetoma susceptibility. Since chronic schistosomiasis results in a strong Th2-type response and since endemic areas for eumycetoma and schistosomiasis do regionally overlap, we performed a serological case-control study to identify an association between eumycetoma and schistosomiasis. Compared to endemic controls, eumycetoma patients were significantly more often sero-positive for schistosomiasis (p = 0.03; odds ratio 3.2, 95% CI 1.18-8.46), but not for toxoplasmosis, an infection inducing a Th1-type response (p = 0.6; odds ratio 1.5, 95% CI 0.58-3.83). Here, we show that schistosomiasis is correlated to susceptibility for a fungal disease for the first time.

  8. Metformin-associated respiratory alkalosis.

    Science.gov (United States)

    Bryant, Sean M; Cumpston, Kirk; Lipsky, Martin S; Patel, Nirali; Leikin, Jerrold B

    2004-01-01

    We present an 84-year-old man with a history of chronic obstructive pulmonary disease, type 2 diabetes, hypertension, glaucoma, and bladder cancer who presented to the emergency department after the police found him disoriented and confused. Metformin therapy began 3 days before, and he denied any overdose or suicidal ideation. Other daily medications included glipizide, fluticasone, prednisone, aspirin, furosemide, insulin, and potassium supplements. In the emergency department, his vital signs were significant for hypertension (168/90), tachycardia (120 bpm), and Kussmaul respirations at 24 breaths per minute. Oxygen saturation was 99% on room air, and a fingerstick glucose was 307 mg/dL. He was disoriented to time and answered questions slowly. Metformin was discontinued, and by day 3, the patient's vital signs and laboratory test results normalized. He has been asymptomatic at subsequent follow-up visits. Metformin-associated lactic acidosis is a well-known phenomenon. Respiratory alkalosis may be an early adverse event induced by metformin prior to the development of lactic acidosis.

  9. Association studies in consanguineous populations

    Energy Technology Data Exchange (ETDEWEB)

    Genin, E.; Clerget-Darpous, F. [Institut National d`Etudes Demographiques, Paris (France)

    1996-04-01

    To study the genetic determinism of multifactorial diseases in large panmictic populations, a strategy consists in looking for an association with markers closely linked to candidate genes. A distribution of marker genotypes different in patients and controls may indicate that the candidate gene is involved in the disease. In panmictic populations, the power to detect the role of a candidate gene depends on the gametic disequilibrium with the marker locus. In consanguineous populations, we show that it depends on the inbreeding coefficient F as well. Inbreeding increases the power to detect the role of a recessive or quasi-recessive disease-susceptibility factor. The gain in power turns out to be greater for small values of the gametic disequilibrium. Moreover, even in the absence of gametic disequilibrium, the presence of inbreeding may allow to detect the role of a recessive factor. Ignoring inbreeding when it exists may lead to reject falsely a recessive model if the mode of inheritance is inferred on the distribution of genotypes among patients. 5 refs., 6 figs., 1 tab.

  10. Rethinking actions: implementation and association.

    Science.gov (United States)

    Quandt, Lorna C; Chatterjee, Anjan

    2015-01-01

    Action processing allows us to move through and interact with the world, as well as understand the movements performed by other people. In recent years, there has been increasing interest in the semantics of actions as differentiated from the semantics of objects. However, as the understanding of action semantics has evolved, it is evident that the existing literature conflates two senses of the word 'action'-one that stems from studies of tool use and the other from event representation. In this paper, we suggest that this issue can be clarified by closely examining differences in how the human parietal and temporal cortices of the brain process action-related stimuli. By contrasting the posterior parietal cortex to the posterolateral temporal cortex, we characterize two complementary action systems in the human brain, each with its own specialization of function. We suggest that these two systems be referred to as the parietal Action Implementation System, and the posterolateral temporal Action Association System. While the frontoparietal system is concerned primarily with how we perform actions, and simulate others' actions, the temporal action system is more involved with processing actions from a third-person, conceptual standpoint. Recent work in cognitive neuroscience of perception and language, as well as the neuroanatomical organization of these brain regions support this distinction. We will discuss the implications of this work for cognition-, language-, and neuroscience-based action research. © 2015 Wiley Periodicals, Inc.

  11. Nelarabine Associated Myotoxicity and Rhabdomyolysis

    Directory of Open Access Journals (Sweden)

    Mahnur Haider

    2015-01-01

    Full Text Available Nelarabine (ara-G; Arranon; compound 506U78 is an antineoplastic purine analog used for the treatment of refractory or relapsed T-cell acute lymphoblastic leukemia (T-ALL and T-cell lymphoblastic lymphoma (T-LBL. The drug was granted accelerated approval in October 2005 by the US Food and Drug Administration (FDA given the efficacy (induction of complete responses noted in 2 single-arm trials (one in pediatric setting and one in adult patient population. The main spectra of toxicities that have been reported in these clinical trials and subsequent studies are hematological and neurological. Nelarabine induced rhabdomyolysis and increased creatinine phosphokinase (CK; CPK levels apparently have been reported and this side effect has been added as an adverse reaction in the product monograph from the drug company during postmarketing surveillance. However, the true extent and incidence of the myotoxicity from the drug are unclear. In this paper we report a grade IV CK elevation and rhabdomyolysis in a patient with T-ALL treated with nelarabine. Given the reported finding, we examined the literature further for myotoxicity, increased CK, and/or rhabdomyolysis associated with the use of the nelarabine and report our findings.

  12. American Association for Marriage and Family Therapy

    Science.gov (United States)

    ... My Account Find Members Benefits American Association for Marriage and Family Therapy 112 South Alfred Street Alexandria, ... Fax: (703) 838-9805 © 2002 - American Association for Marriage and Family Therapy Terms of Use | Privacy Policy | ...

  13. Types of Healthcare-Associated Infections

    Science.gov (United States)

    ... Infection FAQs about SSIs Catheter-associated Urinary Tract Infection FAQs about CAUTI Ventilator-associated Pneumonia FAQs about VAP Diseases and Organisms Acinetobacter Burkholderia cepacia Clostridium difficile Patients Clinicians FAQs about ...

  14. Characterization of melanoma associated spongiform scleropathy

    DEFF Research Database (Denmark)

    Alyahya, Ghassan Ayish Jabur; Heegaard, Steffen; Prause, J.U.

    2002-01-01

    ophthalmology, melanoma associated spongiform scleropathy (MASS), MASS, malignant uveal melanoma, sclera, ciliary body, choroid, histopathology......ophthalmology, melanoma associated spongiform scleropathy (MASS), MASS, malignant uveal melanoma, sclera, ciliary body, choroid, histopathology...

  15. Muriel Lederman honored as associate professor emeritus

    OpenAIRE

    Dickerson, Susan

    2004-01-01

    Muriel Lederman, of Blacksburg, associate professor of biology in the College of Science at Virginia Tech, was conferred with the title "associate professor emeritus" by the Virginia Tech Board of Visitors during the board's quarterly meeting Monday, Aug. 23.

  16. 7 CFR 1219.58 - Importer associations.

    Science.gov (United States)

    2010-01-01

    ... AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE HASS AVOCADO PROMOTION, RESEARCH, AND INFORMATION Hass Avocado Promotion, Research, and Information Order Budgets, Expenses, and Assessments § 1219.58 Importer associations. (a) An association of avocado importers is eligible to...

  17. 7 CFR 1219.2 - Association.

    Science.gov (United States)

    2010-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE HASS AVOCADO PROMOTION, RESEARCH, AND INFORMATION Hass Avocado Promotion, Research, and Information Order Definitions § 1219.2 Association. Association means an avocado organization established by State statute in a State with...

  18. Posterior scleritis associated with systemic tuberculosis

    Directory of Open Access Journals (Sweden)

    Gupta Amit

    2003-01-01

    Full Text Available Infective isolated posterior scleritis is rare. We report a case of isolated posterior scleritis associated with histopathologically documented systemic tuberculosis, a hitherto unreported association. The patient responded well to a combination of oral corticosteroids with antituberculosis therapy.

  19. Is hidradenitis suppurativa associated with anaemia?

    DEFF Research Database (Denmark)

    Miller, I. M.; Johansen, M E; Mogensen, U. B.

    2016-01-01

    BACKGROUND: Chronic inflammatory diseases may be associated with anaemia of inflammation. Hidradenitis suppurativa is a chronic inflammatory dermatological disease associated with metabolic comorbidities, low quality of life and fatigue. Anaemia may cause fatigue, and it has been hypothesized...

  20. Autoimmune diseases associated with neurofibromatosis type 1.

    Science.gov (United States)

    Nanda, Arti

    2008-01-01

    Associations of autoimmune diseases with neurofibromatosis type 1 have been rarely described. In the present report, we describe two patients of neurofibromatosis type 1 having an association with vitiligo in one, and alopecia areata and autoimmune thyroiditis in another. The associations of neurofibromatosis type 1 with vitiligo, alopecia areata, and autoimmune thyroiditis have not been reported earlier. Whether these associations reflect a causal relationship with neurofibromatosis type 1 or are coincidental needs to be settled.

  1. Idiosyncratic Pancreatitis Associated with Perindopril

    Directory of Open Access Journals (Sweden)

    Giuseppe Famularo

    2005-11-01

    Full Text Available The use of angiotensin-converting enzyme (ACE inhibitors is not associated with an increased risk of acute pancreatitis [1] and, so far, only one case has been linked with the use of perindopril [2]. We report on a second patient with perindopril-induced pancreatitis. A 72-year-old man presented with a 10-day history of nausea, vomiting, and constant pain in the epigastrium which radiated to the sides. Four weeks before admission, perindopril (4 mg/day had been added to the usual regimen of glyburide (5 mg/day, metformin (1 g/day and carvedilol (6.25 mg/day which the patient had been taking for three years for the treatment of diabetes mellitus and moderate hypertension. His previous history was otherwise unremarkable, except for psoriasis; he did not report any acute or chronic pancreatic disease and denied alcohol use, toxic habits or taking any other medications including over-the-counter medications or herbal remedies. Upon admission, the patient was fully alert and oriented, apyrexial and had normal vital parameters; physical examination yielded normal findings apart from a severely tender abdomen with no bowel sounds. Laboratory data showed increased blood amylase (556 IU/L; reference range: 0-115 IU/L and lipase (1,396 IU/L; reference range: 0-190 IU/L levels; electrolytes, hematological variables, cholesterol, triglycerides, liver and renal function tests, and blood gases were normal. The results of serologic tests for the Mycoplasma and Chlamydia species, viral hepatitis, and a wide range of other viral infections were also negative. Abdominal ultrasonography and computed tomography showed a moderately enlarged and edematous pancreas; furthermore, at imaging techniques no alterations such as stones or sludge of the gallbladder and of the common bile duct were detected. A chest X-ray was also normal.

  2. Analyze of Ventilator Associated Pneumonia

    Directory of Open Access Journals (Sweden)

    Aysel Sunnetcioglu

    2014-03-01

    Full Text Available Aim: Ventilator-associated pneumonia (VAP is the infection that is an important cause of morbidity and mortality developed in patients whom the invasive mechanical ventilation (MV were performed in intensive care units (ICU. In this study, the factors of VAP developing in patients whom the mechanical ventilation of ICU performed, antibiotic susceptibility to these factors and determining the risk factors were aimed. Material and Method: Between January 2009 and March 2013, 79 cases, followed with the mechanical ventilation for at least for 48 hours and developed VAP, were retrospectively reviewed at Anesthesiology and Intensive Care Unit of Reanimation at Faculty of Medicine at Yuzuncu Yil University, performing endotracheal intubation. The cases were evaluated in terms of microorganisms, antibiotic susceptibility and risk factors. Results: The rate of our VAP speed was calculated to be 19.68 on the day of 1000 ventilator. While a single microorganism could be isolated in 81.1% of the 74 VAP cases whose the active pathogen could be isolated, two or more than two microorganisms were isolated in 18.9% of them.While 83 of the strains (90.2% were gram-negative bacteria, 7 of them (7.6% were gram-positive bacteria. Acinetobacter spp. (40.2% was most commonly isolated as a gram-negative factor, but methicillin-resistant S. aureus (4.3% was isolated as a gram-positive factor. It was determined that the isolated factors in VAP cases were significantly resistant to the broad-spectrum antibiotics. Discussion: As a result, in patients with high-risk factors for the development of VAP, early and appropriate empirical antibiotic treatment should be started according to the results of the sensitivity of the unit and for the multi-drug-resistant microorganisms with common and high mortality.

  3. Evolutionary specializations of human association cortex

    NARCIS (Netherlands)

    Mars, R.B.; Passingham, R.E.; Neubert, F.X.; Verhagen, L.; Sallet, J.

    2017-01-01

    Is the human brain a big ape brain? We argue that the human association cortex is larger than would be expected for an equivalent ape brain, suggesting human association cortex is a unique adaptation. The internal organization of the human association cortex shows modifications of the ape plan in

  4. Neural associative memories and sparse coding.

    Science.gov (United States)

    Palm, Günther

    2013-01-01

    The theoretical, practical and technical development of neural associative memories during the last 40 years is described. The importance of sparse coding of associative memory patterns is pointed out. The use of associative memory networks for large scale brain modeling is also mentioned.

  5. Efficient Mining of Intertransaction Association Rules

    NARCIS (Netherlands)

    Tung, A.K.H.; Lu, H.J.; Han, J.W.; Feng, L.

    2003-01-01

    Most of the previous studies on mining association rules are on mining intratransaction associations, i.e., the associations among items within the same transaction where the notion of the transaction could be the items bought by the same customer, the events happened on the same day, etc. In this s

  6. Pigmentation associated histopathological variations in sympathetic ophthalmia.

    Science.gov (United States)

    Marak, G E; Ikui, H

    1980-01-01

    The severity of inflammation in sympathetic ophthalmia is related to the degree of pigmentation, and the granulomatous response seems to be related to pigmentation. Eosinophilia is also associated with pigmentation, but this association appears to be fortuitous and is a result of the association of eosinophilia with severity of the inflammation. PMID:7387955

  7. Histopathology of mucosa-associated lymphoid tissue

    NARCIS (Netherlands)

    Kuper, C.F.

