3,986 research outputs found


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    In his monumental History of Economic Analysis, Joseph A. Schumpeter calls Serra “the first to compose a scientific treatise … on economic principles and policy.” This working paper, available only hardcopy and upon request, brings the first ever English translation of Antonio Serra’s Breve Trattato. However, the translation is designed to be used in a workshop to take place in Venice in 2007, sponsored by The Other Canon Foundation, which will produce a final English translation of the text for publication.

    Magnetic Thomas-Fermi-Weizs\"acker model for quantum dots: a comparison with Kohn-Sham ground states

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    The magnetic extension of the Thomas-Fermi-Weizs\"acker kinetic energy is used within density-functional-theory to numerically obtain the ground state densities and energies of two-dimensional quantum dots. The results are thoroughly compared with the microscopic Kohn-Sham ones in order to assess the validity of the semiclassical method. Circular as well as deformed systems are considered.Comment: EPJ LateX, revised EPJ-

    Magnetic dipole and electric quadrupole responses of elliptic quantum dots in magnetic fields

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    The magnetic dipole (M1) and electric quadupole (E2) responses of two-dimensional quantum dots with an elliptic shape are theoretically investigated as a function of the dot deformation and applied static magnetic field. Neglecting the electron-electron interaction we obtain analytical results which indicate the existence of four characteristic modes, with different BB-dispersion of their energies and associated strengths. Interaction effects are numerically studied within the time-dependent local-spin-density theory, assessing the validity of the non-interacting picture.Comment: 11 pages, 3 GIF figure

    Composizione biochimica di quattro specie fitoplanctoniche impiegate in acquicoltura

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    The protein, lipid, carbohydrate, and amino acid content of four algae of the genus Chlorella, Dunaliella, Nannochloris and Tetraselmis was determined: each species was grown on Walne's media containig two different levels of nitrogen. The results show how tbe media influenced the biochemical composition of the algae

    Electron spin precession in semiconductor quantum wires with Rashba spin-orbit coupling

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    The influence of the Rashba spin-orbit coupling on the electron spin dynamics is investigated for a ballistic semiconductor quantum wire with a finite width. We monitor the spin evolution using the time-dependent Schr\"odinger equation. The pure spin precession characteristic of the 1D limit is lost in a 2D wire with a finite lateral width. In general, the time evolution in the latter case is characterized by several frequencies and a nonrigid spin motion.Comment: 7 pages, 9 figure

    Collective oscillations in quantum rings: a broken symmetry case

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    We present calculations within density functional theory of the ground state and collective electronic oscillations in small two-dimensional quantum rings. No spatial symmetries are imposed to the solutions and, as in a recent contribution, a transition to a broken symmetry solution in the intrinsic reference frame for an increasingly narrow ring is found. The oscillations are addressed by using real-time simulation. Conspicuous effects of the broken symmetry solution on the spectra are pointed out.Comment: ReVTeX, 5 embedded eps, two gifs. Accepted in EPJ

    Il Presente e il futuro della legge sulle societĂ  in Italia

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    Nell’ordinamento italiano non si può parlare – come a tutti noto – di una legge sulle società di capitali, in quanto la disciplina di tali società è contenuta all’interno del sistema codicistico, che contempla sia le società personali sia le società di capitali. La distinzione, articolata per tipi di società (tre tipi di società personali a fronte di tre tipi di società di capitali) ed integrata dalla disciplina delle società mutualistiche e consortili, è stata confermata anche nella recente riforma del diritto societario italiano, la quale ha riguardato esclusivamente le società di capitali (società per azioni, società in accomandita per azioni e società a responsabilità limitata) e le società cooperative. Pertanto, in questa sede, si farà riferimento alle disposizioni della riforma (d.legvo 17 gennaio 2003, n. 6) per tracciare un quadro della disciplina vigente in Italia e delle sue prospettive, con espressa esclusione dell’esame relativo alla disciplina delle società con azioni quotate (d. leg.vo 24 febbraio 1998, n. 58) ed a quella delle cooperative
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