Melting of Iron

A theoretical melting curve for iron is determined in the pressure range of the Earth's core by a relation derived from the Ross-Lindemann melting criterium. On this basis the melting point of pure iron is estimated to be about 4800°C at the mantle-core boundary, and 6600°C at the inner core-outer core boundary with a melting point gradient of about 0-8 deglkm

Influence of shell structure on the equation of state of matter at high pressures*

We develop an equation of state of matter in the pressurerange of geophysical interest introducing shell structure in the Thomas-Fermi-Dirac atom model

On the Melting Curve at High Pressures

The asymptotic behaviour of the inclting curves for substances with closepacked structures is analysed by means of Monte Carlo caIculations on model systems of hard spheres. The Kraut--Kennedy melting law does not show the correct asymptotic behaviour. On this basis some recent results on the physics of the Earth's core are rejected

Low-Dimensional Spin Systems: Hidden Symmetries, Conformal Field Theories and Numerical Checks

We review here some general properties of antiferromagnetic Heisenberg spin chains, emphasizing and discussing the role of hidden symmetries in the classification of the various phases of the models. We present also some recent results that have been obtained with a combined use of Conformal Field Theory and of numerical Density Matrix Renormalization Group techniques.Comment: To be published in the proceedings of the XIII Conference on "Symmetries in Physics", held in Bregenz (Voralberg, Austria), 21-24/7/2003. Plain LaTeX2e, 4 EPS figure

On c=1c=1 critical phases in anisotropic spin-1 chains

Quantum spin-1 chains may develop massless phases in presence of Ising-like and single-ion anisotropies. We have studied c=1 critical phases by means of both analytical techniques, including a mapping of the lattice Hamiltonian onto an O(2) nonlinear sigma model, and a multi-target DMRG algorithm which allows for accurate calculation of excited states. We find excellent quantitative agreement with the theoretical predictions and conclude that a pure Gaussian model, without any orbifold construction, describes correctly the low-energy physics of these critical phases. This combined analysis indicates that the multicritical point at large single-ion anisotropy does not belong to the same universality class as the Takhtajan-Babujian Hamiltonian as claimed in the past. A link between string-order correlation functions and twisting vertex operators, along the c=1 line that ends at this point, is also suggested.Comment: 9 pages, 3 figures, svjour format, submitted to Eur. Phys. J.

Unsupervised analysis of small animal dynamic Cerenkov luminescence imaging

Clustering analysis (CA) and principal component analysis (PCA) were applied to dynamic Cerenkov lumi- nescence images (dCLI). In order to investigate the per- formances of the proposed approaches, two distinct dy- namic data sets obtained by injecting mice with 32 P-ATP and 18 F-FDG were acquired using the IVIS 200 optical im- ager. The k-means clustering algorithm has been applied to dCLI and was implemented using interactive data lan- guage 8.1. We show that cluster analysis allows us to ob- tain good agreement between the clustered and the corre- sponding emission regions like the bladder, the liver, and the tumor. We also show a good correspondence between the time activity curves of the different regions obtained by using CA and manual region of interest analysis on dCLIT and PCA images. We conclude that CA provides an auto- matic unsupervised method for the analysis of preclinical dynamic Cerenkov luminescence image data. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE). (DOI: 10.1117/1.3663442

Gauge/string duality and scalar glueball mass ratios

It has been shown by Polchinski and Strassler that the scaling of high energy QCD scattering amplitudes can be obtained from string theory. They considered an AdS slice as an approximation for the dual space of a confining gauge theory. Here we use this approximation to estimate in a very simple way the ratios of scalar glueball masses imposing Dirichlet boundary conditions on the string dilaton field. These ratios are in good agreement with the results in the literature. We also find that they do not depend on the size of the slice.Comment: 5 pages, no figures. References updated. Version published in JHE

Photodynamic therapy using Cerenkov and radioluminescence light

In this short review the potential use of Cerenkov radiation and radioluminescence as internal sources for Photodynamic therapy (PDT) is discussed. PDT has been developed over the course of more than 100 years and is based on the induced photo conversion of a drug called photosensitizer (PS) that triggers the production of cytotoxic reactive oxygen species (ROS) leading to the killing of the cells. In order to overcome the problem of light penetration in the tissues, different solutions were proposed in the past. The use of radioisotopes like: F-18, Cu-64, Y-90, Lu-177 as internal light sources increase the light fluence at the PS compared to an external source, resulting in a larger cytotoxic effect

Laser scanning the Garisenda and Asinelli towers in Bologna (Italy): detailed deformation patterns of two ancient leaning buildings

The Asinelli and Garisenda towers are the main symbol of the city of Bologna (Italy). These leaning towers, whose heights are about 97 m and 48 m respectively, were built during the early 12th century and are two of the few surviving ones from about a hundred tall medieval buildings that once characterized the city. Therefore, they are part of the Italian cultural heritage and their safeguard is extremely important. In order to evaluate in detail the deformations of these towers, in particular the deviations from a regular inclination of their walls, the terrestrial laser scanning (TLS) has been used and an efficient direct analysis method has been developed. The towers have been scanned from 6 viewpoints, providing 19 point clouds with a complete coverage of the visible surfaces with large overlap areas. For each tower, after the registration of the partial point clouds into a common reference frame, an accurate morphological analysis of the acquired surfaces has been carried out. The results show several zones affected by significant deformations and inclination changes. In the case of the Asinelli tower, for which a finite element model is available, the results have also been interpreted on the basis of the static load and normal modes. The correspondence between the measured deformation and the theoretically expected deformation, caused by a seismic sequence, is clear. This fact suggests a high sensibility of the tower to dynamic loads. Although a direct evaluation of the risk cannot be carried out with the obtained results, they lead to the general indication that the structural health of these buildings must be frequently checked and that man-made loads (e.g. vibration due to vehicular traffic) should be avoided or at least reduced