    2006-01-01

    Mucosa-associated lymphoid tissue (MALT) is a generalized term incorporating a disseminated collection of lymphoid tissues in multiple sites throughout the body. MALT sites that have been/are primarily studied include bronchus-associated lymphoid tissue (BALT), gut-associated lymphoid tissue (GALT),

  8. Pulmonary carcinoid tumor associated with nephrotic syndrome.

    Science.gov (United States)

    DePace, N L; Elquezabal, A; Hardenburg, H C

    1980-04-01

    A patient with carcinoid tumor of the lung associated with nephrotic syndrome was treated. Excision of the tumor resulted in remission of marked proteinuria, hypoalbuminemia, and edema. A review of the literature disclosed many neoplasms associated with the nephrotic syndrome; however, no association of the nephrotic syndrome and a carcinoid tumor of the lung has previously been reported, to our knowledge.

  9. 7 CFR 1230.25 - State association.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false State association. 1230.25 Section 1230.25... association. State association means the single organization of producers in a State that is organized under the laws of that State and is recognized by the chief executive officer of such State as...

  10. 27 CFR 10.22 - Employee associations.

    Science.gov (United States)

    2010-04-01

    ..., DEPARTMENT OF THE TREASURY LIQUORS COMMERCIAL BRIBERY Commercial Bribery § 10.22 Employee associations. Gifts... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Employee associations. 10... employee associations are considered the same as bonuses, premiums, compensation, or other things of...

  11. The mathematics behind the property of associativity

    OpenAIRE

    Marichal, Jean-Luc; Teheux, Bruno

    2016-01-01

    The well-known equation of associativity for binary operations may be naturally generalized to variadic operations. In this talk, we illustrate different approaches that can be considered to study this extension of associativity, as well as some of its generalizations and variants, including barycentric associativity and preassociativity.

  12. Quadrivalent Human Papillomavirus recombinant vaccine associated lipoatrophy.

    Science.gov (United States)

    Ojaimi, Samar; Buttery, Jim P; Korman, Tony M

    2009-08-06

    Involutional lipoatrophy, a loss of subcutaneous fat, may be idiopathic, associated with inflammatory skin conditions, or trauma, and has also been reported following injections of medications including insulin, corticosteroids and penicillin. There have also been reports in association with Diptheria Pertussis Tetanus (DPT) vaccine. We report on two cases of lipoatrophy associated with the new Quadrivalent Human Papillomavirus (HPV) recombinant vaccine (Gardasil).

  13. Associative learning for a robot intelligence

    CERN Document Server

    Andreae, John H

    1998-01-01

    The explanation of brain functioning in terms of the association of ideas has been popular since the 17th century. Recently, however, the process of association has been dismissed as computationally inadequate by prominent cognitive scientists. In this book, a sharper definition of the term "association" is used to revive the process by showing that associative learning can indeed be computationally powerful. Within an appropriate organization, associative learning can be embodied in a robot to realize a human-like intelligence, which sets its own goals, exhibits unique unformalizable behaviou

  14. A Statistical Model of Skewed Associativity

    OpenAIRE

    Michaud, Pierre

    2002-01-01

    This paper presents a statistical model of set-associativity, victim caching and skewed-associativity, with an emphasis on skewed-associativity. We show that set-associativity is not efficient when the working-set size is close to the cache size. We refer to this as the unit working-set problem. We show that victim-caching is not a practical solution to the unit working-se- t problem either, although victim caching emulates full associativity for working-sets much larger than the victim buffe...

  15. MYOSITIS ASSOCIATED WITH MALIGNANT TUMORS

    Directory of Open Access Journals (Sweden)

    O. A. Antelava

    2016-01-01

    Full Text Available Idiopathic inflammatory myopathies (IIM are a heterogeneous group of acquired systemic diseases mainly involving skeletal muscles. The main representatives of IIM are polymyositis (PM and dermatomyositis (DM. Epidemiological surveys demonstrate that there is a relationship between PM/DM and malignant neoplasms (MNs, the detection risk of which is higher than that in the population of respective age groups. The rate of MNs in PM/DM ranges from 9 to 50%. The relationship to MNs is described in each subtype of IIM; however, these are most common in DM. The patients suffering from PM/DM associated with MNs have a worse prognosis than those without MNs. The early detection of MNs could improve the prognosis in these patients. The investigations published identify demographic, clinical, and laboratory factors increasing MN detection risks in patients with PM/DM. Just the same, they all cover small patient groups; the findings are heterogeneous and not well convincing, which calls for a further larger-scale study of this problem.Objective: to reveal and identify the specific features of paraneoplastic myositis (PnM.Subjects and methods. The investigation included 320 patients with a valid diagnosis of IIM, who had been followed up in the period of 1996 to 2016. The patients underwent laboratory tests, manual proximal muscle strength testing using a 10-point scale and electromyographic examination with needle electrodes.Results and discussion. PnM was detected in 32 (10% of the 320 patients with IIM. Among the patients with PnM, there were 6 (19% men and 26 (81% women. The mean age at the onset of PnM was 55.4 years. PnM manifested with characteristic musculocutaneous syndrome in 19 (59% patients; 18 (41% of them were found to have MNs within the first year after disease onset. The manifestation of MNs was preliminary to the picture of PM/DM in 13 (41% patients. The most commonly detected conditions were ovarian cancer (37.5%, MNs of the lung and breast

  16. Comparison of associative recognition versus source recognition.

    Science.gov (United States)

    Park, Heekyeong; Abellanoza, Cheryl; Schaeffer, James D

    2014-10-03

    The importance of the medial temporal lobe (MTL) for memory of arbitrary associations has been well established. However, the contribution of the MTL in concurrent retrieval of different classes of associations remains unclear. The present fMRI study investigated neural correlates of concurrent retrieval of associative and source memories. Participants studied a list of object pairs with two study tasks and judged the status and context of the pair during test. Associative retrieval was supported by neural activity in bilateral prefrontal cortex and left ventral occipito-temporal cortex, while source recognition was linked to activity in the right caudate. Both the hippocampus and MTL cortex showed retrieval activity for associative and source memory. Importantly, greater brain activity for successful associative recognition accompanied with successful source recognition was evident in left perirhinal and anterior hippocampal regions. These results indicate that the MTL is critical in the retrieval of different classes of associations.

  17. Pemphigus vulgaris-associated interstitial lung disease.

    Science.gov (United States)

    Bai, Yi-Xiu; Chu, Jin-Gang; Xiao, Ting; Chen, Hong-Duo

    2016-07-01

    Autoimmune bullous diseases (AIBDs)-associated interstitial lung disease (ILD) is extremely rare. Pemphigus vulgaris (PV) is an intraepidermal autoimmune blistering disease caused by circulating autoantibodies against desmoglein. To date, PV-associated ILD has rarely been reported in English literature. We report a rare association of PV and ILD. A 53-year-old Chinese female with PV for 8 months developed ILD after a relapse of PV for 2 months due to discontinuation of oral prednisone by herself. She was successfully treated by systemic methylprednisolone. Taken previously reported bullous pemphigoid-associated ILD and linear IgA/IgG bullous dermatosis-associated ILD together, in general, AIBDs-associated ILD occurs when AIBDs relapse or are not controlled, responds well to systemic corticosteroids, and has a relatively better prognosis when compared with rheumatoid arthritis- or dermatomyositis-associated ILD.

  18. 12 CFR 615.5172 - Production credit association and agricultural credit association investment in farmers' notes...

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Production credit association and agricultural credit association investment in farmers' notes given to cooperatives and dealers. 615.5172 Section 615....5172 Production credit association and agricultural credit association investment in farmers'...

  19. Priming in a free association task as a function of association directionality

    NARCIS (Netherlands)

    R. Zeelenberg; R.M. Shiffrin; J.G.W. Raaijmakers

    1999-01-01

    Two experiments investigated priming in free association, a conceptual implicit memory task. The stimuli consisted of bidirectionally associated word pairs (e.g., BEACH-SAND) and unidirectionally associated word pairs that have no association from the target response back to the stimulus cue (e.g.,

  20. Image segmentation using association rule features.

    Science.gov (United States)

    Rushing, John A; Ranganath, Heggere; Hinke, Thomas H; Graves, Sara J

    2002-01-01

    A new type of texture feature based on association rules is described. Association rules have been used in applications such as market basket analysis to capture relationships present among items in large data sets. It is shown that association rules can be adapted to capture frequently occurring local structures in images. The frequency of occurrence of these structures can be used to characterize texture. Methods for segmentation of textured images based on association rule features are described. Simulation results using images consisting of man made and natural textures show that association rule features perform well compared to other widely used texture features. Association rule features are used to detect cumulus cloud fields in GOES satellite images and are found to achieve higher accuracy than other statistical texture features for this problem.

  1. An Improved Technique for Ranking Semantic Associations

    Directory of Open Access Journals (Sweden)

    S Narayana

    2013-10-01

    Full Text Available The primary focus of the search techniques in the first generation of the Web is accessing relevant documents from the Web. Though it satisfies user requirements, but it is insufficient as the user sometimes wishes to access actionable information involving complex relationships between two given entities. Finding such complex relationships (also known as semantic associations is especially useful in applications such as National Security, Pharmacy, Business Intelligence etc. Therefore the next frontier is discovering relevant semantic associations between two entities present in large semantic metadata repositories. Given two entities, there exist a huge number of semantic associations between two entities. Hence ranking of these associations is required in order to find more relevant associations. For this Aleman Meza et al. proposed a method involving six metrics viz. context, subsumption, rarity, popularity, association length and trust. To compute the overall rank of the associations this method computes context, subsumption, rarity and popularity values for each component of the association and for all the associations. However it is obvious that, many components appears repeatedly in many associations therefore it is not necessary to compute context, subsumption, rarity, popularity, and trust values of the components every time for each association rather the previously computed values may be used while computing the overall rank of the associations. This paper proposes a method to reuse the previously computed values using a hash data structure thus reduce the execution time. To demonstrate the effectiveness of the proposed method, experiments were conducted on SWETO ontology. Results show that the proposed method is more efficient than the other existing methods.

  2. Alpha-beta bidirectional associative memories

    OpenAIRE

    María Elena Acevedo Mosqueda; Cornelio Yáñez Márquez

    2006-01-01

    Most models of Bidirectional associative memories intend to achieve that all trained pattern correspond to stable states; however, this has not been possible. Also, none of the former models has been able to recall all the trained patterns. In this work we introduce a new model of bidirectional associative memory which is not iterative and has no stability problems. It is based on the Alpha-Beta associative memories. This model allows perfect recall of all trained patterns, with no ambiguity ...

  3. Reliability analysis of an associated system

    Institute of Scientific and Technical Information of China (English)

    陈长杰; 魏一鸣; 蔡嗣经

    2002-01-01

    Based on engineering reliability of large complex system and distinct characteristic of soft system, some new conception and theory on the medium elements and the associated system are created. At the same time, the reliability logic model of associated system is provided. In this paper, through the field investigation of the trial operation, the engineering reliability of the paste fill system in No.2 mine of Jinchuan Non-ferrous Metallic Corporation is analyzed by using the theory of associated system.

  4. Multi-Valued Associative Memory Neural Network

    Institute of Scientific and Technical Information of China (English)

    修春波; 刘向东; 张宇河

    2003-01-01

    A novel learning method for multi-valued associative memory network is introduced, which is based on Hebb rule, but utilizes more information. According to the current probe vector, the connection weights matrix could be chosen dynamically. Double-valued and multi-valued associative memory are all realized in our simulation experiment. The experimental results show that the method could enhance the associative success rate.

  5. Association Rules Applied to Intrusion Detection

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    We discuss the basic intrusion detection techniques, and focus on how to apply association rules to intrusion detection. Begin with analyzing some close relations between user's behaviors, we discuss the mining algorithm of association rules and apply to detect anomaly in IDS. Moreover, according to the characteristic of intrusion detection, we optimize the mining algorithm of association rules, and use fuzzy logic to improve the system performance.

  6. Cryopyrin-Associated Autoinflammatory Syndromes (CAPS) - Juvenile

    Science.gov (United States)

    ... Cryopyrin-Associated Autoinflammatory Syndrome (CAPS) (Juvenile) Dermatomyositis (Juvenile) Familial Mediterranean Fever (Juvenile) Fibromyalgia Giant Cell Arteritis Glucocorticoid-induced Osteoperosis ...

  7. Query Through Heterogeneous Ontologies Using Association Matrix

    Institute of Scientific and Technical Information of China (English)

    KANG Da-zhou; XU Bao-wen; LU Jian-jiang; WANG Peng; LI Yan-hui

    2004-01-01

    This paper introduces the definition and calculation of the association matrix between ontologies.It uses the association matrix to describe the relations between concepts in different ontologies and uses concept vectors to represent queries; then computes the vectors with the association matrix in order to rewrite queries.This paper proposes a simple method of querying through heterogeneous Ontology using association matrix.This method is based on the correctness of approximate information filtering theory; and it is simple to be implemented and expected to run quite fast.

  8. Publication manual of the American Psychological Association

    National Research Council Canada - National Science Library

    2010-01-01

    With millions of copies sold, the Publication Manual of the American Psychological Association is the style manual of choice for writers, editors, students, educators, and professionals in psychology...

  9. Associated factors to academic performance in adult

    Directory of Open Access Journals (Sweden)

    Mawency Vergel-Ortega

    2016-08-01

    Full Text Available The article has the objective identify the associated factors to academic performance of adult students in mathematics and statistics modules. Was realized a study quantitative correlational in a sample of 80 students with age over 30 years old. A group of institutional aspects, social-demographics, psychosocials and pedagogic factors were used as independent variable. Results indicate that style of learning associated with type of intelligence, deficit conscience associated to abstraction capability and family motivation predicts the higher levels of performance, constituting explicative variables. Conclusion: type and style of learning, type of intelligence, motivation, conscience of deficit are associated factors to performance in adults.

