836 research outputs found

    Database independent Migration of Objects into an Object-Relational Database

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    This paper reports on the CERN-based WISDOM project which is studying the serialisation and deserialisation of data to/from an object database (objectivity) and ORACLE 9i.Comment: 26 pages, 18 figures; CMS CERN Conference Report cr02_01

    Hall plateaus at magic angles in bismuth beyond the quantum limit

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    We present a study of the angular dependence of the resistivity tensor up to 35 T in elemental bismuth complemented by torque magnetometry measurements in a similar configuration. For at least two particular field orientations a few degrees off the trigonal axis, the Hall resistivity was found to become field-independent within experimental resolution in a finite field window corresponding to a field which is roughly three times the frequency of quantum oscillations. The Hall plateaus rapidly vanish as the field is tilted off theses magic angles. We identify two distinct particularities of these specific orientations, which may play a role in the emergence of the Hall plateaus.Comment: 5 pages, 5 figure

    Heat transport in Bi_{2+x}Sr_{2-x}CuO_{6+\delta}: departure from the Wiedemann-Franz law in the vicinity of the metal-insulator transition

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    We present a study of heat transport in the cuprate superconductor Bi_{2+x}Sr_{2-x}CuO_{6+\delta} at subkelvin temperatures and in magnetic fields as high as 25T. In several samples with different doping levels close to optimal, the linear-temperature term of thermal conductivity was measured both at zero-field and in presence of a magnetic field strong enough to quench superconductivity. The zero-field data yields a superconducting gap of reasonable magnitude displaying a doping dependence similar to the one reported in other families of cuprate. The normal-state data together with the results of the resistivity measurements allows us to test the Wiedemann-Franz(WF) law, the validity of which was confirmed in an overdoped sample in agreement with previous studies. In contrast, a systematic deviation from the WF law was resolved for samples displaying either a lower doping content or a higher disorder. Thus, in the vicinity of the metal-insulator cross-over, heat conduction in the zero-temperature limit appears to become significantly larger than predicted by the WF law. Possible origins of this observation are discussed.Comment: 9 pages including 7 figures, submitted to Phys. Rev.

    An electronic instability in bismuth far beyond the quantum limit

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    We present a transport study of semi-metallic bismuth in presence of a magnetic field applied along the trigonal axis extended to 55 T for electric conductivity and to 45 T for thermoelectric response. The results uncover a new field scale at about 40 T in addition to the previously detected ones. Large anomalies in all transport properties point to an intriguing electronic instability deep in the ultraquantum regime. Unexpectedly, both the sheer magnitude of conductivity and its metallic temperature dependence are enhanced by this instability.Comment: 5 pages, 4 figure

    Hippocrates transformed: crafting a Hippocratic discourse of medical semiotics in English, 1850–1930

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    From Springer Nature via Jisc Publications RouterHistory: received 2019-12-11, accepted 2020-06-10, registration 2020-06-12, pub-electronic 2020-07-09, online 2020-07-09, collection 2020-12Publication status: PublishedAbstract: This study presents a methodology for adapting corpus linguistics to the genealogical analysis of translation’s role in the evolution of medical concepts. This methodology is exhibited by means of a case study that draws on a number of corpora to explore how two English translators—Francis Adams, a Scottish physician, and Williams H.S. Jones, a Cambridge philologist, classicist and ancient historian—translated a set of terms in Hippocratic medical texts that refer to how the body reveals illness. Drawing on the Genealogies of Knowledge subcorpora of ancient Greek and modern English, it examines some of the ways in which translation contributes to the creation of a Hippocratic semiotic discourse in English whose lexical features differ from those attested to in the subcorpus of Greek Hippocratic texts. A comparative analysis of keyword frequency and collocations of Greek semiotic terms such as sēmeion, and English terms such as sign and symptom reveals the different translation strategies Jones and Adams used to translate the text. The result of this process is a Hippocratic semiotic discourse in English whose lexical features do not reflect those in the Hippocratic texts in a straightforward way

    Laplace transformations of hydrodynamic type systems in Riemann invariants: periodic sequences

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    The conserved densities of hydrodynamic type system in Riemann invariants satisfy a system of linear second order partial differential equations. For linear systems of this type Darboux introduced Laplace transformations, generalising the classical transformations in the scalar case. It is demonstrated that Laplace transformations can be pulled back to the transformations of the corresponding hydrodynamic type systems. We discuss periodic Laplace sequences of with the emphasize on the simplest nontrivial case of period 2. For 3-component systems in Riemann invariants a complete discription of closed quadruples is proposed. They turn to be related to a special quadratic reduction of the (2+1)-dimensional 3-wave system which can be reduced to a triple of pairwize commuting Monge-Ampere equations. In terms of the Lame and rotation coefficients Laplace transformations have a natural interpretation as the symmetries of the Dirac operator, associated with the (2+1)-dimensional n-wave system. The 2-component Laplace transformations can be interpreted also as the symmetries of the (2+1)-dimensional integrable equations of Davey-Stewartson type. Laplace transformations of hydrodynamic type systems originate from a canonical geometric correspondence between systems of conservation laws and line congruences in projective space.Comment: 22 pages, Late

    Nernst effect in semi-metals: the meritorious heaviness of electrons

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    We present a study of electric, thermal and thermoelectric transport in elemental Bismuth, which presents a Nernst coefficient much larger than what was found in correlated metals. We argue that this is due to the combination of an exceptionally low carrier density with a very long electronic mean-free-path. The low thermomagnetic figure of merit is traced to the lightness of electrons. Heavy-electron semi-metals, which keep a metallic behavior in presence of a magnetic field, emerge as promising candidates for thermomagnetic cooling at low temperatures.Comment: 4 pages, including 4 figure

    Chiral symmetry breaking in QED3{\rm QED}_{3} in presence of irrelevant interactions: a renormalization group study

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    Motivated by recent theoretical approaches to high temperature superconductivity, we study dynamical mass generation in three dimensional quantum electrodynamics QED3{\rm QED}_{3}) in presence of irrelevant four-fermion quartic terms. The problem is reformulated in terms of the renormalization group flows of certain four-fermion couplings and charge, and then studied in the limit of large number of fermion flavors NN. We find that the critical number of fermions NcN_c below which the mass becomes dynamically generated depends continuously on a weak chiral-symmetry-breaking interaction. One-loop calculation in our gauge-invariant approach yields Nc0=6N_{c0} = 6 in pure QED3{\rm QED}_3. We also find that chiral-symmetry-preserving mass cannot become dynamically generated in pure QED3{\rm QED}_{3}.Comment: 7 pages, 7 figure
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