318 research outputs found
Minimal Ten-parameter Hermitian Texture Zeroes Mass Matrices and the CKM Matrix
Hermitian mass matrices for the up and down quarks with texture zeroes but
with the minimum number of parameters, ten, are investigated. We show how these
{\em minimum parameter} forms can be obtained from a general set of hermitian
matrices through weak basis transformations. For the most simple forms we show
that one can derive exact and compact parametrizations of the CKM mixing matrix
in terms of the elements of these mass matrices (and the quark masses).Comment: 14 pages.Talk given by M.B. at the MRST 98, ``Towards the Theory of
Everything", Montr\'eal, 13-15 May 199
Elevation of serum soluble E-selectin and VCAM-1 in severe asthma.
OBJECTIVE: To investigate the significance of circulating adhesion molecules associated with leucocyte-endothelial cell interactions in asthma, serum levels of soluble E (sE)-selectin, soluble P (sP)-selectin, soluble L (sL)-selectin, and soluble vascular cell adhesion molecule-1 (sVCAM-1) were measured in mild, moderate and severe asthma. METHOD: Serum levels of sE-selectin, sP-selectin, sL-selectin, and sVCAM-1 were measured in 32 women with asthma and 30 healthy donors using an enzyme-linked immunosorbent assay method. Twenty patients were suffering from severe asthma, and 12 from mild/moderate asthma. RESULTS: Serum sE-selectin and sVCAM-1 levels from patients with asthma were significantly higher than those observed in healthy donors (p < 0.01). The levels of sP-selectin were the same as those of controls. The level of sE-selectin exhibited an important increase in the severe asthmatic patients compared with mild/moderate asthma (p < 0.01). The sVCAM-1 level was increased in severe asthma when compared with healthy controls. There was no correlation between the levels of soluble selectins and the age of the patients. A significant correlation was found between sE-selectin and sVCAM-1 levels. CONCLUSION: These data indicate that circulating soluble forms of the selectins may have different kinetics during the clinical course of asthma, suggesting that they may reflect different inflammatory pathways in severe asthma. Both sVCAM-1 and sE-selectin may be useful immunological markers for monitoring disease activity in asthma
Patterns in the Fermion Mixing Matrix, a bottom-up approach
We first obtain the most general and compact parametrization of the unitary
transformation diagonalizing any 3 by 3 hermitian matrix H, as a function of
its elements and eigenvalues. We then study a special class of fermion mass
matrices, defined by the requirement that all of the diagonalizing unitary
matrices (in the up, down, charged lepton and neutrino sectors) contain at
least one mixing angle much smaller than the other two. Our new parametrization
allows us to quickly extract information on the patterns and predictions
emerging from this scheme. In particular we find that the phase difference
between two elements of the two mass matrices (of the sector in question)
controls the generic size of one of the observable fermion mixing angles: i.e.
just fixing that particular phase difference will "predict" the generic value
of one of the mixing angles, irrespective of the value of anything else.Comment: 29 pages, 3 figures, references added, to appear in PR
COMMANDE ET STABILITE DES SYSTEMES LINEAIRES FLOUS DE TAKAGI-SUGENO
Dans cet article, on présente un algorithme pour la conception d’un contrôleur linéaire stabilisant une classe desystèmes flous. Les systèmes en question sont du type Takagi-Sugeno, caractérisés par une représentationlinéaire du type x A x B u j j & = + . Cet algorithme exploite les modèles locaux du système, obtenus autour de pointsde fonctionnement et établis par l’expertise humaine sous la forme de règles de type IF-THEN. La mise en oeuvre del’algorithme exige la stabilité, au sens de Lyapunov, d’au moins un modèle local (Aj, Bj). L’algorithme ainsidéveloppé est appliqué à un robot manipulateur à un degré de liberté. Les simulations sont réalisées sousl’environnement MATLAB 5.3
Formation and Decay of Colour Centres in a Silicate Glasses Exposed to Gamma Radiation: Application to High-Dose Dosimetry
Uplifted supersymmetric Higgs region
We show that the parameter space of the Minimal Supersymmetric Standard Model
includes a region where the down-type fermion masses are generated by the
loop-induced couplings to the up-type Higgs doublet. In this region the
down-type Higgs doublet does not acquire a vacuum expectation value at tree
level, and has sizable couplings in the superpotential to the tau leptons and
bottom quarks. Besides a light standard-like Higgs boson, the Higgs spectrum
includes the nearly degenerate states of a heavy spin-0 doublet which can be
produced through their couplings to the quark and decay predominantly into
\tau^+\tau^- or \tau\nu.Comment: 14 pages; Signs in Eqns. (3.1) and (4.2) corrected, appendix include
Electrodynamics of Magnetic Pulse Welding Machines: Global and Local Electrical Analogues
In this paper, a theoretical, experimental and numerical study of MPW machines is carried
out. While it is known that such machines are very complex by nature because of the coupling
between different parts, we used simple electrical analogues to describe its dynamics. A RLC
circuit modeling the whole machine is depicted and experimental results are shown. A
further study including numerical simulations allows to compute the current distribution and
estimate the magnetic field within the coil but also the magnetic pressure generated in the
process, all using a 2D model and reasonable assumptions. A late theoretical study opens
the way for innovative experimental measurements regarding the kinetics of the
deformations of metallic tubes, but also their mechanical behavior before the welding
process, making use of their capacitive properties
La maladie de cowden a propos d’un cas
La maladie de Cowden est une maladie héréditaire à transmission autosomique dominante caractérisée par des lésions associant des atteintes cutanées constantes et caractéristiques (lésions papuleuses au niveau de la face et des extrémités) et des lésions viscérales inconstantes notamment thyroïdiennes, mammaires, intestinales et rénales à haut risque de dégénérescence. Nous rapportons un cas chez une femme de 30 ans porteuse d’une craniomégalie, de polypes intestinaux, d’un fibroadénome des seins, de lésions papuleuses des gencives et d’un goitre multi-nodulaire. Elle a eu dans notre service une thyroïdectomie totale dont l’analyse anatomopathologique définitive de la pièce a révélé un micro-carcinome vésiculaire du lobe gauche de la thyroïde. Les lésions thyroïdiennes sont habituellement bien limitées, mais devant la multifocalité, le risque accru de récidive et de dégénérescence maligne, une thyroïdectomie totale doit être préconisée.Mots clès : Maladie de Cowden, Cancer de la thyro
Association myélome multiple – maladie de Kaposi: à propos d’un cas
L'association Kaposi–myélome multiple est extrêmement rare. Nous rapportons, le cas d'un patient âgé de 76 ans suivi dans notre formation pour un myélome à immunoglobuline A kappa stade III-B selon Durie et Salmon. Ceci a été associé à des lésions cutanées dont la biopsie cutanée était en faveur d’une maladie de Kaposi. La sérologie de l’herpès virus humain de type 8 (HHV8) est revenue positive. Une radiothérapie sur les lésions était refusée par le patient. L'évolution était marquée par une altération de l'état général. Le patient ayant refusé la radiothérapie et toute prise en charge thérapeutique est décédée deux mois plus tard. Nous rapportons, à notre connaissance, le 18ème cas mondial de maladie de Kaposi associée à un Kahler chez un patient HHV8 positif. C'est une association exceptionnelle rendant probable le rôle pathogénique de HHV8 dans le développement du myélome
- …