  10. Association Rule Mining and Its Application

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Several algorithms in data mining technique have been studied recently, among which association is one of the most important techniques. In this paper, we introduce theory of association rule in data mining, and analyze the characteristics of postal EMS service. We create a data warehouse model for EMS services and give the procedure of applying association rule mining based on it. In the end, we give an example of the whole mining procedure. This EMS-Data warehouse model and association rule mining technique have been applied in a practical Postal CRM System.

  11. Breast fibromatosis associated with breast implants.

    Science.gov (United States)

    Seo, Yoon Nae; Park, Young Mi; Yoon, Hye Kyoung; Lee, Sun Joo; Choo, Hye Jung; Ryu, Ji Hwa

    2015-09-01

    Fibromatosis refers to an extra-abdominal desmoid tumor or aggressive fibromatosis. Breast fibromatosis can develop in association with the capsule around a breast implant, although reports of cases of fibromatosis associated with breast implants are rare. As the demand for breast augmentation has increased, it is important to understand the diseases associated with breast implants. In the present report, we describe a case of breast fibromatosis that developed adjacent to a breast implant and demonstrated a relatively well-defined border even though it invaded the surrounding structures. We also explore the specific imaging features for diagnosing breast fibromatosis in association with implants by reviewing previous literature.

  12. Factors associated with adolescent pregnancies among secondary ...

    African Journals Online (AJOL)

    Factors associated with adolescent pregnancies among secondary school students. a study from Tanga-Tanzania. ... PROMOTING ACCESS TO AFRICAN RESEARCH. AFRICAN JOURNALS ... Dar Es Salaam Medical Students' Journal.

  13. Semantic associative relations and conceptual processing.

    Science.gov (United States)

    Di Giacomo, Dina; De Federicis, Lucia Serenella; Pistelli, Manuela; Fiorenzi, Daniela; Passafiume, Domenico

    2012-02-01

    We analysed the organisation of semantic network using associative mechanisms between different types of information and studied the progression of the use of these associative relations during development. We aimed to verify the linkage of concepts with the use of semantic associative relations. The goal of this study was to analyse the cognitive ability to use associative relations between various items when describing old and/or new concepts. We examined the performance of 100 subjects between the ages of 4 and 7 years on an experimental task using five associative relations based on verbal encoding. The results showed that children are able to use the five semantic associative relations at age 4, but performance with each of the different associative relations improves at different times during development. Functional and part/whole relations develop at an early age, whereas the superordinate relations develop later. Our study clarified the characteristics of the progression of semantic associations during development as well as the roles that associative relations play in the structure and improvement of the semantic store.

  14. Helicobacter heilmannii-associated Gastritis: Clinicopathologic Findings and Comparison with Helicobacter pylori-associated Gastritis

    Science.gov (United States)

    Kwak, Ji Eun; Chang, Sun Hee; Kim, Hanseong; Chi, Je G.; Kim, Kyung-Ah; Yang, Jeon Ho; Lee, June Sung; Moon, Young-Soo; Kim, Kyoung-Mee

    2007-01-01

    The aims of this study were to evaluate the clinicopathologic features of Helicobacter heilmannii-associated gastritis and to compare H. heilmannii-associated gastritis with H. pylori-associated gastritis. We reviewed 5,985 consecutive gastric biopsy specimens. All cases of chronic gastritis with Helicobacter infection were evaluated with the Updated Sydney System, and the grades of all gastritis variables were compared between H. heilmannii-associated gastritis and H. pylori-associated gastritis groups. There were 10 cases of H. heilmannii-associated gastritis (0.17%) and 3,285 cases of H. pylori-associated gastritis (54.9%). The organisms were superficially located within the mucous layer without adhesion to epithelial cells. Interestingly, in one case many intracytoplasmic H. heilmannii organisms were observed in parietal cells with cell damage. A case of low-grade mucosa-associated lymphoid tissue (MALT) lymphoma concomitant with H. heilmannii infection was detected. Compared to H. pylori-associated gastritis, H. heilmannii-associated gastritis showed less severe neutrophilic activity (pgastritis devoid of erosion or ulcer (p=0.0309). In conclusion, we present the detailed clinicopathologic findings of H. heilmannii-associated gastritis compared to H. pylori-associated gastritis. H. heilmannii-associated gastritis is uncommon and milder than H. pylori-associated gastritis, however it may be noteworthy with respect to the development of MALT lymphoma. PMID:17297253

  15. FILIAL IMPRINTING AND ASSOCIATIVE LEARNING - SIMILAR MECHANISMS

    NARCIS (Netherlands)

    van Kampen, Hendrik

    1993-01-01

    This paper reviews a series of experiments designed to investigate whether features characteristic for associative learning are also true of filial imprinting. Phenomena resembling blocking and overshadowing in associative learning may occur during imprinting on two different objects, but it is

  16. Associations between phenotypes of preeclampsia and thrombophilia.

    Science.gov (United States)

    Berks, Durk; Duvekot, Johannes J; Basalan, Hillal; De Maat, Moniek P M; Steegers, Eric A P; Visser, Willy

    2015-11-01

    Preeclampsia complicates 2-8% of all pregnancies. Studies on the association of preeclampsia with thrombophilia are conflicting. Clinical heterogeneity of the disease may be one of the explanations. The present study addresses the question whether different phenotypes of preeclampsia are associated with thrombophilia factors. Study design We planned a retrospective cohort study. From 1985 until 2010 women with preeclampsia were offered postpartum screening for the following thrombophilia factors: anti-phospholipid antibodies, APC-resistance, protein C deficiency and protein S deficiency, hyperhomocysteineamia, factor V Leiden and Prothrombin gene mutation. Hospital records were used to obtain information on phenotypes of the preeclampsia and placental histology. We identified 844 women with singleton pregnancies who were screened for thrombophilia factors. HELLP complicated 49% of pregnancies; Fetal growth restriction complicated 61% of pregnancies. Early delivery (preeclampsia was associated with protein S deficiency (p=0.01). Fetal growth restriction was associated with anti-phospholipid antibodies (ppreeclampsia was associated with anti-phospholipid antibodies (p=0.01). Extensive placental infarction (>10%) was associated with anti-phospholipid antibodies (ppreeclampsia, especially if complicated by fetal growth restriction, are associated with anti-phospholipid antibodies. Other phenotypes of preeclampsia, especially HELLP syndrome, were not associated with thrombophilia. We advise only to test for anti-phospholipid antibodies after early onset preeclampsia, especially if complicated by fetal growth restriction. We suggest enough evidence is presented to justify no further studies are needed. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  17. The association between multiple sclerosis and uveitis

    DEFF Research Database (Denmark)

    Olsen, Tine Gadegaard; Frederiksen, Jette

    2017-01-01

    The association between multiple sclerosis (MS) and uveitis has been questioned. Nerve tissue and eye tissue develop from the same embryonic cells; thus, MS and uveitis could be etiologically associated. In published studies, the prevalence of MS in patients with uveitis differe from 0.7% to 30...

  18. Multiple pilomatricomas in association with trisomy 9.

    Science.gov (United States)

    Blaya, Bruno; Gonzalez-Hermosa, Rosario; Gardeazabal, Jesus; Diaz-Perez, Jose-Luis

    2009-01-01

    Multiple appearance of pilomatricoma is a rare phenomenon that has been associated with some diseases like Gardner syndrome, myotonic dystrophy, and Rubinstein-Taybi syndrome. We present a case of association of multiple pilomatricoma and trisomy 9, which represents the third published in literature. As a result of the small prevalence of these two entities, we believe they could be related.

  19. Hierarchical document categorization using associative networks

    NARCIS (Netherlands)

    Bloom, Niels; Theune, Mariet; de Jong, Franciska M.G.; Klement, E.P.; Borutzky, W.; Fahringer, T.; Hamza, M.H.; Uskov, V.

    Associative networks are a connectionist language model with the ability to handle dynamic data. We used two associative networks to categorize random sets of related Wikipedia articles with only their raw text as input. We then compared the resulting categorization to a gold standard: the manual

  20. Hearing impairment associated with oral terbinafine use

    NARCIS (Netherlands)

    Scholl, Joep; Van Grootheest, Kees; Van Puijenbroek, Eugene

    2012-01-01

    Background: The Netherlands Pharmacovigilance Centre Lareb received six reports of hearing impairment in association with oral terbinafine use. This study describes these cases and provides support for this association from the Lareb database of spontaneous ADR reporting and from Vigibase, the adver

  1. Shift-invariant optical associative memories

    Energy Technology Data Exchange (ETDEWEB)

    Psaltis, D.; Hong, J.

    1987-01-01

    Shift invariance in the context of associative memories is discussed. Two optical systems that exhibit shift invariance are described in detail with attention given to the analysis of storage capacities. It is shown that full shift invariance cannot be achieved with systems that employ only linear interconnections to store the associations.

  2. Are Musical Instrument Gender Associations Changing?

    Science.gov (United States)

    Abeles, Hal

    2009-01-01

    The researcher sought to examine gender associations across three decades to determine if changes in the sex stereotyping of musical instruments has occurred. First, the study examined the paired comparison gender-instrument rankings of 180 college students. The results confirmed a reduction of instrument gender associations reported in the 1990s.…

  3. FILIAL IMPRINTING AND ASSOCIATIVE LEARNING - SIMILAR MECHANISMS

    NARCIS (Netherlands)

    van Kampen, Hendrik

    1993-01-01

    This paper reviews a series of experiments designed to investigate whether features characteristic for associative learning are also true of filial imprinting. Phenomena resembling blocking and overshadowing in associative learning may occur during imprinting on two different objects, but it is unli

  4. Implicit Measures of Association in Psychopathology Research

    NARCIS (Netherlands)

    Roefs, Anne; Huijding, Jorg; Smulders, Fren T. Y.; MacLeod, Colin M.; de Jong, Peter J.; Wiers, Reinout W.; Jansen, Anita T. M.

    2011-01-01

    Studies obtaining implicit measures of associations in Diagnostic and Statistical Manual of Mental Disorders (4th ed., Text Revision; American Psychiatric Association, 2000) Axis 1 psychopathology are organized into three categories: (a) studies comparing groups having a disorder with controls, (b)

  5. Implicit Measures of Association in Psychopathology Research

    Science.gov (United States)

    Roefs, Anne; Huijding, Jorg; Smulders, Fren T. Y.; MacLeod, Colin M.; de Jong, Peter J.; Wiers, Reinout W.; Jansen, Anita T. M.

    2011-01-01

    Validity;Measures (Individuals);Studies obtaining implicit measures of associations in "Diagnostic and Statistical Manual of Mental Disorders" (4th ed., Text Revision; American Psychiatric Association, 2000) Axis I psychopathology are organized into three categories: (a) studies comparing groups having a disorder with controls, (b) experimental…

  6. Implicit measures of association in psychopathology research

    NARCIS (Netherlands)

    Roefs, A.; Huijding, J.; Smulders, F.T.Y.; MacLeod, C.M.; de Jong, P.J.; Wiers, R.W.; Jansen, A.T.M.

    2011-01-01

    Studies obtaining implicit measures of associations in Diagnostic and Statistical Manual of Mental Disorders (4th ed., Text Revision; American Psychiatric Association, 2000) Axis I psychopathology are organized into three categories: (a) studies comparing groups having a disorder with controls, (b)

  7. Associations at La Chaux-de-Fonds

    Science.gov (United States)

    Coenen-Hunter, Josette

    1975-01-01

    Associations are media of both social participation and cultural life, playing an important part in community development. The scientific team of La Chaux-de-Fonds, Switzerland, therefore focused its study on the characteristics of associations' memberships, their activities and their operational problems. (Author/RK)

  8. Colon cancer associated transcripts in human cancers.

    Science.gov (United States)

    Chen, Yincong; Xie, Haibiao; Gao, Qunjun; Zhan, Hengji; Xiao, Huizhong; Zou, Yifan; Zhang, Fuyou; Liu, Yuchen; Li, Jianfa

    2017-08-02

    Long non-coding RNAs serve as important regulators in complicated cellular activities, including cell differentiation, proliferation and death. Dysregulation of long non-coding RNAs occurs in the formation and progression of cancers. The family of colon cancer associated transcripts, long non-coding RNAs colon cancer associated transcript-1 and colon cancer associated transcript-2 are known as oncogenes involved in various cancers. Colon cancer associated transcript-1 is a novel lncRNA located in 8q24.2, and colon cancer associated transcript-2 maps to the 8q24.21 region encompassing rs6983267. Colon cancer associated transcripts have close associations with clinical characteristics, such as lymph node metastasis, high TNM stage and short overall survival. Knockdown of them can reverse the malignant phenotypes of cancer cells, including proliferation, migration, invasion and apoptosis. Moreover, they can increase the expression level of c-MYC and oncogenic microRNAs via activating a series of complex mechanisms. In brief, the family of colon cancer associated transcripts may serve as potential biomarkers or therapeutic targets for human cancers. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  9. Sepsis associated encephalopathy (SAE): a review.

    Science.gov (United States)

    Green, Rebecca; Scott, L Keith; Minagar, Alireza; Conrad, Steven

    2004-05-01

    Sepsis associated encephalopathy (SAE) is a poorly understood condition that is associated with severe sepsis and appears to have a negative influence on survival. The incidence of encephalopathy secondary to sepsis is unknown. Amino acid derangements, blood-brain barrier disruption, abnormal neurotransmitters, and direct CNS effect are possible causes of septic encephalopathy. Research has not defined the pathogenesis of SAE.

  10. Pancreatitis associated with the use of itraconazole

    NARCIS (Netherlands)

    Passier, J L M; van Puijenbroek, E P; Jonkers, G J P M; van Grootheest, A C

    2010-01-01

    BACKGROUND: We call attention to the assumed association between itraconazole and pancreatitis by presentation of four Dutch case reports. METHODS AND RESULTS: The Netherlands Pharmacovigilance Centre Lareb received four reports of pancreatitis associated with the use of itraconazole, all reported b

  11. Staff Association Handbook, 1974-75.

    Science.gov (United States)

    Montgomery Coll. Staff Association, Takoma Park, MD.

