Land-water linkages in rural watersheds: Results from the FAO electronic workshop

Resource /Energy Economics and Policy,

Effective potential approach to quantum dissipation in condensed matter systems

The effects of dissipation on the thermodynamic properties of nonlinear quantum systems are approached by the path-integral method in order to construct approximate classical-like formulas for evaluating thermal averages of thermodynamic quantities. Explicit calculations are presented for one-particle and many-body systems. The effects of the dissipation mechanism on the phase diagram of two-dimensional Josephson arrays is discussed.Comment: 7 pages, 5 figures, to appear in the Proceedings of Nonlinearity, Integrability And All That 20 Years After Needs 7

The quantum Heisenberg antiferromagnet on the square lattice

The pure-quantum self-consistent harmonic approximation, a semiclassical method based on the path-integral formulation of quantum statistical mechanics, is applied to the study of the thermodynamic behaviour of the quantum Heisenberg antiferromagnet on the square lattice (QHAF). Results for various properties are obtained for different values of the spin and successfully compared with experimental data.Comment: Proceedings of the Conference "Path Integrals from peV to TeV - 50 Years from Feynman's paper" (Florence, August 1998) -- 2 pages, ReVTeX, 2 figure

Las ciencias naturales y la exploración científica en Argentina a fines del siglo XIX

Este trabajo es un avance del estudio que realizo sobre la implantación de la ciencia europea del siglo XIX en Argentina En particular abarco el caso de las ciencias naturales en Córdoba a fines de la centuria mencionada

Dispersion managed mode-locking dynamics in a Ti:Sapphire laser

We present what is to our knowledge the most complete 1-D numerical analysis of the evolution and the propagation dynamics of an ultrashort laser pulse in a Ti:Sapphire laser oscillator. This study confirms the dispersion managed model of mode-locking, and emphasizes the role of the Kerr nonlinearity in generating mode-locked spectra with a smooth and well-behaved spectral phase. A very good agreement with preliminary experimental measurements is found.Comment: 11 pages, 4 figures, submitted to Optics Letter

Il ruolo della Sardegna nel commercio mediterraneo del Quattrocento. Alcune considerazioni sulla base di fonti toscane

Sulla scorta di una documentazione conservata negli archivi toscani (libri aziendali e protocolli notarili fiorentini, registri doganali pisani) il saggio mira a indagare le rotte e i traffici mercantili che interessarono la Sardegna nel XV secolo. Pur in questa ottica relativamente parziale, si evidenziano alcune linee di inversione di tendenza rispetto alla catastrofica situazione demografica ed economico-sociale determinatasi in seguito alle pestilenze e allo stato prolungato di guerra tra catalano-aragonesi e guidici di Arborea

Uomini d’affari e mobilità sociale in Italia tra metà Trecento e primo Cinquecento

Il saggio esamina il peso esercitato dagli uomini d’affari nei processi di mobilità socio-economica e socio-politica avvenuti nell’Italia delle città tra la metà del XIV e l’inizio del XVI secolo. Il contributo, basato in larga misura sui risultati più innovativi della più recente storiografia, ha l’obiettivo di modificare la tradizionale visione del tardo Medioevo italiano, come un’età caratterizzata dal tramonto del dinamismo imprenditoriale e dal riemergere di modelli sociali basati sulla preminenza aristocratica. Sarà dunque evidente come il modello di tanti governi oligarchici urbani sia una realtà più tarda, maturata nella piena età moderna.This essay examines the role played by businessmen in the socio-economic and socio-political mobility of Italian cities between the mid-fourteenth and the beginning of the sixteenth centuries. This paper, based largely on the most innovative results of recent historiography, aims to modify the traditional view of the late Italian Middle Ages as an era characterized by the decline of entrepreneurial dynamism and the re-emergence of social models based on aristocratic prominence. It becomes evident that the model of the urban oligarchic governments is a later reality matured in the modern period