1,919 research outputs found

    QCD Sum Rules study of meson-baryon sigma terms

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    The pion-baryon sigma terms and the strange-quark condensates of the octet and the decuplet baryons are calculated by employing the method of quantum chromodynamics (QCD) sum rules. We evaluate the vacuum-to-vacuum transition matrix elements of two baryon interpolating fields in an external isoscalar-scalar field and use a Monte Carlo-based approach to systematically analyze the sum rules and the uncertainties in the results. We extract the ratios of the sigma terms, which have rather high accuracy and minimal dependence on QCD parameters. We discuss the sources of uncertainties and comment on possible strangeness content of the nucleon and the Delta.Comment: 17 pages, 10 figures, to be published in Phys. Rev.

    Quantal description of nucleon exchange in stochastic mean-field approach

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    Nucleon exchange mechanism is investigated in central collisions of symmetric heavy-ions in the basis of the stochastic mean-field approach. Quantal diffusion coefficients for nucleon exchange are calculated by including non-Markovian effects and shell structure. Variances of fragment mass distributions are calculated in central collisions of 40{}^{40}Ca + 40{}^{40}Ca, 48{}^{48}Ca + 48{}^{48}Ca and 56{}^{56}Ni + 56{}^{56}Ni systems

    Travels in Architectural History

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    "Travel": Special collection 2016-2017 for the EAHN open access journal, Architectural Histories. 10 original essays stemming from an international call for papers; all double-blind peer reviewed following a pre-selection. This Special Collection explores how travel, as a collective and individual practice, has been implicated in diverse architectural cultures across a wide range of periods and geographies. It offers new perspectives on the architect’s journey, examines representations of places by travellers, and considers the place of architecture within modern tourist itineraries and practices. Travel is a powerful force in shaping the perception of the modern world and plays an ever-growing role within architectural and urban cultures. Inextricably linked to political and ideological issues, travel redefines places and landscapes through new transport infrastructures and buildings. Architecture, in turn, is reconstructed through visual and textual narratives produced by scores of modern travellers – including writers and artists along with architects themselves. In the age of the camera, travel is bound up with new kinds of imaginaries; private records and recollections often mingle with official, stereotyped views, as the value of architectural heritage increasingly rests on the mechanical reproduction of its images. Whilst students often learn about architectural history through image collections, the place of the journey in the formation of the architect itself shifts. No longer a lone and passionate antiquarian or an itinerant designer, the modern architect eagerly hops on buses, trains and planes in pursuit of personal as well as professional interests. Increasingly built on a presumption of mobility, architectural culture integrates travel into cultural debates and design experiments. By addressing such issues from a variety of perspectives, this collection prompts us to rethink the mobile conditions in which architecture has historically been produced and received

    A sensitive and selective chemiluminogenic probe for palladium

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    Palladium triggered removal of a propargyl group leads to the cleavage of the 1,2-dioxetane ring, leading to bright chemiluminescence. The reaction of the probe is highly specific for the Pd species, thus the probe described here has considerable potential for practical utility. © The Royal Society of Chemistry.2015

    Three dimensional modeling via photographs for documentation of a village bath

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    24th International CIPA Symposium; Strasbourg; France; 2 September 2013 through 6 September 2013The aim of this study is supporting the conceptual discussions of architectural restoration with three dimensional modeling of monuments based on photogrammetric survey. In this study, a 16th century village bath in Ulamiş, Seferihisar, and Izmir is modeled for documentation. Ulamiş is one of the historical villages within which Turkish population first settled in the region of Seferihisar - Urla. The methodology was tested on an antique monument; a bath with a cubical form. Within the limits of this study, only the exterior of the bath was modeled. The presentation scale for the bath was determined as 1 / 50, considering the necessities of designing structural interventions and architectural ones within the scope of a restoration project. The three dimensional model produced is a realistic document presenting the present situation of the ruin. Traditional plan, elevation and perspective drawings may be produced from the model, in addition to the realistic textured renderings and wireframe representations. The model developed in this study provides opportunity for presenting photorealistic details of historical morphologies in scale. Compared to conventional drawings, the renders based on the 3d models provide an opportunity for conceiving architectural details such as color, material and texture. From these documents, relatively more detailed restitution hypothesis can be developed and intervention decisions can be taken. Finally, the principles derived from the case study can be used for 3d documentation of historical structures with irregular surfaces

    Comparison of Electron and Hole Charge-Discharge Dynamics in Germanium Nanocrystal Flash Memories

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    Cataloged from PDF version of article.Electron and hole charge and discharge dynamics are studied on plasma enhanced chemical vapor deposition grown metal-oxide-silicon germanium nanocrystal flash memory devices. Electron and hole charge and discharge currents are observed to differ significantly and depend on annealing conditions chosen for the formation of nanocrystals. At low annealing temperatures, holes are seen to charge slower but to escape faster than electrons. They discharge slower than electrons when annealing temperatures are raised. The results suggest that discharge currents are dominated by the interface layer acting as a quantum well for holes and by direct tunneling for elec-trons. (c) 2008 American Institute of Physics

    First record of the broad-banded cardinal fish Apogon fasciatus (White, 1790) from Turkey

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    Two specimens of the alien cardinal fish Apogon fasciatus (White, 1790) are recorded for the first time from Turkey and second time from the Mediterranean Sea. This is the fourth Indo-Pacific apogonid species documented in the Mediterranean Sea, and the introduction of this species to the eastern Mediterranean is due to migration from the Red Sea via the Suez Canal
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