    This handbook provides a list of Staff Senate and Committee members of the Staff Association of Montgomery College, a copy of the bylaws of the association, and sections of the college's "Policies and Procedures Manual" that affect staff employees. These sections of the manual pertain to: Administrative and Staff Communication;…

  12. 12 CFR 615.5142 - Association investments.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Association investments. 615.5142 Section 615.5142 Banks and Banking FARM CREDIT ADMINISTRATION FARM CREDIT SYSTEM FUNDING AND FISCAL AFFAIRS, LOAN POLICIES AND OPERATIONS, AND FUNDING OPERATIONS Investment Management § 615.5142 Association...

  13. Sequential association rules in atonal music

    NARCIS (Netherlands)

    A. Honingh; T. Weyde; D. Conklin

    2009-01-01

    This paper describes a preliminary study on the structure of atonal music. In the same way as sequential association rules of chords can be found in tonal music, sequential association rules of pitch class set categories can be found in atonal music. It has been noted before that certain pitch class

  14. Intimate Partner Violence Victimization and Associated Factors ...

    African Journals Online (AJOL)

    AJRH Managing Editor

    Protective factors. Self-rated health status was assessed by a single ... Life satisfaction was elicited with one question,. “All things ... 95% confidence interval (CI) to determine the associations .... severe depression and 21.1% for PTSD. Regarding .... Table 3: Associations with Intimate Partner Violence among Men. Variables.

  15. Cross-cultural color-odor associations

    NARCIS (Netherlands)

    Levitan, C.A.; Ren, J.; Boesveldt, S.; Chan, J.; McKenzie, K.J.; Levin, J.A.; Leong, C.X.; Bosch, van den J.F.

    2014-01-01

    Colors and odors are associated; for instance, people typically match the smell of strawberries to the color pink or red. These associations are forms of crossmodal correspondences. Recently, there has been discussion about the extent to which these correspondences arise for structural reasons (i.e.

  16. Genetic association studies in lumbar disc degeneration

    DEFF Research Database (Denmark)

    Eskola, Pasi J; Lemmelä, Susanna; Kjaer, Per

    2012-01-01

    Low back pain is associated with lumbar disc degeneration, which is mainly due to genetic predisposition. The objective of this study was to perform a systematic review to evaluate genetic association studies in lumbar disc degeneration as defined on magnetic resonance imaging (MRI) in humans....

  17. Sequential association rules in atonal music

    NARCIS (Netherlands)

    Honingh, A.; Weyde, T.; Conklin, D.

    2009-01-01

    This paper describes a preliminary study on the structure of atonal music. In the same way as sequential association rules of chords can be found in tonal music, sequential association rules of pitch class set categories can be found in atonal music. It has been noted before that certain pitch class

  18. Subject Matter Knowledge for Teaching Statistical Association

    Science.gov (United States)

    Casey, Stephanie A.

    2010-01-01

    This study seeks to describe the subject matter knowledge needed for teaching statistical association at the secondary level. Taking a practice-based qualitative approach, three experienced teachers were observed as they taught statistical association and interviewed immediately following each observation. Records of practice were assembled to…

  19. Implicit measures of association in psychopathology research

    NARCIS (Netherlands)

    Roefs, A.; Huijding, J.; Smulders, F.T.Y.; MacLeod, C.M.; de Jong, P.J.; Wiers, R.W.; Jansen, A.T.M.

    2011-01-01

    Studies obtaining implicit measures of associations in Diagnostic and Statistical Manual of Mental Disorders (4th ed., Text Revision; American Psychiatric Association, 2000) Axis I psychopathology are organized into three categories: (a) studies comparing groups having a disorder with controls, (b)

  20. Implicit Measures of Association in Psychopathology Research

    NARCIS (Netherlands)

    Roefs, Anne; Huijding, Jorg; Smulders, Fren T. Y.; MacLeod, Colin M.; de Jong, Peter J.; Wiers, Reinout W.; Jansen, Anita T. M.

    2011-01-01

    Studies obtaining implicit measures of associations in Diagnostic and Statistical Manual of Mental Disorders (4th ed., Text Revision; American Psychiatric Association, 2000) Axis 1 psychopathology are organized into three categories: (a) studies comparing groups having a disorder with controls, (b)

  1. The association of lysozyme with casein

    NARCIS (Netherlands)

    Roos, de A.L.; Walstra, P.; Geurts, T.J.

    1998-01-01

    The association of hen eggs’ lysozyme with caseins was studied by using three casein substrates: (I) solutions of the various caseins, (II) artificially made casein micelles of various compositions and (III) caseins adsorbed onto soya-oil emulsion droplets. In solution, lysozyme associated most stro

  2. Close Associations and Memory in Brainwriting Groups

    Science.gov (United States)

    Coskun, Hamit

    2011-01-01

    The present experiment examined whether or not the type of associations (close (e.g. apple-pear) and distant (e.g. apple-fish) word associations) and memory instruction (paying attention to the ideas of others) had effects on the idea generation performances in the brainwriting paradigm in which all participants shared their ideas by using paper…

  3. Conflict Adaptation by Means of Associative Learning

    Science.gov (United States)

    Braem, Senne; Verguts, Tom; Notebaert, Wim

    2011-01-01

    Cognitive control is responsible for adapting information processing in order to carry out tasks more efficiently. Contrasting global versus local control accounts, it has recently been proposed that control operates in an associative fashion, that is, by binding stimulus-response associations after detection of conflict (Verguts & Notebaert,…

  4. Retroperitoneal liposarcoma associated with small plaque parapsoriasis

    OpenAIRE

    Polichetti Paolo; Sgueglia Monica; Blasi Sara; Tartaglia Francesco; Tromba Luciana; Berni Alberto

    2007-01-01

    Abstract Background Extremely rare cases of paraneoplastic syndromes or ectopic production of proteins associated with liposarcoma are reported in literature. Production of Granulocyte-Colony Stimulating Factor, alpha-fetoprotein, paraneoplastic pemphigus and leucocytosis, Acrokeratosis paraneoplastica (Bazex's syndrome) are reported. The present report describes a case of retroperitoneal liposarcoma associated with small plaque parapsoriasis. Our search in the English literature of such a ki...

  5. Clavicular osteoma associated with bronchial osteomas

    Energy Technology Data Exchange (ETDEWEB)

    Saglik, Yener; Yiliz, H. Yusuf; Erakar, Aziz [Department of Orthopaedic Surgery, Ankara University School of Medicine, 06100, Ankara (Turkey); Kendi, Tuba Karaguelle [Integra MR Imaging Center, Ankara (Turkey); CMRR, University of Minnesota, 2021 6th Street SE, MN 55455, Minneapolis (United States); Guengoer, Adem [Department of Chest Surgery, Ankara University School of Medicine, 06100, Ankara (Turkey); Erekul, Selim [Department of Pathology, Ankara University School of Medicine, 06100, Ankara (Turkey)

    2004-04-01

    Osteoma is a rare benign tumor, composed of bony tissues. It predominantly involves the skull but rarely the long bones. In this report we present a case of clavicular osteoma associated with bronchial osteomas. This association has not previously been reported. There was no evidence of Gardner's syndrome. (orig.)

  6. [Retroperitoneal fibrosis and multiple myeloma: fortuitous association?].

    Science.gov (United States)

    Sinapi, I; Caers, J; Connerotte, T; Koutaissoff, S; Lambert, M

    2010-05-01

    We report a 59-year-old man presenting with retroperitoneal fibrosis (RF) associated with IgG lambda multiple myeloma. Recent clinical and immunohistochemical findings suggest that RF might be a particular expression of plasma cell/lymphoid dyscrasia, and that this association is not merely fortuitous. We review the pathophysiological evidence supporting this hypothesis.

  7. Teaching Strategies Associated with Conceptual Change Learning.

    Science.gov (United States)

    Smith, Edward L.; And Others

    1993-01-01

    Teaching strategies associated with a conceptual change model of science teaching were examined in a study of seventh-grade life science teachers (n=13). Greater use of conceptual change teaching strategies was associated with use of the special instructional materials, not with the training. Students in classes where teachers were provided with…

  8. Local Dynamic Stability Associated with Load Carrying

    Directory of Open Access Journals (Sweden)

    Jian Liu

    2013-03-01

    Conclusion: Current study confirmed the sensitivity of local dynamic stability measure in load carrying situation. It was concluded that load carrying tasks were associated with declined local dynamic stability, which may result in increased risk of fall accident. This finding has implications in preventing fall accidents associated with occupational load carrying.

  9. Close Associations and Memory in Brainwriting Groups

    Science.gov (United States)

    Coskun, Hamit

    2011-01-01

    The present experiment examined whether or not the type of associations (close (e.g. apple-pear) and distant (e.g. apple-fish) word associations) and memory instruction (paying attention to the ideas of others) had effects on the idea generation performances in the brainwriting paradigm in which all participants shared their ideas by using paper…

  10. 11 CFR 114.8 - Trade associations.

    Science.gov (United States)

    2010-01-01

    ... administrative personnel of the corporate members of its member associations. (h) Communications other than... Elections FEDERAL ELECTION COMMISSION GENERAL CORPORATE AND LABOR ORGANIZATION ACTIVITY § 114.8 Trade... authorization specifically allowing a trade association to solicit its corporate member's stockholders,...

  11. Learned Interval Time Facilitates Associate Memory Retrieval

    Science.gov (United States)

    van de Ven, Vincent; Kochs, Sarah; Smulders, Fren; De Weerd, Peter

    2017-01-01

    The extent to which time is represented in memory remains underinvestigated. We designed a time paired associate task (TPAT) in which participants implicitly learned cue-time-target associations between cue-target pairs and specific cue-target intervals. During subsequent memory testing, participants showed increased accuracy of identifying…

  12. Common oral lesions associated with HIV infection.

    Science.gov (United States)

    Navazesh, M; Lucatorto, F

    1993-09-01

    More than 40 different lesions involving head and neck areas have been associated with HIV infection. The oral cavity may manifest the first sign of HIV infection. Early detection of these conditions can lead to early diagnosis of HIV infection and subsequent appropriate management. Signs, symptoms and management of the most common HIV-associated oral lesions are discussed.

  13. Open Clusters and OB Associations: a Review

    Directory of Open Access Journals (Sweden)

    Anthony G. A. Brown

    2001-01-01

    Full Text Available In this review on open clusters and OB associations I discuss some recent developments to which Latin American astronomers have contributed. Subsequently, results from the Hipparcos mission concerning OB associations, the Hyades and other nearby open clusters will be discussed. I end with a brief discussion of current theories of star cluster formation and prospects for future research.

  14. Obesity-associated cancer: an immunological perspective.

    Science.gov (United States)

    Conroy, Melissa J; Dunne, Margaret R; Donohoe, Claire L; Reynolds, John V

    2016-05-01

    Epidemiological studies have established an association between obesity, insulin resistance, type 2 diabetes and a number of cancer types. Research has focused predominantly on altered endocrine factors, growth factors and signalling pathways, with little known in man about the immune involvement in the relevant pathophysiological processes. Moreover, in an era of exciting new breakthroughs in cancer immunotherapy, there is also a need to study the safety and efficacy of immunotherapeutics in the complex setting of inflammatory-driven obesity-associated cancer. This review addresses key immune cell subsets underpinning obesity-associated inflammation and describes how such immune compartments might be targeted to prevent and treat obesity-associated cancer. We propose that the modulation, metabolism, migration and abundance of pro- and anti-inflammatory cells and tumour-specific T cells might be therapeutically altered to both restore immune balance, alleviating pathological inflammation, and to improve anti-tumour immune responses in obesity-associated cancer.

  15. Association Rule Discovery and Its Applications

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Data mining, i.e. , mining knowledge from large amounts of data, is a demanding field since huge amounts of data have been collected in various applications. The collected data far exceed peoples ability to analyze it. Thus, some new and efficient methods are needed to discover knowledge from large database. Association rule discovery is an important problem in knowledge discovery and data mining.The association mining task consists of identifying the frequent item sets and then forming conditional implication rule among them. In this paper, we describe and summarize recent work on association rule discovery, offer a new method to association rule mining and point out that association rule discovery can be applied in spatial data mining. It is useful to discover knowledge from remote sensing and geographical information system.``

  16. Effective Discovery of Exception Class Association Rules

    Institute of Scientific and Technical Information of China (English)

    周傲英; 魏藜; 俞舫

    2002-01-01

    In this paper, a new effective method is proposed to find class association rules (CAR), to get useful class association rules (UCAR) by removing the spurious class association rules (SCAR), and to generate exception class association rules (ECAR) for each UCAR. CAR mining, which integrates the techniques of classification and association, is of great interest recently. However, it has two drawbacks: one is that a large part of CARs are spurious and maybe misleading to users; the other is that some important ECARs are difficult to find using traditional data mining techniques. The method introduced in this paper aims to get over these flaws. According to our approach, a user can retrieve correct information from UCARs and know the influence from different conditions by checking corresponding ECARs. Experimental results demonstrate the effectiveness of our proposed approach.

  17. The different roles of the Staff association

    CERN Multimedia

    Staff Association

    2012-01-01

    The statutory role of the CERN Staff Association is defined in Chapter VII of the Staff Rules and Regulations. The means of the Association to realize its aims are described in Article I.1.3 of the Statutes of the CERN Staff Association. Generally speaking, its aims are “To serve and defend the economic, social, professional and moral interests of its members and all CERN staff“. Usually we deal with professional and social issues (employment conditions, defence of collective or individual rights, promotion of basic research...). But the Association also plays a role of integration (clubs promoting cultural, humanitarian, and sport or offering entertainment, organizing exhibitions and conferences) and it can promote actions to provide its members with material or social advantages (Interfon, commercial offers). Advantageous commercial offers In recent years the Association was able to negotiate with business or cultural partners benefits for its members. A full list can be found on our...

