Pigments, dyes, and black enamel—the colorants of reverse paintings on glass

Nondestructive analyses of medieval reverse paintings on glass revealed the same dyes and pigments customarily used in panel paintings. However, there is one exception: the black colorant is not a carbon-based pigment, but black enamel. In this respect, the stylistic as well as the technical influence of stained glass artwork can clearly be seen on reverse paintings on glass. However, there is a crucial difference: in reverse paintings, the black enamel is not fired onto the glass but painted (cold painting). Additional analyses confirmed these findings. Based on these results, the art form “reverse painting on glass” has technically to be characterized as a mixture of “stained glass” and “panel painting” that nonetheless develops into a genre of its own.     

The Italian Neolithic: A Synthesis of Research

This paper reviews the distinctive economic and social development of Neolithic Italy and its islands, from ca. 6000 B.C. until the emergence of the Copper Age ca. 3500 B.C. Through a synthesis of traditional interpretations and more recent discussions relating to early farming economies, social and technological developments, settlement, and landscape, the complex regional patterns are described. The development of archaeological studies in Italy, the biases in regional and chronological data collection, the regional patterns of cultures and landscapes, and the emergence of distinctive funerary, artistic and economic activities reveal a wealth of varied and intriguing archaeological information from a wide variety of sources that link parallel developments in the Mediterranean and Europe.     

The composition of late Romano-British colourless vessel glass: glass production and consumption

One hundred and twenty-eight colourless glass tablewares from settlement contexts throughout the British Isles, dating from the mid-3rd to 4th century AD, were analysed by ICP-AES spectrometry. Three distinct compositional groups were identified based upon the use of different decolourisers and primary raw materials, with possible sub-groups within these. These compositions have distinct, but overlapping chronological ranges, suggesting colourless glass production in at least three, possibly more, centres in the late Roman period. The compositional analysis highlights the high degree to which recycling of glass was taking place during this late period. The chronological distribution of some of these compositions is more restricted within the British assemblages than is observed in other published assemblages from Western Europe. This distinction may indicate different supply patterns of glass to the Western provinces.     

Headscarves,Judicial Activism,and Democracy: The 2007–8 Constitutional Crisis in Turkey

How are we to understand and analyse the constitutional tension in Turkey between the judiciary and the political sphere? In this article the issue is mirrored in the political crisis which started in April 2007 with the nomination of Abdullah Gül as presidential candidate by the moderate Islamist Justice and Development Party (AKP). The more detailed empirical background consists primarily of the dress code problematics including the matter of party closure. Theoretically, the “hegemonic preservation” thesis elaborated by Ran Hirschl turned out to be a useful instrument when it comes to explaining this political crisis as well as the origin of the so-called new constitutionalism. This is illustrated by the judicial activism in the headscarf affair as well as by the eagerness of the Republican People's Party (CHP), as the political representative of the secular establishment, to play the ‘Atatürk card’ and to submit the protection of their interest to an independent judiciary and not to the uncertainties of the mechanisms of majoritarian democracy. However, with regard to the current Turkish case my analysis also shows that Hirschl's thesis is too static and should be complemented with a more dynamic perspective of constitutional politics as a repeated game. One example of this is that even if the Turkish Constitutional Court (TCC) had declared the constitutional amendment on the headscarf invalid and voted for economic sanctions against the AKP, it did not close the party down.     

3D numerical modeling of hydrothermal processes during the lifetime of a deep geothermal reservoir

Understanding hydrothermal processes during production is critical to optimal geothermal reservoir management and sustainable utilization. This study addresses the hydrothermal (HT) processes in a geothermal research doublet consisting of the injection well E GrSk3/90 and production well Gt GrSk4/05 at the deep geothermal reservoir of Groß Schönebeck (north of Berlin, Germany) during geothermal power production. The reservoir is located between ?4050 to ?4250 m depth in the Lower Permian of the Northeast German Basin. Operational activities such as hydraulic stimulation, production (T = 150°C; Q = ?75 m³ h^?1; C = 265 g l^?1) and injection (T = 70°C; Q = 75 m³ h^?1; C = 265 g l^?1) change the HT conditions of the geothermal reservoir. The most significant changes affect temperature, mass concentration and pore pressure. These changes influence fluid density and viscosity as well as rock properties such as porosity, permeability, thermal conductivity and heat capacity. In addition, the geometry and hydraulic properties of hydraulically induced fractures vary during the lifetime of the reservoir. A three‐dimensional reservoir model was developed based on a structural geological model to simulate and understand the complex interaction of such processes. This model includes a full HT coupling of various petrophysical parameters. Specifically, temperature‐dependent thermal conductivity and heat capacity as well as the pressure‐, temperature‐ and mass concentration‐dependent fluid density and viscosity are considered. These parameters were determined by laboratory and field experiments. The effective pressure dependence of matrix permeability is less than 2.3% at our reservoir conditions and therefore can be neglected. The results of a three‐dimensional thermohaline finite‐element simulation of the life cycle performance of this geothermal well doublet indicate the beginning of thermal breakthrough after 3.6 years of utilization. This result is crucial for optimizing reservoir management. Geofluids (2010) 10 , 406–421     

Fruit and seed biomineralization and its effect on preservation

Mineralised fruits and seeds are frequently found in archaeological sediments but their chemical nature has not been often examined. The nature and the origin of these archaeobotanical remains have to be investigated to understand their taphonomic history. Fruits or seeds can be mineralised not only by replacement mineralisation but also by biomineralisation during the plant life. The mineral components of three fossil fruits sampled on the Pleistocene site of Dmanisi were analysed and compared with their modern analogues. Analyses were carried out by means of an environmental scanning electron microscope, equipped with an energy dispersive X-ray device and by means of a Fourier transform infrared spectrometer. Biogenic carbonates and/or biogenic silica were identified in the fossil and modern fruits of some taxa. Comparison between fossil and modern specimens has shown that molecular reorganisation occurred in carbonate and in biogenic silica during fossilisation, through diagenetic processes. The resulting stable mineral structures confer an exceptional preservation to fruits in sediments. Taking into account these taphonomic specificities (transformation and differential preservation), the chronological and palaeoenvironmental aspects of the mineralised fruits are discussed.