Opacifiers in Late Bronze Age glasses: the use of ToF-SIMS to identify raw ingredients and production techniques

Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) is applied to the study of four samples of opaque glass of Late Bronze Age date. The technique is uniquely capable of identifying compositional heterogeneity at a sub-micron resolution within the crystalline opacifiers dispersed through homogeneous glass matrices. It is shown that this provides crucial information on the possible raw ingredients of the opacifying inclusions used, and has the potential for highlighting regional variations in the production technology involved in creating different colours of opaque glass.     

INTRODUCTION: PROCESSES OF CHANGE IN URBAN SYSTEMS*

ABSTRACT The twenty‐first century will be one of intensified urbanization, on a scale never before experienced. How do urban systems and individual cities change and develop? The social sciences have many different approaches to analyzing the economic, social, and spatial dimensions of urban change. We inventory some of these approaches and their implications for public policy toward cities, urban change, and economic development.     

Network Location and Policy‐Oriented Behavior: An Analysis of Two‐Mode Networks of Coauthored Documents Concerning Climate Change in the Great Lakes Region*,†

This study explores how a scientist's location in science‐based policy networks can affect her policy‐oriented behaviors. In particular, we hypothesize that those scientists who fill structural holes in their networks will be more likely than others to engage in policy‐oriented behaviors. The network data are defined by scientists' coauthorship on policy documents regarding climate change in the Great Lakes. We employ a two‐mode network analysis to identify clusters of scientists who coauthored similar documents, and relative to those clusters, we identify those who fill structural holes by bridging between clusters. We find that those scientists who bridged between clusters were more likely to engage in policy‐oriented behaviors of policy advocacy and advising than were others in the network. This is an example of a link between network location and policy‐oriented behavior indicative of the broader phenomenon of how individuals exert agency, given structural constraints.     

Transition in the use of cobalt-blue colorant in the New Kingdom of Egypt

Cobalt-blue colorant was first used in the 18th Dynasty in the New Kingdom of Egypt. The source of this cobalt was cobaltiferous alum from the Western Oases of Egypt. The use of this alum, especially in glass, was suddenly limited at the end of the 18th Dynasty. There is little evidence of the production of cobalt-blue glass in the Ramesside Period (the 19th–20th Dynasties) in the New Kingdom of Egypt. In this study, we brought a portable X-ray fluorescence spectrometer to two archaeological sites located in the Memphite region and used it for onsite analyses of Ramesside cobalt blue-colored glasses and faiences. This method revealed that the compositional characteristics of the cobalt-blue colorant in these Ramesside glasses and faiences is different from the colorant derived from cobaltiferous alum used in the 18th Dynasty, based on the comparison of transition metal composition and alumina content with those of the cobalt blue-colored artifacts from the 18th Dynasty. This result suggests that a new cobalt source other than cobaltiferous alum from the Western Oases was utilized in Egypt during the Ramesside Period.