  18. Experimental and numerical study of two-phase flows at the inlet of evaporators in vapour compression cycles; Etude experimentale et numerique d'ecoulements diphasiques a l'entree des evaporateurs de cycles thermodynamiques

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, M

    2007-09-15

    Maldistribution of liquid-vapour two phase flows causes a significant decrease of the thermal and hydraulic performance of evaporators in thermodynamic vapour compression cycles. A first experimental installation was used to visualize the two phase flow evolution between the expansion valve and the evaporator inlet. A second experimental set-up simulating a compact heat exchanger has been designed to identify the functional and geometrical parameters creating the best distribution of the two phases in the different channels. An analysis and a comprehension of the relation between the geometrical and functional parameters with the flow pattern inside the header and the two phase distribution, has been established. A numerical simulations of a stratified flow and a stratified jet flow have been carried out using two CFD codes: FLUENT and NEPTUNE. In the case of a fragmented jet configuration, a global definition of the interfacial area concentration for a separated phases and dispersed phases flow has been established and a model calculating the fragmented mass fraction has been developed. (author)

  19. General meeting. Technical reunion: the numerical and experimental simulation applied to the Reactor Physics; Assemblee generale. Reunion technique: la simulation numerique et experimentale appliquee a la physique des reacteurs

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-10-01

    The SFEN (French Society on Nuclear Energy), organized the 18 october 2001 at Paris, a technical day on the numerical and experimental simulation, applied to the reactor Physics. Nine aspects were discussed, giving a state of the art in the domain:the french nuclear park; the future technology; the controlled thermonuclear fusion; the new organizations and their implications on the research and development programs; Framatome-ANP markets and industrial code packages; reactor core simulation at high temperature; software architecture; SALOME; DESCARTES. (A.L.B.)

  20. Directory of Factual and Numeric Databases of Relevance to Aerospace and Defence R and D (Repertoire de Bases de donnees Factuelles ou Numeriques d’interet pour la R and D).

    Science.gov (United States)

    1992-07-01

    Tecnica Aeroespacial [INTA]) ADDRESS/POINT OF CONTACT: Attention: Elisa Sugranez Puerto Pinto Rosales, 34 28008 Madrid, Spain Fax: 34 (1) 2480872...atmospheric molecular extinction coefficients, total extinction ratios, ozone and N02 mixing ratios, and corresponding error arrays as a function of

  1. Mathematical and numerical analysis of a multi-velocity multi-fluid model for interpenetration of miscible fluids; Analyse mathematique et numerique d'un modele multifluide multivitesse pour l'interpenetration de fluides miscibles

    Energy Technology Data Exchange (ETDEWEB)

    Enaux, C

    2007-11-15

    The simulation of indirect laser implosion requires an accurate knowledge of the inter-penetration of the laser target materials turned into plasma. This work is devoted to the study of a multi-velocity multi-fluid model recently proposed by Scannapieco and Cheng (SC) to describe the inter-penetration of miscible fluids. In this document, we begin with presenting the SC model in the context of miscible fluids flow modelling. Afterwards, the mathematical analysis of the model is carried out (study of the hyperbolicity, existence of a strictly convex mathematical entropy, asymptotic analysis and diffusion limit). As a conclusion the problem is well set. Then, we focus on the problem of numerical resolution of systems of conservation laws with a relaxation source term, because SC model belongs to this class. The main difficulty of this task is to capture on a coarse grid the asymptotic behaviour of the system when the source term is stiff. The main contribution of this work lies in the proposition of a new technique, allowing us to construct a Lagrangian numerical flux taking into account the presence of the source term. This technique is applied first on the model-problem of a one-dimensional Euler system with friction, and then on the multi-fluid SC model. In both cases, we prove that the new scheme is asymptotic-preserving and entropic under a CFL-like condition. The two-dimensional extension of the scheme is done by using a standard alternate directions method. Some numerical results highlight the contribution of the new flux, compared with a standard Lagrange plus Remap scheme where the source term is processed using an operator splitting. (author)

  2. Numerical study and modeling of turbulence modulation in a sheet flow burdened with particulates; Etude numerique et modelisation de la modulation de la turbulence dans un ecoulement de nappe chargee en particules

    Energy Technology Data Exchange (ETDEWEB)

    Vermorel, O.

    2003-11-15

    This work is devoted to the numerical and theoretical study of turbulence modulation by particles using direct numerical simulation for the continuous phase coupled with a Lagrangian prediction of trajectories of discrete particles. The configuration corresponds to a slab of particles injected at high velocity into an isotropic decaying turbulence. The motion of a particle is supposed to be governed only by the drag force. The particle mass loading is large so that momentum exchange between particles and fluid results in a significant modulation of the turbulence. Collisions are neglected. The momentum transfer between particles and gas causes a strong acceleration of the gas in the slab. In the periphery of the slab, the turbulence is enhanced due to the production by the mean gas velocity gradients. The analysis of the interphase transfer terms in the gas turbulent kinetic energy equation shows that the direct effect of the particles is to damp the turbulence in the core of the slab but to enhance it in the periphery. This last effect is due to a strong correlation between the particle distribution and the instantaneous gas velocity. Another issue concerns the k-{epsilon} model and the validity of its closure assumptions in two phase flows. A new eddy viscosity expression, function of particle parameters, is used to model the Reynolds stress tensor. The modelling of the gas turbulent dissipation rate is questioned. A two-phase Langevin equation is also tested to model drift velocity and fluid-particles velocity covariance equations. (author)

  3. Numerical simulation of the unsteady and turbulent flow in a high-pressure turbine stage; Simulation numerique de l'ecoulement instationnaire et turbulent dans un etage de turbine haute pression

    Energy Technology Data Exchange (ETDEWEB)

    Bastin, G.

    2004-09-15

    The aim of this study concerns the use of numerical methods for the resolution of the Reynolds Averaged Navier Stokes equations adapted to the simulation of the cooling of the trailing edge of a stator in a high pressure turbine. These methods, based on the elsA solver developed at ONERA, use a four steps Runge Kutta time discretization scheme and a Jameson centered space discretization scheme. The scheme is applied through a finite volume approach on control volume centered on the cells of a multi-block structured mesh. Turbulence is simulated either through the algebraic Michel model, or through the one-transport-equation Spalart-Allmaras model, or through the two-transport-equations k 1, k {omega} and k {epsilon} models, and through ASM model. A simulation of the flow in a bidimensional stator, without cooling, is carried out. The cooling, which is realized with trailing edge slots, is then simulated on a bidimensional stator. Because the slot is represented by meshes overlapping the mesh of the smooth blade, the Chimera method is chosen. This method makes it possible computations with overlapping meshes. The comparison with the experimental data, on these two first computations has validated this strategy to represent such slots. The tridimensional simulation of a single stator with taking account of the cooling is then realized. It showed the complex and tridimensional aspects of the main flow with focus on the influence of the cooling system. Finally two steady computations, without and with cooling, and an unsteady computation without cooling are carried out on a high pressure turbine stage. The comparison with the experimental data obtained in the frame of the European Brite-Euram program is made. These results make it possible to determine the effect of the cooling on the flow in a turbine stage. (authors)

  4. Evaluation of turbulent transport and flame surface dissipation using direct numerical simulation of turbulent combustion; Evaluation des termes de transport et de dissipation de surface de flamme par simulation numerique directe de la combustion turbulente

    Energy Technology Data Exchange (ETDEWEB)

    Boughanem, H.

    1998-03-24

    The assumption of gradient transport for the mean reaction progress variable has a limited domain of validity in premixed turbulent combustion. The existence of two turbulent transport regimes, gradient and counter-gradient, is demonstrated in the present work using Direct Numerical Simulations (DNS) of plane flame configurations. The DNS data base describes the influence of the heat release factor, of the turbulence-to-flame velocity ratio, and of an external pressure gradient. The simulations reveal a strong correlation between the regime of turbulent transport and the turbulent flame speed and turbulent flame thickness. These effects re not well described by current turbulent combustion models. A conditional approach `fresh gases / burnt gases` is proposed to overcome these difficulties. Furthermore, he development of flame instabilities in turbulent configurations is also observed in the simulations. A criterion is derived that determines the domain of occurrence of these instabilities (Darrieus- Landau instabilities, Rayleigh- Taylor instabilities, thermo-diffusive instabilities). This criterion suggests that the domain of occurrence of flame instabilities is not limited to small Reynolds numbers. (author) 98 refs.

  5. Reactive turbulent flow CFD study in supercritical water oxidation process: application to a stirred double shell reactor; Etude par simulation numerique des ecoulements turbulents reactifs dans les reacteurs d'oxydation hydrothermale: application a un reacteur agite double enveloppe

    Energy Technology Data Exchange (ETDEWEB)

    Moussiere, S

    2006-12-15

    Supercritical water oxidation is an innovative process to treat organic liquid waste which uses supercritical water properties to mix efficiency the oxidant and the organic compounds. The reactor is a stirred double shell reactor. In the step of adaptation to nuclear constraints, the computational fluid dynamic modeling is a good tool to know required temperature field in the reactor for safety analysis. Firstly, the CFD modeling of tubular reactor confirms the hypothesis of an incompressible fluid and the use of k-w turbulence model to represent the hydrodynamic. Moreover, the EDC model is as efficiency as the kinetic to compute the reaction rate in this reactor. Secondly, the study of turbulent flow in the double shell reactor confirms the use of 2D axisymmetric geometry instead of 3D geometry to compute heat transfer. Moreover, this study reports that water-air mixing is not in single phase. The reactive turbulent flow is well represented by EDC model after adaptation of initial conditions. The reaction rate in supercritical water oxidation reactor is mainly controlled by the mixing. (author)

  6. Application of experimental and numerical techniques to the transfer characterization of aero contaminant in installations; Application des techniques experimentales et numeriques a la caracterisation des transferts d'aerocontaminant dans les installations

    Energy Technology Data Exchange (ETDEWEB)

    Drecourt, S.; Laborde, J.C.; Lacan, J.; Witschger, O. [CEA/Fontenay-aux-Roses, Inst. de Protection et de Surete Nucleaire (IPSN), 92 (France)

    1998-07-01

    In the nuclear field, numerous studies based on the transfer of contamination in air are realised and concern as well the workers protection than the safety of installations: in particular, the ventilation, by its dynamic containment functions, surveillance in cleansing, is brought into operation in order to protect the operators and the outside environment facing a contaminant emission. The ventilation applies in normal conditions of operation and in accidental situations. In the two cases it is necessary to limit the propagation of contaminants and to be sure that a dispersion of contaminant be detected as quickly as possible. (N.C.)

  7. Contribution to numerical simulation for fluid flow, electromagnetism and plasma physics; Contribution aux methodes numeriques pour la simulation d'ecoulements de fluides, d'electromagnetisme et de physique des plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Salmon, St

    2008-07-01

    This work is made of 2 distinct parts. The first part is dedicated to 2 formulations of the Stokes's problem: a classical presentation in the (current, vortex) plane and a new one in the (vortex, speed, pressure) space with an extension for 3-dimensional calculations. The second part is dedicated to different solving of the Vlasov equations coupled with Maxwell equations: the semi-Lagrangian method and the finite element method. This system of equations drives the equilibrium and stability of magnetically confined fusion plasmas.

  8. Experimental thermal study and numerical simulation of a composite solar wall. Optimization of the energetic performances; Etude thermique experimentale et simulation numerique d`un mur solaire composite. Optimisation des performances energetiques

    Energy Technology Data Exchange (ETDEWEB)

    Zalewski, L.

    1996-11-27

    The objective of this work is the analysis of a passive solar component: the composite solar wall, a building component, which includes an insulating panel located behind the massive wall. This panel has two vents located at the top and at the bottom, which allow the air to circulate from the room to the layer in contact with the back of the massive wall, where it is heated, and then back to the room. The solar energy is transferred to the building by conduction through the massive wall, and then by convection using a thermosyphon phenomenon. The monitoring of 2 solar houses in Verdun-Thierville (Meuse, France) has clearly shown, control issues of the air layer. The wall must be operated as autonomously as possible, to not be a constraint for the occupants and to get an optimization of the energy gains. To solve these problems, a composite solar wall prototype was erected in a test cell at Cadarache and tested in real operating conditions. This allows to use a more complete instrumentation, to have access more easily to the sensors and to study various configurations. The first experiments revealed an inverse thermosyphon phenomenon. To avoid this effect, two systems were designed, tested at Cadarache and then implemented in the walls at Verdun. (author) 77 refs.

  9. Mechanical behaviour of nickel foams: three-dimensional morphology, non-linear models and fracture; Caracterisation et simulation numerique du comportement mecanique des mousses de nickel: morphologie tridimensionnelle, reponse elastoplastique et rupture

    Energy Technology Data Exchange (ETDEWEB)

    Dillard, Th.

