Productive Relations in the Northeast and the Rest‐of‐Brazil Regions in 1995: Decomposition and Synergy in Input‐Output Systems

Using a set of interregional input‐output tables built by Guilhoto (1998) for 1995 for two Brazilian regions (Northeast and rest of the economy), the methodology developed by Sonis, Hewings, and Miyazawa (1997) is applied in the construction of a series of linkages such that it is possible to examine, through the nature of the internal and external interdependencies, the structure of trading relationships between the two regions. The methodology uses a partitioned input‐output system and exploits techniques that produce left and right matrix multipliers of the Leontief Inverse. This procedure facilitates the classification of the types of synergetic interactions within a preset pairwise hierarchy of economic linkages subsystems. In general, the results show that the Northeast region has a greater dependence on the rest of the economy region than the rest of the economy has on the Northeast region, and at the same time the rest of the economy region seems to be more developed as it presents a more complex productive structure than the Northeast region.     

The circulation of precious metals in the Arab Empire: the case of the near and the Middle East*

The analysis by nuclear activation techniques and by inductively coupled plasma mass spectrometry combined with an UV laser of a large number of gold coins issued in the Arab Empire from the seventh to the 12th century ad showed that several different supplying sources were used, according to the region and to the period. The aim of this paper is to point out the circulation of gold in the Near and Middle Eastern mints of the Arab Empire and to make a parallel with the mints’ policies running in the other regions of the Empire, such as North Africa, the Iberian Peninsula and the Sicily. The identification of different gold ores by means of characteristic trace elements indicated recycling of the ancient coinage and, after ad 750, the minting in the entire Arab Empire of different new gold ores: Egyptian type, North Eastern type and West African type. The analysis of a small number of silver coins from the same periods and regions also showed a change in the ore supply after ad 750.     

Equations of state for basin geofluids: algorithm review and intercomparison for brines

Physical properties of formation waters in sedimentary basins can vary by more than 25% for density and by one order of magnitude for viscosity. Density differences may enhance or retard flow driven by other mechanisms and can initiate buoyancy‐driven flow. For a given driving force, the flow rate and injectivity depend on viscosity and permeability. Thus, variations in the density and viscosity of formation waters may have or had a significant effect on the flow pattern in a sedimentary basin, with consequences for various basin processes. Therefore, it is critical to correctly estimate water properties at formation conditions for proper representation and interpretation of present flow systems, and for numerical simulations of basin evolution, hydrocarbon migration, ore genesis, and fate of injected fluids in sedimentary basins. Algorithms published over the years to calculate water density and viscosity as a function of temperature, pressure and salinity are based on empirical fitting of laboratory‐measured properties of predominantly NaCl solutions, but also field brines. A review and comparison of various algorithms are presented here, both in terms of applicability range and estimates of density and viscosity. The paucity of measured formation‐water properties at in situ conditions hinders a definitive conclusion regarding the validity of any of these algorithms. However, the comparison indicates the versatility of the various algorithms in various ranges of conditions found in sedimentary basins. The applicability of these algorithms to the density of formation waters in the Alberta Basin is also examined using a high‐quality database of 4854 water analyses. Consideration is also given to the percentage of cations that are heavier than Na in the waters.     

The Archaeology of War: A North American Perspective

This article reviews recent archaeological research on warfare in prestate societies of native North America. This survey comprises six regions: Arctic/Subarctic, Northwest Coast, California, Southwest/Great Basin, Great Plains, and Eastern Woodlands. Two lines of evidence, defensive settlement behavior and injuries in human skeletal remains, figure prominently in archaeological reconstructions of violence and warfare in these regions. Burning of sites and settlements also has been important for identifying the consequences of war and investigating more subtle aspects of strategy and directionality. Weaponry and iconography have to date provided important but more limited insights. Although considerable disparities exist between regions in the archaeological evidence for intra- and intergroup violence, all regions show a marked increase after A.D. 1000. These findings suggest that larger forces may have been responsible for escalating violence throughout North America at this time.     

Survey and excavation of the main well in Cape Town Castle, South Africa: fieldwork and structural aspects

During the last few decades, Cape Town Castle has been extensively renovated. Parallel to this, a series of archaeological excavations were undertaken under the auspices of different institutions. During the course of these, it became clear that one specific site needed to be approached in a rather unorthodox way. This site, the main well situated in the centre of the previous headquarters of the Dutch East India Company at the Cape of Good Hope, was filled with water. Owing to its inaccessibility and other constraints, which made the application of adapted excavation techniques necessary, the need arose to call in the assistance of a diver-archaeologist. This article describes the approach to fieldwork undertaken in the Kat well during 1989 and 1999 and some of this feature's structural details.     

