Comment to "Imaging the atomic orbitals of carbon atomic chains with field-emission electron microscopy"

The observation of a stable doublet pattern in the field-emission electron microscopy of a linear atomic chain requires a stable mechanism breaking the axial symmetry, which is not identified correctly by Mikhailovskij et al. [Phys. Rev. B 80, 165404 (2009)]. Using microscopic calculations, we attribute the observed pattern to the symmetry breaking produced by the ligand where the chain is attached, plus carbon pi-bonding alternation.Comment: 2 pages 1 fig, PRB commen

Surface versus crystal-termination effects in the optical properties of surfaces

We prove, by realistic microscopic calculations within the sp^3s^* Tight Binding method for GaAs (110) and (100), that the surface optical properties are not influenced by long-range crystal termination effects, and hence that they can be consistently studied considering slabs of limited thickness (20 - 30 \AA). The origin of derivative-like and bulk-like lineshapes in Reflection Anisotropy Spectra is also discussed, analyzing the effects arising from possible surface-induced reduction, broadening, and shifting of the bulk spectrum near the surface.Comment: 10 figures. In press in Physical Review B, scheduled 15 Aug. 199

Old and new Italian multinational firms

After a quick profile of Italian foreign direct investments since 1900 and a short review of the main explanations of the lagged multinational growth by Italian manufacturing companies, a quick glimpse of business histories is given to the only two still today living "old protagonists" (Pirelli, Fiat) and to three old corporate groups (Olivetti, SNIA Viscosa, Montecatini-Montedison) who had also reached a significant degree of full internationalization early in the XX century, but during the second postwar period underwent profound dismantling of their original business mission. Finally the paper focuses on few cases of "new protagonists", mid-size family companies who undertook a true multinational strategy only in the most recent decades and today represent the core of the Italian "fourth capitalism".Italian industry-multinational companies

Optical Properties of BN in the cubic and in the layered hexagonal phases

Linear optical functions of cubic and hexagonal BN have been studied within first principles DFT-LDA theory. Calculated energy-loss functions compare well with experiments and previous theoretical results both for h-BN and for c-BN. Discrepancies arise between theoretical results and experiments in the imaginary part of the dielectric function for c-BN. Possible explanation to this mismatch are proposed and evaluated; lattice constant variations, h-BN contamination in c-BN samples and self-energy effects.Comment: RevTex 42 pages, 16 postscript figures embedde

Ab initio calculation of excitonic effects in the optical spectra of semiconductors

An ab initio approach to the calculation of excitonic effects in the optical absorption spectra of semiconductors and insulators is formulated. It starts from a quasiparticle bandstructure calculation and is based on the relevant Bethe--Salpeter equation. An application to bulk silicon shows a substantial improvement with respect to previous calculations in the description of the experimental spectrum, for both peak positions and lineshape.Comment: 4 pages, 1 figur

Ab-initio calculation of the vibrational modes of SiH4, H2SiO, Si10H16, and Si10H14O

We have studied the normal modes of hydrogenated and oxidized silicon nanocrystals, namely SiH4 (silan), H2SiO (silanon), Si10H16 and Si10H14O. The small clusters (SiH4 and H2SiO) have been used for convergence tests and their bondlengths and frequencies have been compared with experimental and theoretical reference data. For the large clusters (Si10H16 and Si10H14O) we have investigated the vibrational density of states where we have identified the oxygen-related spectral features. The vibrational modes have been also analyzed with respect to the displacement patterns. The calculations have been carried out within the density-functional and density-functional perturbation theory using the local-density approximation.Comment: 9 pages, 7 figure

Factors affecting prognosis in myelofibrosis

Studies investigating factors affecting prognosis in primary myelofibrosis have been numerous over the years because of the high heterogeneity with regard to its natural clinical course. Recently, the increasing application of reduced-intensity conditioning with allogeneic hematopoietic stem cell transplantation as well as the ongoing rapid development of new experimental agents, such as JAK2 inhibitors, have made the requirement for simple and accurate scoring systems to select individual patients for the most appropriate treatment strategy even more critical. This short report summarizes the state of the art and the most recent advances in this area

[Resoconto sul] Seminario di studi <i>Il problema costituzionale della difesa dei diritti dei cittadini e il "modello" democratico-repubblicano romano (nel MMD anniversario della istituzione del tribunato della plebe)</i>, (Sassari, 17 novembre 2008)

Resoconto sul Seminario di studi Il problema costituzionale della difesa dei diritti dei cittadini e il "modello" democratico-repubblicano romano (nel MMD anniversario della istituzione del Tribunato della plebe), che si è svolto a Sassari il 17 novembre 2008, organizzato dal prof. Pietro Paolo Onida, con la segreteria scientifica della dott.ssa Cristiana M.A. Rinolfi, nell'ambito dell'attività didattica della cattedra di Istituzioni di diritto romano II dell'Università di Sassari

[Resoconto sul] 5. Seminario internazionale di studi <i>Tradizioni religiose e istituzioni giuridiche del popolo sardo: il culto di San Costantino imperatore tra Oriente e Occidente</i>, (Sassari-Sedilo, 4-6 luglio 2001)

Nei giorni 4-6 luglio 2001 si è svolto, a Sassari-Sedilo, sotto gli auspici della Regione Autonoma della Sardegna, il “V Seminario internazionale di studi” sul tema Tradizioni religiose e istituzioni giuridiche del popolo sardo: il culto di San Costantino imperatore tra Oriente e Occidente. Il "Seminario" è stato organizzato dal Dipartimento di Scienze giuridiche e dalla Facoltà di Giurisprudenza dell’Università di Sassari, nel quadro del Progetto strategico del Consiglio nazionale delle ricerche «I sistemi giuridici del Mediterraneo», coordinato dall’ISPROM-Istituto di studi e programmi per il Mediterraneo