    2004-03-15

    The deformation behaviour and failure of nickel foams were studied during loading by using X-ray microtomography. Strut alignment and stretching are observed in tension whereas strut bending followed by strut buckling are observed in compression. Strain localisation, that occurs during compression tests, depends on nickel weight distribution in the foam. Fracture in tension first takes place at cell nodes and the crack propagates cell by cell. The damaged area in front of a crack is about five cells wide. A detailed description of the three-dimensional morphology is also presented. One third of the cells are dodecahedral and 57 % of the faces are pentagonal. The most frequent cell is composed of two quadrilaterals, two hexagons and eight pentagons. The dimensions of the equivalent ellipsoid of each cell are identified and cell orientation are determined. The geometrical aspect ratio is linked to the mechanical anisotropy of the foam. In tension, a uniaxial analytical model, based on elastoplastic strut bending, is developed. The whole stress-strain curve of the foam is predicted according to its specific weight and its anisotropy. It is found that the non-linear regime of the macroscopic curve of the foam is not only due to the elastoplastic bending of the struts. The model is also extended to two-phase foams and the influence of the hollow struts is analysed. The two-phase foams model is finally applied to oxidized nickel foams and compared with experimental data. The strong increase in the rigidity of nickel foams with an increasing rate of oxidation, is well described by the model. However, a fracture criterion must also be introduced to take into account the oxide layer cracking. A phenomenological compressible continuum plasticity model is also proposed and identified in tension. The identification of the model is carried out using experimental strain maps obtained by a photo-mechanical technique. A validation of the model is provided by investigating the strain field around a hole in a foam. The multiaxial model is extended to a micro-morphic one to incorporate non local features accounting for the size effects observed for small holes. The prediction of the model is evaluated in the case of subsequent fracture of the specimen through crack propagation. (author)

  10. Local approach: fracture at high temperature in an austenitic stainless steel submitted to thermomechanical loadings. Calculations and experimental validations; Approche locale: fissuration a haute temperature dans un acier inoxydable austenitique sous chargements thermomecaniques. Simulations numeriques et validations experimentales

    Energy Technology Data Exchange (ETDEWEB)

    Poquillon, D

    1997-10-01

    Usually, for the integrity assessment of defective components, well established rules are used: global approach to fracture. A more fundamental way to deal with these problems is based on the local approach to fracture. In this study, we choose this way and we perform numerical simulations of intergranular crack initiation and intergranular crack propagation. This type of damage can be find in components of fast breeder reactors in 316 L austenitic stainless steel which operate at high temperatures. This study deals with methods coupling partly the behaviour and the damage for crack growth in specimens submitted to various thermomechanical loadings. A new numerical method based on finite element computations and a damage model relying on quantitative observations of grain boundary damage is proposed. Numerical results of crack initiation and growth are compared with a number of experimental data obtained in previous studies. Creep and creep-fatigue crack growth are studied. Various specimen geometries are considered: compact Tension Specimens and axisymmetric notched bars tested under isothermal (600 deg C) conditions and tubular structures containing a circumferential notch tested under thermal shock. Adaptative re-meshing technique and/or node release technique are used and compared. In order to broaden our knowledge on stress triaxiality effects on creep intergranular damage, new experiments are defined and conducted on sharply notched tubular specimens in torsion. These isothermal (600 deg C) Mode II creep tests reveal severe intergranular damage and creep crack initiation. Calculated damage fields at the crack tip are compared with the experimental observations. The good agreement between calculations and experimental data shows the damage criterion used can improve the accuracy of life prediction of components submitted to intergranular creep damage. (author) 200 refs.

  11. Alphanumerical classification for the subject files of the department of documentation of the Atomic Energy Commission; Classification alpha-numerique pour le fichier matieres du service de documentation du Commissariat a l'Energie Atomique

    Energy Technology Data Exchange (ETDEWEB)

    Braffort, P.; Iung, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1956-07-01

    The research activities of the Atomic Energy Commission cover a large variety of different subjects from theoretical physics and nuclear physics to biology, medicine or geology. Thus, about 350 scientific reviews are received and presented in the library. All those documents need to be classified to make the research of information easier for researchers. It describes the classification and codification of such a large quantity of documents. The classification uses a bidimensional system with 5 columns with inter-scale phenomena, corpuscular scale, nuclear scale, atomic and molecular scale and macroscopic scale as subject and 5 lines with theoretical problems, production, measurement, description and utilisation as topic. Some of the rules are given and examples are presented. (M.P.)

  12. Experimental and numerical study of the strong interaction between wakes of cylindrical obstacles; Etude experimentale et numerique de l'interaction forte entre sillages d'obstacles cylindriques

    Energy Technology Data Exchange (ETDEWEB)

    Brun, Ch

    1998-04-02

    In the context of thermal-hydraulics of nuclear reactors, strong interaction between wakes is encountered in the bottom of reactor vessels where control and measurement rods of variable size and disposition interact with the overall wakes generated in these flow zones. This study deals with the strong interaction between two wakes developed downstream of two parallel cylinders with a small spacing. The analysis focusses on the effect of the Reynolds regime which controls the equilibrium between the inertia and viscosity forces of the fluid and influences the large scale behaviour of the flow with the development of hydrodynamic instabilities and turbulence. The document is organized as follows: the characteristic phenomena of wakes formation downstream of cylindrical obstacles are recalled in the first chapter (single cylinder, interaction between two tubes, case of a bundle of tubes perpendicular to the flow). The experimental setup (hydraulic loop, velocity and pressure measurement instrumentation) and the statistical procedures applied to the signals measured are detailed in chapters 2 and 3. Chapter 4 is devoted to the experimental study of the strong interaction between two tubes. Laser Doppler velocity measurements in the wakes close to cylinders and pressure measurements performed on tube walls are reported in this chapter. In chapter 5, a 2-D numerical simulation of two typical cases of interaction (Re = 1000 and Re = 5000) is performed. In the last chapter, a more complex application of strong interactions inside and downstream of a bunch of staggered tubes is analyzed experimentally for equivalent Reynolds regimes. (J.S.)

  13. Numerical treatment of the gas dynamics equations with nonlinear heat conduction in the linear perturbation code SileX; Traitement numerique des equations de la dynamique des gaz avec conduction non lineaire dans le code de perturbation SileX

    Energy Technology Data Exchange (ETDEWEB)

    Boudesocque-Dubois, C.; Clarisse, J.M

    2007-07-01

    In the context of linear perturbation computations of planar or spherically symmetric flows, we propose numerical methods, in Lagrangian coordinates, for integrating the one-dimensional gas dynamics equations with nonlinear heat conduction and their linear perturbations. Numerical results are presented for different configurations, with or without flow motion. (authors)

  14. Contributions to the numerical modeling of concrete structures cracking with creep and estimation of the permeability; Contributions a la modelisation numerique de la fissuration des structures en beton avec prise en compte du fluage et estimation de la permeabilite

    Energy Technology Data Exchange (ETDEWEB)

    Dufour, F

    2007-12-15

    The industrial context of this research work is to study the durability of the internal barriers of nuclear power plants. This paper is divided in two parts, the first part is relative to the crack-damage state and the second part to the creep consequences on the rupture properties of concrete. In the first part, the analysis of the experimental results, (carried out on a compression cylinder on which the radial permeability has been measured), shows that the permeability decreases until a deformation of half of those at the force peak, by re-closure of the preexisting microcracks in the material; then the permeability strongly increases until after the force peak by initiation, connexion and opening of the crack, and at last it increases less rapidly until the rupture because only the opening of the macro-cracks increases. In order to simulate these phenomena, two original methods are presented, in post-treatment phase, for estimating the leaks from a mechanical computing based on finite element methods. With the first method, it is possible to measure the permeability from the damage field and from a relation between the permeability and the damage which bind the Poiseuille law to an empirical law established for weak damages. The second method is on the deformations field from which the position and opening of the crack are calculated. The Poiseuille relation is then applied along the crack to estimate the leaks rates. The relation between the concrete creep and its mechanical characteristics is analyzed in the second part. In particular, are studied the creep consequences on the long term mechanical properties. After having given the experimental results which show essentially an embrittlement of the material after creep, a qualitative analysis by the bifurcations study is proposed, and then by a discrete numerical method to find again the same influence of the visco-elasticity on the rupture embrittlement experimentally observed. At last, the first results of the quantitative analysis by a finite element method using an original coupled model are presented. (O.M.)

  15. Numerical modeling of the thermomechanical behavior of networks of underground galleries for the storage of the radioactive waste: approach by homogenization; Modelisation numerique du comportement thermomecanique de reseaux de galeries souterraines pour le stockage des dechets radioactifs: Approche par homogeneisation

    Energy Technology Data Exchange (ETDEWEB)

    Zokimila, P

    2005-10-15

    Deep geological disposal is one of the privileged options for the storage of High Level radioactive waste. A good knowledge of the behavior and properties of the potential geological formations as well as theirs evolution in time under the effect of the stress change induced by a possible installation of storage is required. The geological formation host will be subjected to mechanical and thermal solicitations due respectively to the excavation of the disposal tunnels and the release of heat of the canisters of radioactive waste. These thermomechanical solicitations will generate a stress relief in the host layer and disposal tunnels deformations as well as the extension of the damaged zones (EDZ) could cause local and global instabilities. This work aims to develop calculation methods to optimize numerical modeling of the thermoelastic behavior of the disposal at a large scale and to evaluate thermomechanical disturbance induced by storage on the geological formation host. Accordingly, after a presentation of the state of knowledge on the thermomechanical aspects of the rocks related to deep storage, of numerical modeling 2D and 3D of the thermoelastic behavior of individual disposal tunnel and a network of tunnels were carried out by a discrete approach. However, this classical approach is penalizing to study the global behavior of disposal storage. To mitigate that, an approach of numerical modeling, based on homogenization of periodic structures, was proposed. Formulations as numerical procedures were worked out to calculate the effective thermoelastic behavior of an equivalent heterogeneous structure. The model, obtained by this method, was validated with existing methods of homogenization such as the self-consistent model, as well as the Hashin-Shtrikman bounds. The comparison between the effective thermoelastic behavior and current thermoelastic behavior of reference showed a good coherence of the results. For an application to deep geological storage, the effective thermoelastic properties of a network of circular tunnels could be given in 2D for various dimensions of the distance between galleries. (author)

  16. Numerical study and modeling of turbulence modulation in a sheet flow burdened with particulates; Etude numerique et modelisation de la modulation de la turbulence dans un ecoulement de nappe chargee en particules

    Energy Technology Data Exchange (ETDEWEB)

    Vermorel, O.

    2003-11-15

    This work is devoted to the numerical and theoretical study of turbulence modulation by particles using direct numerical simulation for the continuous phase coupled with a Lagrangian prediction of trajectories of discrete particles. The configuration corresponds to a slab of particles injected at high velocity into an isotropic decaying turbulence. The motion of a particle is supposed to be governed only by the drag force. The particle mass loading is large so that momentum exchange between particles and fluid results in a significant modulation of the turbulence. Collisions are neglected. The momentum transfer between particles and gas causes a strong acceleration of the gas in the slab. In the periphery of the slab, the turbulence is enhanced due to the production by the mean gas velocity gradients. The analysis of the interphase transfer terms in the gas turbulent kinetic energy equation shows that the direct effect of the particles is to damp the turbulence in the core of the slab but to enhance it in the periphery. This last effect is due to a strong correlation between the particle distribution and the instantaneous gas velocity. Another issue concerns the k-{epsilon} model and the validity of its closure assumptions in two phase flows. A new eddy viscosity expression, function of particle parameters, is used to model the Reynolds stress tensor. The modelling of the gas turbulent dissipation rate is questioned. A two-phase Langevin equation is also tested to model drift velocity and fluid-particles velocity covariance equations. (author)

  17. Numerical modelling in building thermo-aeraulics: from CFD modelling to an hybrid finite volume / zonal approach; Modelisation numerique de la thermoaeraulique du batiment: des modeles CFD a une approche hybride volumes finis / zonale

    Energy Technology Data Exchange (ETDEWEB)

    Bellivier, A.

    2004-05-15

    For 3D modelling of thermo-aeraulics in building using field codes, it is necessary to reduce the computing time in order to model increasingly larger volumes. The solution suggested in this study is to couple two modelling: a zonal approach and a CFD approach. The first part of the work that was carried out is the setting of a simplified CFD modelling. We propose rules for use of coarse grids, a constant effective viscosity law and adapted coefficients for heat exchange in the framework of building thermo-aeraulics. The second part of this work concerns the creation of fluid Macro-Elements and their coupling with a calculation of CFD finite volume type. Depending on the boundary conditions of the problem, a local description of the driving flow is proposed via the installation and use of semi-empirical evolution laws. The Macro-Elements is then inserted in CFD computation: the values of velocity calculated by the evolution laws are imposed on the CFD cells corresponding to the Macro-Element. We use these two approaches on five cases representative of thermo-aeraulics in buildings. The results are compared with experimental data and with traditional RANS simulations. We highlight the significant gain of time that our approach allows while preserving a good quality of numerical results. (author)

  18. Mathematical and numerical analysis of the resistive magnetohydrodynamics system with self-generated magnetic field terms; Analyse mathematique et numerique du systeme de la magnetohydrodynamique resistive avec termes de champ magnetique auto-genere

    Energy Technology Data Exchange (ETDEWEB)

    Wolff, Marc

    2011-10-14

    This work is devoted to the construction of numerical methods that allow the accurate simulation of inertial confinement fusion (ICF) implosion processes by taking self-generated magnetic field terms into account. In the sequel, we first derive a two-temperature resistive magnetohydrodynamics model and describe the considered closure relations. The resulting system of equations is then split in several subsystems according to the nature of the underlying mathematical operator. Adequate numerical methods are then proposed for each of these subsystems. Particular attention is paid to the development of finite volume schemes for the hyperbolic operator which actually is the hydrodynamics or ideal magnetohydrodynamics system depending on whether magnetic fields are considered or not. More precisely, a new class of high-order accurate dimensionally split schemes for structured meshes is proposed using the Lagrange re-map formalism. One of these schemes' most innovative features is that they have been designed in order to take advantage of modern massively parallel computer architectures. This property can for example be illustrated by the dimensionally split approach or the use of artificial viscosity techniques and is practically highlighted by sequential performance and parallel efficiency figures. Hyperbolic schemes are then combined with finite volume methods for dealing with the thermal and resistive conduction operators and taking magnetic field generation into account. In order to study the characteristics and effects of self-generated magnetic field terms, simulation results are finally proposed with the complete two-temperature resistive magnetohydrodynamics model on a test problem that represents the state of an ICF capsule at the beginning of the deceleration phase. (author)

  19. Electronic compensation for breast external radiotherapy: use of digital reconstruct radiograph; Compensation electronique dans les traitements de cancer du sein par irradiation: utilisation des radiographies numeriques reconstruites (digital reconstruct radiograph [DRR])

    Energy Technology Data Exchange (ETDEWEB)

    Gres, B.; Foulquier, J.N.; Orthuon, A.; Huguet, F.; Keraudy, K.; Touboul, E. [Hopital Tenon, Service de Radiotherapie, 75 - Paris (France)

    2009-06-15

    Purpose In case of external breast radiotherapy, the usual treatment consists of two tangential beams homogeneously attenuated by a dynamic or physics wedge in order to obtain the most homogeneous dose distribution as possible. Depending of the shape and size of the breast volume, we may observe with this technique dose heterogeneity over 20% from the recommendation of the International Committee on Radiation Units and Measurements (95-107%). We propose to study breast treatment planning by compensating tissues thickness in order to decrease dose heterogeneity observed on the dose distribution for conventional treatment. Materials and methods We have segmented the initial tangential beams used for this kind of treatment into several smaller beams. Their shape was adapted to the distribution of the greys level on the D.R.R. image. Therefore, we have compensated the thickness gradient and we have given the right dose to the right thickness group. Results Dose distribution performed with this method shows an improvement of the dose homogeneity in the three space dimensions and a decrease of the maximal dose between 5 and 10% over the ICRU recommendation. Conclusion This technique allows us to perform breast irradiation on a single photon energy linac even if the treated volume presents important thickness gradient. However, in case of large breast, this method is not able to reduce the overdosage at the entry of the volume due to inappropriate photon energy relative to the breast thickness. (authors)

  20. Contributions to a rational design of heterogeneous catalysts: from experimentation to numerical simulation; Contributions a une conception rationnelle des catalyseurs heterogenes: de l'experimentation a la simulation numerique

    Energy Technology Data Exchange (ETDEWEB)

    Toulhoat, H.