Who Is the Enemy? The Nationalist Dilemma of Inclusion and Exclusion in Britain During the First World War

The First World War polarised British society. The British 'nation' needed a definition of the external enemy to generate internal cohesion as much as the production of modern hostility presupposed the existence of nationalism. Apparently, hostility which is nationalistically motivated is of functional importance for the cohesion of a society in war. But the construction of the nation along the lines of the dialectic structure of exclusion and inclusion implies that even its founding act encourages national splits. The manner in which nationalism generates social cohesion by excluding non-members at the same time always turns it into the expression of and the reason for internal conflicts. First and foremost, however, it was the co-existence of a whole host of concepts of the nation competing with each other for supremacy which turned nationalism into a disintegrative power in society. The co-existing national concepts by and large reflected the political factions and camps in the belligerent society. This article tries to outline the various ways in which the borderlines between the internal and the external enemy, between the hostile part of one's own society and a hostile foreign society converged under the circumstances of the exceptional burden of the First World War. At the end the hostility which was motivated and legitimised nationalistically both split and integrated British society.     

Gas breakthrough experiments on fine-grained sedimentary rocks

The capillary sealing efficiency of fine‐grained sedimentary rocks has been investigated by gas breakthrough experiments on fully water saturated claystones and siltstones (Boom Clay from Belgium, Opalinus Clay from Switzerland and Tertiary mudstone from offshore Norway) of different lithological compositions. Sand contents of the samples were consistently below 12%, major clay minerals were illite and smectite. Porosities determined by mercury injection lay between 10 and 30% while specific surface areas determined by nitrogen adsorption (BET method) ranged from 20 to 48 m² g ^{? 1}. Total organic carbon contents were below 2%. Prior to the gas breakthrough experiments the absolute (single phase) permeability (k_abs) of the samples was determined by steady state flow tests with water or NaCl brine. The k_abs values ranged between 3 and 550 nDarcy (3 × 10^?21 and 5.5 × 10^?19 m²). The maximum effective permeability to the gas‐phase (k_eff) measured after gas breakthrough on initially water‐saturated samples extended from 0.01 nDarcy (1 × 10^?23 m²) up to 1100 nDarcy (1.1 × 10^?18 m²). The residual differential pressures after re‐imbibition of the water phase, referred to as the ‘minimum capillary displacement pressures’ (P_d), ranged from 0.06 to 6.7 MPa. During the re‐imbibition process the effective permeability to the gas phase decreases with decreasing differential pressure. The recorded permeability/pressure data were used to derive the pore size distribution (mostly between 8 and 60 nm) and the transport porosity of the conducting pore system (10^‐5–10^‐2%). Correlations could be established between (i) absolute permeability coefficients and the maximum effective permeability coefficients and (ii) effective or absolute permeability coefficients and capillary sealing efficiency. No correlation was found between the capillary displacement pressures determined from gas breakthrough experiments and those derived theoretically by mercury injection.     

The significance of pockmarks to understanding fluid flow processes and geohazards

Underwater gas and liquid escape from the seafloor has long been treated as a mere curiosity. It was only after the advent of the side‐scan sonar and the subsequent discovery of pockmarks that the scale of fluid escape and the moon‐like terrain on parts of the ocean floor became generally known. Today, pockmarks ranging in size from the ‘unit pockmark’ (1–10 m wide, < 0.6 m deep) to the normal pockmark (10–700 m wide, up to 45 m deep) are known to occur in most seas, oceans, lakes and in many diverse geological settings. In addition to indicating areas of the seabed that are ‘hydraulically active’, pockmarks are known to occur on continental slopes with gas hydrates and in association with slides and slumps. However, possibly their potentially greatest significance is as an indicator of deep fluid pressure build‐up prior to earthquakes. Whereas only a few locations containing active (bubbling) pockmarks are known, those that become active a few days prior to major earthquakes may be important precursors that have been overlooked. Pockmark fields and individual pockmarks need to be instrumented with temperature and pressure sensors, and monitoring should continue over years. The scale of such research calls for a multinational project in several pockmark fields in various geological settings.