Hyper-Document structure: maintaining discourse coherence in non-linear documents

The passage from linear text to hypertext poses the challenge of expressing discourse coherence in non-linear text, where linguistic discourse markers no longer work. While hypertext introduces new possibilities for discourse organisation, it also requires the use of new devices which can support the expression of coherence by exploiting the technical characteristics and expressive capabilities of the medium. In this paper we show how in hypertext the notion of abstract document structure encompasses animated graphics as a form of meta-language for discourse construction

Demand for Money in the Asian Countries: A Systems GMM Panel Data Approach and Structural Breaks

A systems GMM method is used to estimate the demand for money (M1) for a panel of 11 Asian countries from 1970 to 2007. This method has advantages of which the most important one is its ability to minimise small sample bias with persistence in the variables. This system GMM method of Blundell and Bond (1998) simultaneously estimates specifications with the levels and first differences specifications of the variables. We test for structural stability of the estimated function with a recently developed test, for this approach, by Mancini-Griffoli and Pauwels (2006). Our results show that there is a well defined demand for money for these countries and there are no structural breaks.Systems GMM, Blundell and Bond, Mancini-Griffoli and Pauwels, Asian Countries and Demand for Money and Structural Sta

Study of the spin-32\frac32 Hubbard-Kondo lattice model by means of the Composite Operator Method

We study the spin-$\frac32$ Hubbard-Kondo lattice model by means of the Composite Operator Method, after applying a Holstein-Primakov transformation. The spin and particle dynamics in the ferromagnetic state are calculated by taking into account strong on-site correlations between electrons and antiferromagnetic exchange among $\frac32$ spins, together with usual Hund coupling between electrons and spins

Effects of two-site composite excitations in the Hubbard model

The electronic states of the Hubbard model are investigated by use of the Composite Operator Method. In addition to the Hubbard operators, two other operators related with two-site composite excitations are included in the basis. Within the present formulation, higher-order composite excitations are reduced to the chosen operatorial basis by means of a procedure preserving the particle-hole symmetry. The positive comparison with numerical simulations for the double occupancy indicates that such approximation improves over the two-pole approximation.Comment: 2 pages, 1 figur

Magnetic behavior of a spin-1 Blume-Emery-Griffiths model

I study the one-dimensional spin-1 Blume-Emery-Griffiths model with bilinear and biquadratic exchange interactions and single-ion crystal field under an applied magnetic field. This model can be exactly mapped into a tight-binding Hubbard model - extended to include intersite interactions - provided one renormalizes the chemical and the on-site potentials, which become temperature dependent. After this transformation, I provide the exact solution of the Blume-Emery-Griffiths model in one dimension by means of the Green's functions and equations of motion formalism. I investigate the magnetic variations of physical quantities - such as magnetization, quadrupolar moment, susceptibility - for different values of the interaction parameters and of the applied field, focusing on the role played by the biquadratic interaction in the breakdown of the magnetization plateaus.Comment: 4 pages, 5 figures. ICM 2009 (Karlsruhe) Conference proceeding

Passato e futuro nella scienza del suolo: la lezione di Fiorenzo Mancini.

I grandi uomini possono, attraverso il loro ricordo, suscitare nelle generazioni future la memoria dei grandi meriti e delle qualit\ue0 di cui sono stati portatori. \u201cQuindi trarrem gli auspici\u201d scriveva il Foscolo nel 1807. Noi oggi siamo qui, in questa magnifica Aula della Accademia dei Georgofili, per trarre gli auspici che il Professore Fiorenzo Mancini ha lasciato a tutti noi. La Societ\ue0 Italiana della Scienza del Suolo (SISS), ha avuto il Professore Mancini come socio fondatore, come Presidente (negli anni 1972-75) e, successivamente come Presidente Onorario. La SISS ha quindi accolto con autentico piacere l\u2019invito di patrocinare e di contribuire a questa giornata dedicata al Professore Fiorenzo Mancini e co-organizzata dalla Accademia dei Georgofili e dalla Accademia Italiana di Scienze Forestali

Features of the Extension of a Statistical Measure of Complexity to Continuous Systems

We discuss some aspects of the extension to continuous systems of a statistical measure of complexity introduced by Lopez-Ruiz, Mancini and Calbet (LMC) [Phys. Lett. A 209 (1995) 321]. In general, the extension of a magnitude from the discrete to the continuous case is not a trivial process and requires some choice. In the present study, several possibilities appear available. One of them is examined in detail. Some interesting properties desirable for any magnitude of complexity are discovered on this particular extension.Comment: 22 pages, 0 figure