    2002-03-01

    I present through this dissertation a synthesis of my contributions to the field of heterogeneous catalysis, along two decades of research undertaken as a scientist at Institut Francais du Petrole. I started my itinerary on the 'floor', with the task of developing industrial hydro-treating catalysts, then I had the nice opportunity to lead advanced research on various subjects. However, I have been devoting myself for the past ten years to the encounter between catalysis and theoretical chemistry. The presentation of my work follows therefore a guideline starting with preparation and ending at modelization of the catalytic solid, after having gone through its characterization and the assessment of its activity. Modelization is thus founded on a consistent set of experimental informations. This guideline is applied to the four main themes to which this work is confined: hydro-treating catalysts, hydro-de-metallation catalysts, thio-resistance of noble metals, and solid acids. In summary, I believe I have contributed significantly, on the one hand to strong conceptual and technical advances in the area of ab initio simulation of elementary phenomena in heterogeneous catalysis, with the elaboration of original knowledge on catalysis by sulfides, metals and acids, as well as the genesis of alumina carriers, and on the other hand to a new approach of periodic trends in catalysis: this can be considered as a re-visitation of the principle of Sabatier, leading to a predictive tool for catalytic activity of solids. In a near future it will be possible to say if practical results validate this conceptual tool, and justify or not the ambitious title I gave to my work. (author)

  1. Mixed dual finite element methods for the numerical treatment of the diffusion equation in hexagonal geometry; Elements finis mixtes duaux pour la resolution numerique de l'equation de la diffusion neutronique en geometrie hexagonale

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, D

    2001-07-01

    The nodal method Minos has been developed to offer a powerful method for the calculation of nuclear reactor cores in rectangular geometry. This method solves the mixed dual form of the diffusion equation and, also of the simplified P{sub N} approximation. The discretization is based on Raviart-Thomas' mixed dual finite elements and the iterative algorithm is an alternating direction method, which uses the current as unknown. The subject of this work is to adapt this method to hexagonal geometry. The guiding idea is to construct and test different methods based on the division of a hexagon into trapeze or rhombi with appropriate mapping of these quadrilaterals onto squares in order to take into advantage what is already available in the Minos solver. The document begins with a review of the neutron diffusion equation. Then we discuss its mixed dual variational formulation from a functional as well as from a numerical point of view. We study conformal and bilinear mappings for the two possible meshing of the hexagon. Thus, four different methods are proposed and are completely described in this work. Because of theoretical and numerical difficulties, a particular treatment has been necessary for methods based on the conformal mapping. Finally, numerical results are presented for a hexagonal benchmark to validate and compare the four methods with respect to pre-defined criteria. (authors)

  2. Development of numerical methods to calculate the propagation and the absorption of the hybrid wave in tokamaks; Developpement des methodes numeriques pour la resolution de la propagation et de l`absorption de l`onde hybride dans les tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Sebelin, E

    1997-12-15

    Full-wave calculations based on trial functions are carried out for solving the lower hybrid current drive problem in tokamaks. A variational method is developed and provides an efficient system to describe in a global manner both the propagation and the absorption of the electromagnetic waves in plasmas. The calculation is fully carried out in the case of circular and concentric flux surfaces. The existence and uniqueness of the solution of the wave propagation equation is mathematically proved. The first realistic simulations are performed for the high aspect ratio tokamak TRIAM-1M. It is checked that the main features of the lower-hybrid wave dynamics are well described numerically. (A.C.) 81 refs.

  3. Numerical modelling 2 D and 3 D of circulating fluidized bed: application to the realization of regime diagrams; Modelisation numerique 2D et 3D de lit fluidise circulant: application a la realisation du diagramme des regimes

    Energy Technology Data Exchange (ETDEWEB)

    Begis, J.; Balzer, G.

    1997-02-01

    The numerical modelling of internal CFB boilers flows faced with complex phenomenons due to the flows un-stationariness, the heterogeneousness of the particle size distribution, and interactions between the two phases and the walls. Our study consisted in applying numerical models to the experimental configuration of cold circulating fluidized bed studied at the Cerchar. Special attention was given to the analysis of particles - wall interactions models, stemming from Jenkins (1992) and Louge`s (1994) theories, as well as the influence of the particles on fluid turbulence. In order to realize numerical simulations, we have used Eulerian two-phases flow codes developed at NHL medolif(2D), ESTET-ASTRID(3D). From different tests we have deducted that the most appropriate model for the realization of CFB`s prediction is the model taking in account the influence of particles on fluid turbulence. Then, to evaluate the validity limits of this model, we have built the regime diagram, and we have compared it with the experimental diagram. We have concluded that the simulation allows to describe the different CFB`s working regimes, and especially transitions. We have also noticed the importance of the choice of the mean diameter of the simulated particles. In this way, making a correction of the simulated particles` diameter in comparison with Sauter mean particle diameter, we obtained numerical results in good agreement with experimental data. (authors) 13 refs.

  4. Parallel direct numerical simulation of turbulent flows in rotor-stator cavities. Comparison with k-{epsilon} modeling; Simulation numerique directe parallele d`ecoulements turbulents en cavites rotor-stator comparaisons avec les modilisations k-{epsilon}

    Energy Technology Data Exchange (ETDEWEB)

    Jacques, R.; Le Quere, P.; Daube, O. [Centre National de la Recherche Scientifique (CNRS), 91 - Orsay (France)

    1997-12-31

    Turbulent flows between a fixed disc and a rotating disc are encountered in various applications like turbo-machineries or torque converters of automatic gear boxes. These flows are characterised by particular physical phenomena mainly due to the effects of rotation (Coriolis and inertia forces) and thus, classical k-{epsilon}-type modeling gives approximative results. The aim of this work is to study these flows using direct numerical simulation in order to provide precise information about the statistical turbulent quantities and to improve the k-{epsilon} modeling in the industrial MATHILDA code of the ONERA and used by SNECMA company (aerospace industry). The results presented are restricted to the comparison between results obtained with direct simulation and results obtained with the MATHILDA code in the same configuration. (J.S.) 8 refs.

  5. Determination of the turbulent viscosity inside a strongly heated rectangular jet: experimental and numerical studies; Determination de la viscosite turbulente dans un jet rectangulaire fortement chauffe: etudes experimentale et numerique

    Energy Technology Data Exchange (ETDEWEB)

    Sarh, B.; Gokalp, I.; Sanders, H. [Centre National de la Recherche Scientifique (CNRS), 45 - Orleans-la-Source (France)

    1997-12-31

    In the framework of the studies carried out by the LCSR on variable density flows and diffusion turbulent flames, this paper deals with the study of the influence of density variation on the characteristics of a heated rectangular turbulent jet emerging in a stagnant surrounding atmosphere and more particularly on the determination of turbulent viscosity. The dynamical field is measured using laser-Doppler anemometry while the thermal field is measured using cold wire anemometry. A numerical predetermination of the characteristics of this jet, based on a k-{epsilon} modeling, is carried out. (J.S.) 6 refs.

  6. Numerical modelling of coupled phenomena within molten glass heated by induction and mechanically stirred; Modelisation numerique de phenomenes couples dans des bains de verre brasses mecaniquement et elabores en creuset froid inductif

    Energy Technology Data Exchange (ETDEWEB)

    Jacoutot, L

    2006-11-15

    This study reports on a new vitrification process developed by the French Atomic Energy Commission (CEA, Marcoule). This process is used for the treatment of high activity nuclear waste. It is characterized by the cooling of all the metal walls and by currents directly induced inside the molten glass. In addition, a mechanical stirring device is used to homogenize the molten glass. The goal of this study is to develop numerical tools to understand phenomena which take place within the bath and which involve thermal, hydrodynamic and electromagnetic aspects. The numerical studies are validated using experimental results obtained from pilot vitrification facilities. (author)

  7. CFD Techniques for Propulsion Applications Panel Symposium (77th), Held in San Antonio, Texas on 27-31 May 1991 (Les Techniques de l’Aerodynamique Numerique pour les Applications aux Propulseurs)

    Science.gov (United States)

    1992-02-01

    la paroi. Cette force est directement lite A un coefficient de frottement donn6 tant que ’dcoulement W’est pas ralenti, sinan elke depend du gradient...montre que dans Ic cms avec pertes, les amplitudes ont des valeurs beaucoup plus 6lev~es que dans le cms sans coefficient de frottement constant aux

  8. Numerical modeling of the dynamic behavior of structures under impact with a discrete elements / finite elements coupling; Modelisation numerique du comportement dynamique de structures sous impact severe avec un couplage elements discrets / elements finis

    Energy Technology Data Exchange (ETDEWEB)

    Rousseau, J.

    2009-07-15

    That study focuses on concrete structures submitted to impact loading and is aimed at predicting local damage in the vicinity of an impact zone as well as the global response of the structure. The Discrete Element Method (DEM) seems particularly well suited in this context for modeling fractures. An identification process of DEM material parameters from macroscopic data (Young's modulus, compressive and tensile strength, fracture energy, etc.) will first be presented for the purpose of enhancing reproducibility and reliability of the simulation results with DE samples of various sizes. Then, a particular interaction, between concrete and steel elements, was developed for the simulation of reinforced concrete. The discrete elements method was validated on quasi-static and dynamic tests carried out on small samples of concrete and reinforced concrete. Finally, discrete elements were used to simulate impacts on reinforced concrete slabs in order to confront the results with experimental tests. The modeling of a large structure by means of DEM may lead to prohibitive computation times. A refined discretization becomes required in the vicinity of the impact, while the structure may be modeled using a coarse FE mesh further from the impact area, where the material behaves elastically. A coupled discrete-finite element approach is thus proposed: the impact zone is modeled by means of DE and elastic FE are used on the rest of the structure. An existing method for 3D finite elements was extended to shells. This new method was then validated on many quasi-static and dynamic tests. The proposed approach is then applied to an impact on a concrete structure in order to validate the coupled method and compare computation times. (author)

  9. Implicit upwind schemes for computational fluid dynamics. Solution by domain decomposition; Etude des schemas decentres implicites pour le calcul numerique en mecanique des fluides. Resolution par decomposition de domaine

    Energy Technology Data Exchange (ETDEWEB)

    Clerc, S

    1998-07-01

    In this work, the numerical simulation of fluid dynamics equations is addressed. Implicit upwind schemes of finite volume type are used for this purpose. The first part of the dissertation deals with the improvement of the computational precision in unfavourable situations. A non-conservative treatment of some source terms is studied in order to correct some shortcomings of the usual operator-splitting method. Besides, finite volume schemes based on Godunov's approach are unsuited to compute low Mach number flows. A modification of the up-winding by preconditioning is introduced to correct this defect. The second part deals with the solution of steady-state problems arising from an implicit discretization of the equations. A well-posed linearized boundary value problem is formulated. We prove the convergence of a domain decomposition algorithm of Schwartz type for this problem. This algorithm is implemented either directly, or in a Schur complement framework. Finally, another approach is proposed, which consists in decomposing the non-linear steady state problem. (author)

  10. Expert supervision and adaptative control of biotechnological processes. Utilization of an interactive numerical simulation module; Supervision experte et commande adaptative de procedes biotechnologiques. Utilisation d`un module de simulation numerique interactif

    Energy Technology Data Exchange (ETDEWEB)

    Dahhou, B.; Pourciel, J.B.; Trave Massuyes, L.

    1995-12-31

    This bioreactor control system is based on an expert system achieving a prediction of substrate consumption. It uses a biological model of fermentation, built for that purpose. It should be implanted on a pilot plant at Aramon. (D.L.) 12 refs.

  11. Towards a quantification of stress corrosion mechanisms: numerical simulations of hydrogen-dislocations at the very crack tip; Vers une quantification des mecanismes de corrosion sous contrainte: simulations numeriques des interactions hydrogene-dislocations en pointe de fissure

    Energy Technology Data Exchange (ETDEWEB)

    Chateau, J.P

    1999-01-05

    We discuss the respective roles played by anodic dissolution and hydrogen in SCC mechanisms of f.c.c. materials, by studying the fracture of copper in nitrite for which we compare the results with that previously obtained in 316L steel in hot chloride. It is surprising to note that even the crystallographies at the scale of the micron are different, the macroscopic inclination of the fracture surfaces are the same. In the case of 316L steel, the formation of strong pile-ups in the presence of hydrogen leads to a zigzag fracture along alternated slip planes in the most general case. In the absence of hydrogen, as in copper, this mechanism effectively disappears. Furthermore, numerical simulations of crack shielding by dislocations emitted on one plane predict the macroscopic inclination. It shows that it is due to the mere dissolution which confines slip activity at the very crack tip in f.c.c. materials. In order to quantify the mechanism involved in 316L steel, we developed simulations which numerically solve the coupled diffusion and elasticity equations for hydrogen in the presence of a crack and shielding dislocations. They reproduce the mechanisms of hydrogen segregation on edge dislocations and of a localised softening effect by decreasing pair interactions. These mechanisms lead to i) a localisation of hydrogen embrittlement along the activated slip planes, ii) an increase of the dislocation density in pile-ups, and iii) a decrease of the cross slip probability. These three factors enhance micro-fracture at the head of a pile-up, which is responsible of thezigzag fracture. Introducing the free surface effects for hydrogen, we point out a new mechanism: the inhibition of dislocation sources at the crack tip, which is relevant with the brittle fracture surfaces observed in some cases in 316L steel. The quantification of these different mechanisms allows to give a relation between the local fracture possibility and the macroscopic parameters. A general law for softening is proposed, and we show that micro-fracture occurs for realistic values of three key parameters: hydrogen concentration, decrease of k{sub lc} and obstacle resistance. (author)

  12. Self-focusing and filamentation of a laser beam within the paraxial stationary approximation. Part II: computer simulations; Autofocalisation et filamentation d`un faisceau laser dans le cadre de l`approximation paraxiale et stationnaire. Partie II: simulations numeriques

    Energy Technology Data Exchange (ETDEWEB)

    Blain, M.A.; Bonnaud, G.; Chiron, A.; Riazuelo, G.

