Revealing the electronic band structure of trilayer graphene on SiC

Recently, a great deal of attention has been devoted to trilayer graphene because it displays stacking and electric-field–dependent electronic properties well-suited for electronic and photonic applications. Several theoretical studies have predicted the electronic dispersion of Bernal (ABA) and rhombohedral (ABC) stacked trilayers. However, a direct experimental visualization of a well-resolved band structure has not yet been reported. In this work, angle resolved photoemission spectroscopy data which show with high resolution the electronic band structure of trilayer graphene on 6H-SiC(0001) are presented. Electronic bands obtained from tight-binding calculations are fitted to the experimental data to extract the interatomic hopping parameters for Bernal and rhombohedral stacked trilayers. The presented results suggest that on SiC substrates the occurrence of rhombohedral stacked trilayer is significantly higher than in natural bulk graphite

Quasi-free Standing Epitaxial Graphene on SiC by Hydrogen Intercalation

Quasi-free standing epitaxial graphene is obtained on SiC(0001) by hydrogen intercalation. The hydrogen moves between the 6root3 reconstructed initial carbon layer and the SiC substrate. The topmost Si atoms which for epitaxial graphene are covalently bound to this buffer layer, are now saturated by hydrogen bonds. The buffer layer is turned into a quasi-free standing graphene monolayer with its typical linear pi-bands. Similarly, epitaxial monolayer graphene turns into a decoupled bilayer. The intercalation is stable in air and can be reversed by annealing to around 900 degrees Celsius.Comment: Accepted for publication in Physical Review Letter

Scaling limit for a drainage network model

We consider the two dimensional version of a drainage network model introduced by Gangopadhyay, Roy and Sarkar, and show that the appropriately rescaled family of its paths converges in distribution to the Brownian web. We do so by verifying the convergence criteria proposed by Fontes, Isopi, Newman and Ravishankar.Comment: 15 page

Neighbourhood branding and urban regeneration: performing the 'right to the brand' in Casilino, Rome

In the last decade, many cities have experimented with small-scale initiatives aimed at enhancing the quality of life of residents; these initiatives have somehow fostered a reconceptualization of the term, as well as practice, of urban regeneration. In this context, the role of civic networks in bringing forward experiments in the production of alternative imaginaries and place-making has gained a major role, in particular in marginal neighbourhoods. By focusing on a case study in the eastern periphery of Rome, the paper explores the case of citizen-led neighbourhood branding, highlighting open issues and ambiguities in claiming a 'right to the brand'

Perspectives en matière de croissance de la productivité et du PIB potentiel.

Compte rendu d’une conférence internationale, organisée en avril 2006 par la Banque de France et la Banque du Canada, visant à comparer les quantifications et diagnostics concernant les écarts de croissance de la productivité et du PIB potentiel des pays industrialisés.Croissance, croissance potentielle, productivité, institutions, réformes.

Introduction to the special issue: between practices and policies. Rethinking urban regeneration in Southern European cities after the crisis

This Special Issue explores new approaches to urban regeneration, and potentially give new meanings to the term itself, as it appears in the context of austerity urbanism. In particular, the aim of this Special Issue is to offer a Southern European perspective of the nexus between the withdrawal of the State from urban governance, and of the new forms of cooperation arising from civil society, thus presenting original research material, and innovative perspectives, for current debates in urban studies

Analysis of the seismic site effects along the ancient Via Laurentina (Rome)

This paper presents an evaluation of the Local Seismic Response (LSR) along the route of the ancient Roman road Via Laurentina, which has been exposed in several areas of southwest Rome over the last decade during the construction of new buildings and infrastructures. It is an example of LSR analysis applied to ancient and archaeological sites located in alluvial valleys with some methodological inferences for the design of infrastructure and urban planning. Since the ancient road does not cross the alluvial valley (namely the Fosso di Vallerano Valley) normal to its sides, it was not possible to directly perform 2D numerical modelling to evaluate the LSR along the road route. Therefore, outputs of 2D numerical models, obtained along three cross sections that were normal oriented respect to the valley, were projected along the route of the Via Laurentina within a reliable buffer attributed according to an available high-resolution geological model of the local subsoil. The modelled amplification functions consider physical effects due to both the 2D shape of the valley and the heterogeneities of the alluvial deposits. The 1D and 2D amplification functions were compared to output that non-negligible effects are related to the narrow shape of the fluvial valley and the lateral contacts between the lithotecnical units composing the alluvial fill. The here experienced methodology is suitable for applications to the numerical modelling of seismic response in case of linear infrastructures (i.e., roads, bridges, railways) that do not cross the natural system along physically characteristic directions (i.e. longitudinally or transversally)

The contribution of experimental archaeology in addressing the analysis of residues on spindle-whorls

This contribution focuses on residues developing on spindle-whorls during spinning. Such a kind of tools is largelydiffused in archaeological contexts where spindle-whorls were used in textile activities or deposited in burials asgrave goods. Scholars recently approached the analysis of these objects through experimental archaeology to betterunderstand their wide variation in size and shape especially in relationship with the adoption of specific spinningtechniques or the quality of the fibres processed for producing different kinds of yarn. The method presented herehighlights the contribution of controlled experiments to identify and to study the formation of organic deposits onspindle-whorls after repeated and intentional use. Moreover, this article provides a preliminary reference collectionof experimental residues combining different techniques of observation and different magnifications (Optical LightMicroscopes - OLM and Scanning Electron Microscope - SEM) on ceramic replicas to address the residuesinvestigation on textile tools in archaeological contexts.