25,073 research outputs found
Linear and field-independent relation between vortex core state energy and gap in Bi2Sr2CaCu2O8+d
We present a scanning tunneling spectroscopy study on quasiparticle states in vortex cores in Bi2Sr2CaCu2O8+Ī“. The energy of the observed vortex core states shows an approximately linear scaling with the superconducting gap in the region just outside the core. This clearly distinguishes them from conventional localized core states and is a signature of the mechanism responsible for their discrete appearance in high-temperature superconductors. The energy scaling of the vortex core states also suggests a common nature of vortex cores in Bi2Sr2CaCu2O8+Ī“ and YBa2Cu3O7-Ī“. Finally, these states do not show any dependence on the applied magnetic field between 1 and 6 T
Belovode: past, present and future
The 2012 and 2013 excavations and subsequent post- excavation analyses by The Rise of Metallurgy in Eurasia project team at the site of Belovode built upon two decades of earlier work led by the National Museum of Belgrade and the Museum in Požarevac (JacanoviÄ and Å ljivar 2003; Å ljivar 2006; Å ljivar and JacanoviÄ 1996b, 1996c, 1997c; Å ljivar et al. 2006). This earlier work across 17 trenches had identified four building horizons (Belovode AāD), the presence of the entire VinÄa culture ceramic sequence from VinÄa TordoÅ” (AāB1) to the Gradac Phase (IāIII) as well as stone tools, figurines, obsidian blades, animal bone and, most importantly for the current research, evidence for the smelting of copper ores. As detailed in Chapter 5, it was the archaeometallurgical analysis of five small copper slags from Trench 3 together with the radiocarbon dating of the excavated horizon in which they were found that provided evidence for copper smelting at c. 5000 BC (RadivojeviÄ et al. 2010a) and the foundation for The Rise of Metallurgy in Eurasia project. However, in the absence of any detailed publication on these earlier excavations at Belovode, further questions relating to broader context of the earliest evidence for copper smelting could not be explored
Balkan metallurgy in a Eurasian context
As outlined in Chapter 2, three key lines of enquiry shaped The Rise of Metallurgy in Eurasia project and underpinned the research questions. Firstly, there are competing views about whether metallurgy in Eurasia had a single origin or arose in multiple places. There are also different perspectives regarding the ways in which pre-existing technical knowledge influenced and inspired the emergence of this new technology. Further discourse relates to the manner in which this early metallurgy was organised across the chaƮne opƩratoire of metal production and use and developed across a range of metals and alloys. Each of these three themes are fundamental to early metallurgy across the world (see papers in Roberts and Thornton 2014). These are areas of investigation with a deep history of scholarship and a wide range of competing explanatory models
Balkan metallurgy and society, 6200ā3700 BC
This chapter reviews the pre-existing evidence and interpretations for early mineral use and metallurgy in the Balkans from the earliest use of copper minerals at c. 6200 BC (Late Mesolithic-Early Neolithic) to c. 3700 BC (end of the Chalcolithic). It presents the empirical and intellectual foundations upon which the data, analyses and interpretations of The Rise of Metallurgy in Eurasia project builds. The early metallurgy in this region encompasses the production, distribution and consumption of copper, gold, bronze, lead and silver, all being either pure metals or a natural alloy (tin bronze)1. The chapter initially defines the geographical and temporal scope under consideration before evaluating the archaeological and metallurgical evidence in relation to: mineral exploitation; mining; smelting, metals and metal artefacts; and metal circulation. Following each of these sub-sections is a summary of how The Rise of Metallurgy in Eurasia project oughtto contribute to this aspect of metallurgical activity, setting this in relation to the projectās six research questions as presented in Chapter 2. The chapter concludes by highlighting the dominant interpretative narratives relating to early metallurgy, metallurgists and societies in the Balkans that The Rise of Metallurgy in Eurasia project will evaluate, against all the available and relevant archaeological and metallurgical data
The VinÄa culture: an overview
This chapter reviews the archaeological evidence for the VinÄa culture, the broader archaeological context for the majority of the metal production and metal artefacts extensively explored in Chapter 3, as well as for the sites of Belovode and PloÄnik, whose investigation forms the core of The Rise of Metallurgy in Eurasia project. The chapter will provide a lengthy introduction to the current data and interpretations of the VinÄa culture that are subsequently developed in far greater detail in the thematic overviews by many of the leading specialists in later chapters (Chapters 39ā52). This monograph seeks to address, at least in part, the absence of a dedicated synthesis of the VinÄa culture since Chapmanās (1981) monograph (see Chapman 2020b for a critical reflection).
The concept of archaeological cultures remains problematic in European prehistory in terms of definition and interpretation, yet extremely resilient in the absence of comparable empirically orientated alternatives (Roberts and Vander Linden 2011). Due to competing national traditions of scholarship, the culture history groupings and terminologies are strikingly complex in the later prehistoric Balkans (Gori and Ivanova 2017; Tsirtsoni 2016a). As such, the chapter explores the historiography and complex debates that surround the archaeological and temporal definitions of the VinÄa culture. The importance of the VinÄa culture lies not only in the evidence of early metallurgy but also in the evidence for the expansion of material culture production and circulation, the intensification of agriculture and increase in sedentism and settlement growth, which are all subsequently reviewed. The chapter concludes by examining past and present interpretations of the communities who lived and died within what we now term the VinÄa culture
Liver Transplantation in Adults
Human liver transplantation has been possible since 1967. We report our experience in 32 adult patients who received liver transplants at the University of Pittsburgh over a 16āmonth period. Survival data, method utilized for patient selection, costs, and morbidity of the procedure are discussed. Copyright Ā© 1982 American Association for the Study of Liver Disease
Relative and absolute chronologies of Belovode and PloÄnik
The chronology of the sites of Belovode and PloÄnik has been discussed several times in the past two decades since excavations were renewed at each site (ArsenijeviÄ and ŽivkoviÄ 1998; Å ljivar 1996; Å ljivar and JacanoviÄ 1996a; Å ljivar and KuzmanoviÄ CvetkoviÄ 1997a), though not in detail and rarely integrating the relative and the absolute chronological sequences. Chronologies from both sites have been published (Whittle et al. 2016), drawing upon eight radiocarbon dates from the two trenches then existing for Belovode (Trenches 7 and 8) and nine radiocarbon dates from three trenches for PloÄnik (Trenches 14, 15 and 16). These dates were allegedly focussing on the dating of metallurgical finds, however, the nature of those finds was not known at the time, so the best guess was to date materials from the spits, which only adds to the doubt on the chronological precision achieved.
The seriation and ceramic sequences of both sites resulting from this project are discussed in detail elsewhere in this volume (see Chapters 12, 13, 27 and 28) and in this chapter will be used only to illustrate relative chronology compared to other chronologies used for VinÄa culture (see Chapter 4). The identical spit and context excavation methodology employed on both sites enables us to compare chronologically sensitive pottery forms to other relevant sites of the period. This chapter presents 29 new radiocarbon dates from throughout the excavated sequences: 17 from Trench 18 at Belovode and 12 from Trench 24 at PloÄnik. The systematic excavations, relative ceramic sequences and the intensity of radiocarbon dating enables a far more precise modelling of dates for the identifiable activity horizons at both sites
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