AFB(b) Status of Results

The status of results on forward-backward asymmetry in Z -> bbbar decays is reviewed. A comparison of LEP measurements, with emphasis on the final ALEPH measurement with leptons, and a critical discussion of average from heavy flavour electroweak combination is presented.Comment: 8 pages, 5 figures, to be published in Proceedings of "XXXVIIth Rencontres de Moriond - Electroweak Interactions and Unified Theories", Les Arcs, 9-16 March, 200

Studies of b-quark fragmentation

I will review new studies of b-quark fragmentation performed at the Z peak by ALEPH and SLD. An improved sensitivity to distinguish between fragmentation model and more accurate measurements of the mean b-hadron scaled energy have been obtained.Comment: 3 pages, 3 figures, presented at XXXth ICHEP, Osak

An integral equation method for the inverse conductivity problem

We present an image reconstruction algorithm for the Inverse Conductivity Problem based on reformulating the problem in terms of integral equations. We use as data the values of injected electric currents and of the corresponding induced boundary potentials, as well as the boundary values of the electrical conductivity. We have used a priori information to find a regularized conductivity distribution by first solving a Fredholm integral equation of the second kind for the Laplacian of the potential, and then by solving a first order partial differential equation for the regularized conductivity itself. Many of the calculations involved in the method can be achieved analytically using the eigenfunctions of an integral operator defined in the paper.Comment: 15 pages, 8 figure

Anomalous thresholds and edge singularities in Electrical Impedance Tomography

Studies of models of current flow behaviour in Electrical Impedance Tomography (EIT) have shown that the current density distribution varies extremely rapidly near the edge of the electrodes used in the technique. This behaviour imposes severe restrictions on the numerical techniques used in image reconstruction algorithms. In this paper we have considered a simple two dimensional case and we have shown how the theory of end point/pinch singularities which was developed for studying the anomalous thresholds encountered in elementary particle physics can be used to give a complete description of the analytic structure of the current density near to the edge of the electrodes. As a byproduct of this study it was possible to give a complete description of the Riemann sheet manifold of the eigenfunctions of the logarithmic kernel. These methods can be readily extended to other weakly singular kernels.Comment: Correction of a misprint which occurred in the unnumbered formula preceding Eq. (14), LaTeX file as an uuencoded file, 40 pages with 12 figures, uses epsf.st

On the possible implications of Dark Matter in the rings of Saturn: a conjecture

In this article we discuss some consequences of the well-known proposition of Fritz Zwicky [1], published in the nineteen thirties, that Dark Matter `mimics' the inertia-gravitational behaviour of usual matter. In particular, we consider some special dynamical regions such as those of the Ring Systems of the gaseous giants at the edge of the Planetary System. This article is a continuation of an earlier paper [2], where it was shown that gravitationally interacting particles may remain near the Lagrange Points L4 and L5 for many thousands of years. This provides enough time for the Dark Matter, if present there, to interact with the usual matter. We discuss also a number of questions related to places which might be considered singular in the mathematical sense.Comment: 14 pages, 9 figure

I Gesta Florentinorum di Sanzanome: una testimonianza significativa delle grandi imprese fiorentine tra gli anni '20 del sec. XII e gli anni '30 del sec. XIII

I Gesta Florentinorum di Sanzanome sono una testimonianza significativa delle grandi imprese fiorentine avvenute tra gli anni della conquista di Fiesole e gli anni '30 del sec. XIII. L'Autore, che inserisce orazioni e lettere ufficiali, vuole celebrare il primato di Firenze sotto ogni aspetto, anche quello dell'arte retorica. La cronaca conserva la memoria dei milites, protagonisti assoluti della vita politica fiorentina fino alle soglie degli anni '40 del Duecento. Sanzanome tiene a ricordare che sono stati proprio loro ad avere reso tanto grande Firenze

The CMS Silicon Strip Tracker: from integration to start-up

The CMS Silicon Strip Tracker (SST) integration has been completed. After an extensive period of testing with cosmic muons the detector is ready for the final installation inside the CMS magnet. This paper will review the integration procedures and the tests completed to ensure that SST performs according to specifications

Approximate 3-Dimensional Electrical Impedance Imaging

We discuss a new approach to three-dimensional electrical impedance imaging based on a reduction of the information to be demanded from a reconstruction algorithm. Images are obtained from a single measurement by suitably simplifying the geometry of the measuring chamber and by restricting the nature of the object to be imaged and the information required from the image. In particular we seek to establish the existence or non-existence of a single object (or a small number of objects) in a homogeneous background and the location of the former in the (x,y)-plane defined by the measuring electrodes. Given in addition the conductivity of the object rough estimates of its position along the z-axis may be obtained. The approach may have practical applications.Comment: 12 pages, 4 figures, LaTeX, Appendix added and other minor change

Thermal effects of different kind influencing lubricated non-conformal contacts

Three steel spherical specimens with different diameters are tested against a glass disc under the same working conditions in several rolling speeds and slide-to-roll ratios. The same tests are carried out with the specimens connected to a steel shaft with and without a ceramic insert purposely designed for limiting the transfer of the heat generated by the shaft seals and bearings to the specimens, in order to evaluate the influence of the experimental apparatus on friction results. A general increase in friction is found when the ceramic insert is used probably related to a greater local lubricant viscosity inside the contact due to the reduction in the specimen surface temperature. However, the configuration of the experimental apparatus does not influence in a significant way the shape of the friction curves as a function of the entraining speed and of the slide-to-roll ratio. The analysis of the interference images of the contact shows that the thermal insulation due to the ceramic insert does not affect particularly the film thickness