    1996-02-01

    This report addresses the propagation of an intense laser beam in a unmagnetized plasma, which is relevant for both the inertial confinement fusion (ICF) and the ultra-high intensity (UHI) pulses. The width and the irradiance of the laser pulses are respectively: (0.1-10) nanosecond and (10{sup 13}-10{sup 16}) W/cm{sup 2} for the ICF context and (0.1-1) picosecond and in excess of 10{sup 1}8 W/cm{sup 2} for the UHI context. The nonlinear mechanisms for beam self-focusing and filamentation, induced by both the ponderomotive expelling of charged particles and the relativistic increase of the electron mass, are specified studied. Part I deals with the theoretical aspects and part II is concerned with the results of two-dimensional simulations. The results have been obtained within the framework of the paraxial approximation and the stationary response of the plasma. The large set of scenarios that characterize the behavior of Gaussian beam and a modulated beam is presented; a synthetic overview of the previous theoretical works is also provided. The interplay of two crossing beams is discussed. This report will be a help to improve the uniformity of the laser irradiation in the ICF context and to channel a very intense laser beam over large distance in the UHI context. (authors). 17 refs., 53 figs., 14 tabs.

  13. Direct numerical simulation and modeling of turbulent natural convection in a vertical differentially heated slot; Simulation numerique directe et modelisation de la convection naturelle turbulente dans un canal differentiellement chauffe

    Energy Technology Data Exchange (ETDEWEB)

    Boudjemadi, R.

    1996-03-01

    The main objectives of this thesis are the direct numerical simulation of natural convection in a vertical differentially heated slot and the improvements of second-order turbulence modelling. A three-dimensional direct numerical simulation code has been developed in order to gain a better understanding of turbulence properties in natural convection flows. This code has been validated in several physical configurations: non-stratified natural convection flows (conduction solution), stratified natural convection flows (double boundary layer solution), transitional and turbulent Poiseuille flows. For the conduction solution, the turbulent regime was reached at a Rayleigh number of 1*10{sup 5} and 5.4*10{sup 5}. A detailed analysis of these results has revealed the principal qualities of the available models but has also pointed our their shortcomings. This data base has been used in order to improve the triple correlations transport models and to select the turbulent time scales suitable for such flows. (author). 122 refs., figs., tabs., 4 appends.

  14. Asymptotic analysis, direct numerical simulation and modeling of premixed turbulent flame-wall interaction; Etude asymptotique, simulation numerique directe et modelisation de l`interaction flamme turbulente premelangee-paroi

    Energy Technology Data Exchange (ETDEWEB)

    Bruneaux, G.

    1996-05-20

    Premixed turbulent flame-wall interaction is studied using theoretical and numerical analysis. Laminar interactions are first investigated through a literature review. This gives a characterization of the different configurations of interaction and justifies the use of simplified kinetic schemes to study the interaction. Calculations are then performed using Direct Numerical Simulation with a one-step chemistry model, and are compared with good agreements to asymptotic analysis. Flame-wall distances and wall heat fluxes obtained are compared successfully with those of the literature. Heat losses decrease the consumption rate, leading to extinction at the maximum of wall heat flux. It is followed by a flame retreat, when the fuel diffuses into the reaction zone, resulting in low unburnt hydrocarbon levels. Then, turbulent regime is investigated, using two types of Direct Numerical Simulations: 2D variable density and 3D constant density. Similar results are obtained: the local turbulent flame behavior is identical to a laminar interaction, and tongues of fresh gases are expelled from the wall region, near zones of quenching. In the 2D simulations, minimal flame-wall distances and maximum wall heat fluxes are similar to laminar values. However, the structure of the turbulence in the 3D calculations induces smaller flame-wall distances and higher wall heat fluxes. Finally, a flame-wall interaction model is built and validated. It uses the flamelet approach, where the flame is described in terms of consumption speed and flame surface density. This model is simplified to produce a law of the wall, which is then included in a averaged CFD code (Kiva2-MB). It is validated in an engine calculation. (author) 36 refs.

  15. Numerical modeling for the electromagnetic non-destructive evaluation: application to the non-destructive evaluation of concrete; Modelisation numerique pour l'evaluation non destructive electromagnetique: application au controle non destructif des structures en beton

    Energy Technology Data Exchange (ETDEWEB)

    Travassos, L

    2007-06-15

    Concrete is the most common building material and accounts for a large part of the systems that are necessary for a country to operate smoothly including buildings, roads, and bridges. Nondestructive testing is one of the techniques that can be used to assess the structural condition. It provides non perceptible information that conventional techniques of evaluation unable to do. The main objective of this work is the numerical simulation of a particular technique of nondestructive testing: the radar. The numerical modeling of the radar assessment of concrete structures make it possible to envisage the behavior of the system and its capacity to detect defects in various configurations. To achieve this objective, it was implemented electromagnetic wave propagation models in concrete structures, by using various numerical techniques to examine different aspects of the radar inspection. First of all, we implemented the finite-difference time-domain method in 3D which allows to take into account concrete characteristics such as porosity, salt content and the degree of saturation of the mixture by using Debye models. In addition, a procedure to improve the radiation pattern of bow-tie antennas is presented. This approach involves the Moment Method in conjunction with the Multi objective Genetic Algorithm. Finally, we implemented imaging algorithms which can perform fast and precise characterization of buried targets in inhomogeneous medium by using three different methods. The performance of the proposed algorithms is confirmed by numerical simulations. (author)

  16. LHS (latin hypercubes) sampling of the material properties of steels for the analysis of the global sensitivity in welding numerical simulation; Echantillonnage LHS des proprietes materiau des aciers pour l analyse de sensibilite globale en simulation numerique du soudage

    Energy Technology Data Exchange (ETDEWEB)

    Petelet, Matthieu; Asserin, Olivier [CEA, DRT / LITEN / DTH / LTA, Bat 611, 91191 Gif sur Yvette Cedex (France); Iooss, Bertrand [CEA, DEN / CAD / DER / SESI / LCFR, Bat 212, 13108 St-Paul-lez-Durance Cedex (France); Petelet, Matthieu; Loredo, Alexandre [ISAT / LRMA, 49 rue Melle Bourgeois, BP 31, 58027 Nevers Cedex (France)

    2006-07-01

    In this work, the method of sensitivity analysis allowing to identify the inlet data the most influential on the variability of the responses (residual stresses and distortions). Classically, the sensitivity analysis is carried out locally what limits its validity domain to a given material. A global sensitivity analysis method is proposed; it allows to cover a material domain as wide as those of the steels series. A probabilistic modeling giving the variability of the material parameters in the steels series is proposed. The original aspect of this work consists in the use of the sampling method by latin hypercubes (LHS) of the material parameters which forms the inlet data (dependent of temperature) of the numerical simulations. Thus, a statistical approach has been applied to the welding numerical simulation: LHS sampling of the material properties, global sensitivity analysis what has allowed the reduction of the material parameterization. (O.M.)

  17. The hardiness of numerical simulation of TIG welding. Application to stainless steel 316L structures; La robustesse de la simulation numerique du soudage TIG. Application sur des structures en acier 316L

    Energy Technology Data Exchange (ETDEWEB)

    El-Ahmar, Walid; Jullien, Jean-Francois [INSA-Lyon, LaMCoS, CNRS UMR 551, 20 Avenue Albert Einstein, 69621 Villeurbanne, (France); Gilles, Philippe [AREVA NP, 92084 Paris La Defense, (France); Taheri, Said [EDF, 92141 Clamart, (France); Boitout, Frederic [ESI-GROUP, 69458 Lyon, (France)

    2006-07-01

    The welding numerical simulation is considered as one of the mechanics problems the most un-linear on account of the great number of the parameters required. The analysis of the hardiness of the welding numerical simulation is a current questioning whose expectation is to specify welding numerical simulation procedures allowing to guarantee the reliability of the numerical result. In this work has been quantified the aspect 'uncertainties-sensitivity' imputable to different parameters which occur in the simulation of stainless steel 316L structures welded by the TIG process: that is to say the mechanical and thermophysical parameters, the types of modeling, the adopted behaviour laws, the modeling of the heat contribution.. (O.M.)

  18. Robustness of numerical TIG welding simulation of 3D structures in stainless steel 316L; Robustesse de la simulation numerique du soudage TIG de structures 3D en acier 316L

    Energy Technology Data Exchange (ETDEWEB)

    El-Ahmar, W

    2007-04-15

    The numerical welding simulation is considered to be one of those mechanical problems that have the great level of nonlinearity and which requires a good knowledge in various scientific fields. The 'Robustness Analysis' is a suitable tool to control the quality and guarantee the reliability of numerical welding results. The robustness of a numerical simulation of welding is related to the sensitivity of the modelling assumptions on the input parameters. A simulation is known as robust if the result that it produces is not very sensitive to uncertainties of the input data. The term 'Robust' was coined in statistics by G.E.P. Box in 1953. Various definitions of greater or lesser mathematical rigor are possible for the term, but in general, referring to a statistical estimator, it means 'insensitive to small deviation from the idealized assumptions for which the estimator is optimized. In order to evaluate the robustness of numerical welding simulation, sensitivity analyses on thermomechanical models and parameters have been conducted. At the first step, we research a reference solution which gives the best agreement with the thermal and mechanical experimental results. The second step consists in determining through numerical simulations which parameters have the largest influence on residual stresses induced by the welding process. The residual stresses were predicted using finite element method performed with Code-Aster of EDF and SYSWELD of ESI-GROUP. An analysis of robustness can prove to be heavy and expensive making it an unjustifiable route. However, only with development such tool of analysis can predictive methods become a useful tool for industry. (author)

  19. Design and realization of a fast digital system for the protection of a linear accelerator; Conception et realisation d'un systeme numerique rapide pour la protection d'un accelerateur lineaire

    Energy Technology Data Exchange (ETDEWEB)

    Hamdi, A

    2004-07-01

    The new generation of light sources based on SASE Free-Electron-Lasers driven by LINACs operate with electron beams with high beam currents and duty cycles. This is especially true for the superconducting machines like TTF 2 and the X-RAY FEL, under construction or planning at DESY. Elaborate fast protections systems are required not only to protect the machine from electron beams hitting and destroying the vacuum chamber, but also to prevent the machine from running at high loss levels, dangerous for components like the FEL undulator. This document presents the different protection systems currently under construction for TTF 2. The very fast systems, based on transmission measurements and distributed loss detection monitors, are described in detail. This description includes the fast electronics to collect and to transmit the different interlock and status signals: analog to digital converters, DSP and FPGA, interfaces, toroid protection system (TPS) card. The implementation and validation (simulation and tests) of the TPS card at DESY is presented.

  20. Numerical simulations of flows through fixed networks of monodispersed and bi-dispersed spheres, for moderate Reynolds numbers; Simulations numeriques d'ecoulements a travers des reseaux fixes de spheres monodisperses et bidisperses, pour des nombres de Reynolds moderes

    Energy Technology Data Exchange (ETDEWEB)

    Massol, A.

    2004-02-15

    The application of statistically averaged two-fluid models for the simulation of complex indus- trial two-phase flows requires the development of adequate models for the drag force exerted on the inclusions and the interfacial heat exchange. This task becomes problematic at high volume fractions of the dispersed phase. The quality of the simulation strongly depends upon the inter- facial exchange terms, starting with the steady drag force. For example, an accurate modelling of the drag force is therefore a crucial point to simulate the expansion of dense fluidized beds. Most models used to study the exchange terms between particles and fluids are based on the interaction between an isolated particle and a surrounding gas. Those models are clearly not adequate in cases where the volume fraction of particles increases and particle-particle interactions become important. Studying such cases is a complex task because of the multiple possible configurations. While the interaction between an isolated sphere and a gas depends only on the particle size and the slip velocity between gas and particles, the interaction between a cloud of particles and a gas depends on many more parameters: size and velocity distribution of particles, relative position of particles. Even if the particles keep relative fixed positions, there is an infinite number of combinations to construct such an array. The objective of the present work is to perform steady and unsteady simulations of the flow in regular arrays of fixed particles in order to analyze the influence of the size and distributions of spheres on drag force and heat transfer (the array of spheres can be either monodispersed, either bi-dispersed). Several authors have studied the drag exerted on the spheres, but only for low Reynolds numbers and/or solid volume fractions close to the packed limit. Moreover some discrepancies are observed between the different studies. On top of that, all existing studies are limited to steady flows, and do not deal with heat transfer and poly-dispersion. First of all, the steady viscous drag exerted on the spheres of face-centered cubic, simple cubic and tetragonal arrays is evaluated. This allows to analyze the influence of the spheres distribution and solid volume fraction on drag coefficient. Next, the influence of Reynolds number and solid volume fraction on heat transfer from spheres to the surrounding fluid in face-centered cubic arrays is studied. Finally, the history effects on the total force exerted on the inclusions and on the heat transfer between the inclusions and the surrounding fluid are studied. (author)