Contribution of the Internal Field to the Anisotropic Optical Reflectance of GaP(110)

This article presents the theory of optical reflection from thin slabs of GaP(110) by means of the discrete dipole model and focusses especially upon the possible implications of this model for the surface induced optical anisotropy. The reflectance of a semi-infinite sample is extracted from slab calculations and compared with experiments. We find that the internal field has a very important role in determining the surface induced optical anisotropy. We also show that the surface sensitivity of such experiments can be estimated to be about five monolayer

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

Building on the Border: Architecture as a Meeting Place

To establish a border signifies defining a fixed point from which to start and to which to refer in order to circumscribe controlled and measured environments. It is not important whether it is a border between states and regions or private and public spaces, because the main effect of the border is to sanction a diversity. This proposal will analyse three case-studies that, starting from antiquity to the contemporary age, have proposed over time different ways of conceiving the border, making architecture the convergence point. The first is the Temple of Diana at Ephesus, a monument created by Greek artists located in Persian territory. It stood on the peninsula of Anatolia, the border land par excellence in the Hellenistic world, a place where the dominant Western cultures of Greece and Persia clashed. The second is Castel Velturno, a border utopia belonging to Prince-Bishop Cristoforo Madruzzo, who deposited his dreams of unification between the North and the South of Christianity which were torn apart by the theological demands addressed during the Council of Trento. Finally, this proposal will examine the contemporary project entitled the Bi-National Community Skyscraper, which proposes a reinterpretation of the walls erected on the border between the USA and Mexico by building a skyscraper on it in which the two communities can meet and merge together

Architectural Instructions in Italy between the 16th and 18th Centuries

Carlo Borromeo’s Instructions represent the only practical application of the Tridentine decrees in architecture. However, historians over time have given little weight to the work, which is mostly considered a simple parish handbook due to its practical-functional nature used to treat the sacred space. New research conducted on the literary work has focused on the massive diffusion of this treatise in the undergrowth of the ecclesiastical literature of the time, testifying to how much the Instructions are linked to the historical context and the spiritual needs of the post-Tridentine Church. The great novelty of the work lies in the fact that it completely overturned the way of writing about architecture. In the writings of Carlo Borromeo, a continuous interweaving between the doctrine of the soul and the sacred building is outlined to give the Church the image of an institution organically constituted in its material and spiritual reality. The influence of this work outside the Milanese context in which Carlo Borromeo worked is still to be clarified, especially in the South of Italy, which experienced the peak of its Counter-Reformation season between the seventeenth and eighteenth centuries. Here, Instructions will be analyzed along with the Antica Basilicografia of Pompeo Sarnelli (1686) and Il Rettore ecclesiastico of Marcello Cavalieri (1688), two writings born in the diocese of Benevento under the wing of the bishop Vincenzo Maria Orsini, a native of Gravina di Pugli

A Reflection on the Crisis of Public Monuments. The case of Historiated Column

The twentieth century generated a crisis of public monuments. This paper proposes a reflection on the choices made by society regarding what aspects of history to remember and how in order to provide a foundation for its collective identity. Since ancient times, the task of public monuments has been to imprint in history the perpetual memory of a character, identified as the ideal model around which the history of their time revolves. With the French Revolution, there was a fundamental change of course on this front. The public no longer needed to follow an ideal sovereign, and the story was no longer calibrated to a single character but to each citizen. The crisis of public monuments after World War II dealt with the concept of durability, a fundamental attribute for this archetype, with the consequent birth of the counter-monument. To fully understand this crisis, the evolution of one of the commemorative monuments par excellence – historiated column – will be analysed through three key examples, far apart in space and time, each exemplifying a precise evolutionary phase: Trajan’s Column, the Vendôme Column and the Monument against Fascism, War, Violence, erected in 1986 by Jochen and Ester Gerz

The Architectural Illusion of Edoardo Tresoldi: The Reconstruction of the Basilica of Siponto

The Ministry of Tourism commissioned Edoardo Tresoldi in 2016 to restore the Basilica of Siponto (Puglia, Italy), of which only ruins remain. The project is obtained through metal wefts that intertwine in the air presumably reconstructing the original environments: it is an example of creative restoration. This essay aims to examine the genesis of this artwork that has rekindled the debate on the usefulness of this type of restoration, introduced for the first time by Cesare Brandi (1906-1988) and Renato Bonelli (1911-2004) who gave rise to a critical discussion on the role that restoration must play in reconstructing the original spaces of a lost monument. Creative restoration tends to include in the concept of “restoration” all those actions of reconstruction necessary to restore “truth” to the lost monument in order to guarantee its enjoyment, making the “evocative fantasy” take over. Faced with an architecture that has now lost its face, the added value of Tresoldi’s creative restoration will be highlighted, which is not only the reconstruction of the Basilica but the possibility, through the wire mesh that generates transparency, to understand the monument not only as a historical document but as an artwork that needs to be experienced aesthetically, safeguarding the genius loci, making the site a place to be rediscovered in its link with the territory

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

Tort Law - Products Liability - Settlements - Contribution

The Pennsylvania Supreme Court found that a manufacturer was independently liable under products liability for the failure to warn of a known defect in a component part. The court also held that a settlement by one joint tort-feasor -reduced the verdict amount only by the settling defendant\u27s pro-rata share, and that the non-settling joint tort-feasor owed its full pro-rata share to the plaintiff. Walton v Avco Corp., ___ Pa ___ ,610 A2d 454 (1992)

Appellate Review in a Sentencing Guidelines Jurisdiction: The Pennsylvania Experience

This article reviews sentencing practices in Pennsylvania and the development of Sentencing Guidelines. It explores the emergence of appellate review of sentencing and how that has been affected by the interpretation of the Guideline legislation. It suggests changes to present practice that would permit and structure appellate review of sentencing

Ab initio study of reflectance anisotropy spectra of a sub-monolayer oxidized Si(100) surface

The effects of oxygen adsorption on the reflectance anisotropy spectrum (RAS) of reconstructed Si(100):O surfaces at sub-monolayer coverage (first stages of oxidation) have been studied by an ab initio DFT-LDA scheme within a plane-wave, norm-conserving pseudopotential approach. Dangling bonds and the main features of the characteristic RAS of the clean Si(100) surface are mostly preserved after oxidation of 50% of the surface dimers, with some visible changes: a small red shift of the first peak, and the appearance of a distinct spectral structure at about 1.5 eV. The electronic transitions involved in the latter have been analyzed through state-by-state and layer-by-layer decompositions of the RAS. We suggest that new interplay between present theoretical results and reflectance anisotropy spectroscopy experiments could lead to further clarification of structural and kinetic details of the Si(100) oxidation process in the sub-monolayer range.Comment: 21 pages, 8 figures. To be published in Physical Rev.