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991.
992.
Bruno E. J. S. Werz 《International Journal of Nautical Archaeology》2002,31(1):89-98
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. 相似文献
993.
Jérôme Wilson 《European Review of History》2002,9(2):223-239
La naissance de la Banque centrale européenne a suscité une discussion soutenue à propos des critères de convergence, de l'objectif d'inflation et de la flexibilitédes taux de change de l'euro par rapport aux autres monnaies-clés (dollar, yen). Un détour par les arrangements et unions/désunions monétaires passés s'avère pertinent en termes d'information à propos des conditions essentielles pour l'établissement et la gestion des politiques monétaires, non seulement du point de vue économique mais également du point de vue politique. Les lec¸ons principales qu'apporte l'Histoire indiquent que: inflation et taux de change constituent deux 'ancres', parmi d'autres, choisies en fonction d'une orientation idéologique plus marquée qu'il n'apparâ L t au premier abord; qu'àla fois les créditeurs et les débiteurs nets doivent être responsabilisés pour organiser un système durable; que l'intégration du marchéa toujours précédél'union monétaire; enfin, qu'un lien solide entre pays apporte une meilleure protection contre les chocs extérieurs qu'un ensemble de réactions individuelles non coordonnées. Néanmoins, une question importante reste en suspens: est-il possible pour une union monétaire de supporter la présence de parasites monétaires dans sa périphérie, hôtes indésirables qui ne participent pas au partage des coûts engendrés par l'union monétaire, mais qui s'invitent au sein du système et en profitent àtravers des alignements tacites sur la politique appliquée àla monnaie unique? 相似文献
994.
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. 相似文献
995.
The Devonian Antrim Shale is an organic‐rich, naturally fractured black shale in the Michigan Basin that serves as both a source and reservoir for natural gas. A well‐developed network of major, through‐going vertical fractures controls reservoir‐scale permeability in the Antrim Shale. Many fractures are open, but some are partially sealed by calcite cements that retain isotopic evidence of widespread microbial methanogenesis. Fracture filling calcite displays an unusually broad spectrum of δ13C values (+34 to ?41‰ PDB), suggesting that both aerobic and anaerobic bacterial processes were active in the reservoir. Calcites with high δ13C values (>+15‰) record cementation of fractures from dissolved inorganic carbon (DIC) generated during bacterial methanogenesis. Calcites with low δ13C values (32‰) are solely associated with outcrop samples and record methane oxidation during cement precipitation. Fracture‐fill calcite with δ13C values between ?10 and ?30‰ can be attributed to variable organic matter oxidation pathways, methane oxidation, and carbonate rock buffering. Identification of 13C‐rich calcite provides unambiguous evidence of biogenic methane generation and may be used to identify gas deposits in other sedimentary basins. It is likely that repeated glacial advances and retreats exposed the Antrim Shale at the basin margin, enhanced meteoric recharge into the shallow part of the fractured reservoir, and initiated multiple episodes of bacterial methanogenesis and methanotrophic activity that were recorded in fracture‐fill cements. The δ18O values in both formation waters and calcite cements increase with depth in the basin (?12 to ?4‰ SMOW, and +21 to +27‰ PDB, respectively). Most fracture‐fill cements from outcrop samples have δ13C values between ?41 and ?15‰ PDB. In contrast, most cement in cores have δ13C values between +15 and +34‰ PDB. Radiocarbon and 230Th dating of fracture‐fill calcite indicates that the calcite formed between 33 and 390 ka, well within the Pleistocene Epoch. 相似文献
996.
J. Emili Aura Tortosa V. Villaverde Bonilla M. Pérez Ripoll R. Martínez Valle P. Guillem Calatayud 《Journal of Archaeological Method and Theory》2002,9(3):215-268
This study analyzes the faunal assemblages corresponding to the Middle and Upper Paleolithic and the Early Epipaleolithic for the central Spanish Mediterranean Region dated from between 135,000 and 9,000 B.P. To interpret these data, we employ a zooarchaeological and paleoeconomic perspective. Human large and small game hunting systems are analyzed through the identification of the origins of faunal assemblages, bone breackage patterns, and prey selection patterns. Our study shows that hunting systems changed significantly through time, which may be related to the characteristics of the Mediterranean ecosystem and, above all, to cultural changes. 相似文献
997.
Field schools are a rite of passage for archaeologists, the first experience of what for many is the defining activity of the discipline: fieldwork. While teaching competence in practical techniques is the minimum goal of any field school, this technical training must be situated within the broader goals that drive the fieldwork. The University of Denver Archaeological Field School provides the fieldwork for the Colorado Coal Field War Archaeological Project. This project is an experiment in archaeology as political action in the present. It explores the possibility of an emancipatory archaeology through engagement with contemporary audiences and struggles. In this paper we discuss some of the ways we try to link technical training with the admittedly unusual theoretical and political goals of the project, teaching not only skills but an awareness of the responsibilities these skills should bring. 相似文献
998.
This article reviews the state of the two security and defence institutions available to west Europeans: NATO and the EU's common European Security and Defence Policy (ESDP). In each case, the authors assess the political maturity and stability of the institution, and then ask what it can contribute in terms of coordinated military capability to west European's strategic readiness. NATO's Prague summit in November 2002 will address the thorny issue of the next tranche of post–Cold War enlargement. But beyond the predictable debate about which candidates to admit, and what should be offered to those unsuccessful in their bid, there will be a far more urgent and important agenda to be discussed at Prague—the military capabilities of the European allies. Given that ESDP is still far from achieving its capability goals, the authors argue that the time is right for European allies to begin thinking in terms of generating a composite, joint strike force which could be configured to be interoperable with US forces and which could salvage something useful from the disheartening lack of progress in developing a European military capability. 相似文献
999.
On the Rank-Size Distribution for Human Settlements 总被引:9,自引:0,他引:9
William J. Reed 《Journal of regional science》2002,42(1):1-17
An explanation for the rank-size distribution for human settlements based on simple stochastic models of settlement formation and growth is presented. Not only does the analysis of the model explain the rank-size phenomenon in the upper tail, it also predicts a reverse rank-size phenomenon in the lower tail. Furthermore it yields a parametric form (the double Pareto-lognormal distribution) for the complete distribution of settlement sizes. Settlement-size data for four regions (two in Spain and two in the U.S.) are used as examples. For these regions the lower tail rank-size property is seen to hold and the double Pareto-lognormal distribution shown to provide an excellent fit, lending support to the model and to the explanation for the rank-size law. 相似文献
1000.