Archaeometric investigation of Roman tesserae from Herculaneum (Italy) by the combined use of complementary micro-destructive analytical techniques

Vitreous tesserae from two mosaics in Herculaneum (Italy) dating from the 1st century AD have been investigated in order to gather information on Imperial Age opaque glass. The combined use of complementary micro-destructive analytical techniques, namely optical microscopy (OM), scanning electron microscopy (SEM) with energy dispersive spectrometry (EDS), inductively coupled plasma-mass spectrometry (ICP-MS), transmission electron microscopy (TEM), and X-ray powder diffraction (XRPD) allowed to define the nature of formers, fluxes, chromophores and opacifying compounds and to determine the type of raw materials employed for their introduction. The results confirmed the high technological level of Imperial Age glassmakers and clarified some details of the production processes. Experimental data have been obtained concerning formation of antimony-based opacifiers. The presence of tin-containing Ca- and Pb-antimonates has been ascertained in various green, yellow and turquoise tesserae. Moreover, unusual divergences from the established Roman age ‘low magnesia–low potash’ (LMLK) glass composition have been found for some red and green samples.     

Geometry,Construction and Structural Analysis of the Crossed-Arch Vault of the Chapel of Villaviciosa,in the Mosque of Córdoba

The vault of Villaviciosa is one of the oldest existing examples of a true ribbed vault, and is the first of the crossed-arch type. Although its perfection suggests earlier trials, none has been found so far. It predates the oldest Romanesque ribbed vaults by more than a century. Notwithstanding its importance, no construction and structural study has ever been done; neither has an accurate survey been published. The purpose of this article is to fill this gap in the history of vault construction. A detailed survey has been made, providing the first accurate drawings of the vault. A close inspection of the extrados, completed with a visual inspection of interior damages, has allowed ascertaining the main construction features. With the geometry and the material data a structural analysis has been carried out. This analysis explains the fundamental structural behavior of the vault and throws new light into some historical issues; for example, it leads to discarding the widespread belief that the ribs are decorative: they are supporting the weight of the vault.     

Power and Historical Figuring: Rachael Pringle Polgreen's Troubled Archive

Rachael Pringle Polgreen, a freed‘mulatto’ woman who owned an infamous brothel/hotel in Bridgetown, Barbados during the 1770s and 1780s became known to her contemporaries through her role in the (sexual) entertainment of transient naval officers and the visits of Prince William of England. Piecing together ‘evidence’ from her will, estate inventory, a nineteenth‐century novel, a lithograph and an interview with a British officer, I engage Polgreen's complicated and fragmented archive, revealing how Polgreen represents an example of the problems with sources depicting women of African descent who lived in a slave society and the silences that inundate their archive. The first part of this article critically re‐examines pieces of her archive, through which an image of Polgreen emerges incommensurable with narratives of her triumphs. Next, through an analysis of the processes by which Polgreen is historically confined by powerful archival and subsequent historical representations, I challenge previous assumptions about her life. Finally, introducing material from the British parliamentary debates in which an incident involving Polgreen is described and new material from Barbados deeds left by Polgreen's former slave, I expose the nuances of Polgreen's ‘agency’ in a slave society – that which depended upon her sexual subjugation of other women of African descent.     

Overlapping rivalries: the two Germanys,Israel and the Cold War

The case of early German-Israeli relations offers unique insight into the dynamics of the German Cold War. As this article shows, the two Germanys were ideologically and geopolitically antithetical, but vis-a-vis the question of relations with Israel East and West German representatives faced a situation that was uniquely related to the German past and to the German Cold War competition.     

Electrochemical Characterization and Dating of Archaeological Leaded Bronze Objects Using the Voltammetry of Immobilized Particles

The application of solid state electrochemistry techniques for the characterization and dating of leaded bronze objects is described. Characteristic voltammetric signatures of copper and lead corrosion products were used as markers of more or less prolonged corrosion periods. The proposed methodology was applied to samples from the Roman archaeological sites of Valeria (Spain) and Gadara (Jordan), Roman and medieval sites in Xàtiva (Spain), and modern statuary exhibited outdoors, on the campus of the Universitat Politècnica of Valencia, Spain, covering a time interval between the fourth to second century bc and the 20th century ad . For such samples, the ratio between the signals for copper and lead corrosion products decreased monotonically with the corrosion time. This variation was modelled on the basis of thermochemical and kinetic considerations, the experimental data being consistent with a potential rate law for the corrosion process.     

The struggle for reform: contested conceptualizations of iṣlāḥ in the Maghreb*

This contribution draws an historical and conceptual analysis of the concept of i?lā?, which is traditionally understood as “reform” in general terms, and tries to stress the origins and the main conceptual paradigms of the two main ideological and political lines in which this concept has been developed and is still used in the Arab Maghreb by main political actors and thinkers.     

Exploring chronic arsenic poisoning in pre-Columbian Chilean mummies

This paper explores to what extent arsenic poisoning affected pre-Columbian northern Chile populations living between Arica and Iquique cities. We hypothesize, the pre-Columbian inhabitants of this region, will show arseniasis according to modern geographic endemic levels. Continuous exposure to high levels of arsenic causes serious health problems. Today, in the Camarones valley, where many Chinchorro people lived, arsenic levels are 100 times above the 10 μg/L recommended by the World Health Organization (WHO). Using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) we determined arsenic levels in a single strand of hair of 45 Arica mummies coming from ten sites (Morro 1, Morro 1/5, Yungay 372, Camarones 8, 9, 15D, and 17 and Azapa 140, Sermenia and Patillos), ranging from Chinchorro (ca. 5000–2000 years B.C.) to the Late Intermediate Period (1000–1400 years A.D.). Each hair was cleaned using distilled ionized water and placed on double sided mounting tape and ablated using a 266 nm Nd-YAG UV laser. Hair samples were also investigated for potential diagenesis.     

A Constructive Genetic Algorithm for Discrete Dispersion on Point Feature Cartographic Label Placement Problems

This article concerns the point feature cartographic label placement (PFCLP) problem, which is a NP‐hard (Non‐deterministic Polynomial‐time hard) combinatorial problem. It is considered that when all points must be labeled and overlaps are inevitable, the map can be more readable if overlapping labels are placed in a dispersive way, that is, overlapping labels are distant from each other. This work presents a constructive genetic algorithm (CGA) for the discrete dispersion PFCLP that utilizes the notion of masking to preserve optimal subsequences in chromosomes. We also define the discrete dispersion PFCLP as a mixed integer linear programming model, considering the problem of the minimum number of labels in conflict as well. The computational results validate our CGA approach using instances up to 5,046 points.