7,567 research outputs found

    Using an ontology for interoperability and browsing of museum, library and archive information

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    Ontologies play an important part in the development of the future ‘semantic web’; the CIDOC conceptual reference model (CRM) is an ontology aimed at the cultural heritage domain. This paper describes a Concept Browser, developed for the EU/IST-funded SCULPTEUR project (semantic and content-based multimedia exploitation for European benefit environment (programme IST-2001-no. 35372); May 2002 to May 2005), which is able to access different museum information systems through a common ontology, the CRM. The development of this Concept Browser has required mappings from the legacy museum database systems to the CRM. The crucial process of creating the mappings is described, using the C2RMF catalogue (EROS) and library databases as a case study

    Spectroscopy, Equation Of State And Monopole Percolation In Lattice QED With Two Flavors

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    Non-compact lattice QED with two flavors of light dynamical quarks is simulated on 16416^4 lattices, and the chiral condensate, monopole density and susceptibility and the meson masses are measured. Data from relatively high statistics runs at relatively small bare fermion masses of 0.005, 0.01, 0.02 and 0.03 (lattice units) are presented. Three independent methods of data analysis indicate that the critical point occurs at β=0.225(5)\beta =0.225(5) and that the monopole condensation and chiral symmetry breaking transitions are coincident. The monopole condensation data satisfies finite size scaling hypotheses with critical indices compatible with four dimensional percolation. The best chiral equation of state fit produces critical exponents (δ=2.31\delta=2.31, βmag=0.763\beta_{mag}=0.763) which deviate significantly from mean field expectations. Data for the ratio of the sigma to pion masses produces an estimate of the critical index δ\delta in good agreement with chiral condensate measurements. In the strong coupling phase the ratio of the meson masses are Mσ2/Mρ20.35M_\sigma^2/M_\rho^2\approx 0.35, MA12/Mρ21.4M_{A_1}^2/M_\rho^2\approx 1.4 and Mπ2/Mρ20.0M_\pi^2/M_\rho^2\approx 0.0, while on the weak coupling side of the transition Mπ2/Mρ21.0M_\pi^2/M_\rho^2\approx 1.0, MA12/Mρ21.0M_{A_1}^2/M_\rho^2\approx 1.0, indicating the restoration of chiral symmetry.\footnote{\,^{}}{August 1992}Comment: 21 pages, 24 figures (not included

    Spin correlations and velocity-scaling in color-octet NRQCD matrix elements

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    We compute spin-dependent decay matrix elements for S-wave charmonium and bottomonium in lattice nonrelativistic quantum chromodynamics (NRQCD). Particular emphasis is placed upon the color-octet matrix elements, since the corresponding production matrix elements are expected to appear in the dominant contributions to the production cross sections at large transverse momenta. We use three slightly different versions of the heavy-quark lattice Green's functions in order to minimize the contributions that scale as powers of the ultraviolet cutoff. The lattice matrix elements that we calculate obey the hierarchy that is suggested by the velocity-scaling rules of NRQCD.Comment: 25 pages, 2 figures, 2 tables, further discussion of effective lattice cutoffs and uncertainties, additional minor revisions, version to be published in Phys. Rev.

    Neutron capture rates and r-process nucleosynthesis

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    Simulations of r-process nucleosynthesis require nuclear physics information for thousands of neutron-rich nuclear species from the line of stability to the neutron drip line. While arguably the most important pieces of nuclear data for the r-process are the masses and beta decay rates, individual neutron capture rates can also be of key importance in setting the final r-process abundance pattern. Here we consider the influence of neutron capture rates in forming the A~80 and rare earth peaks.Comment: 10 pages, 5 figures, appears in the Proceedings of the 14th International Symposium on Capture Gamma-Ray Spectroscopy and Related Topic

    Persistent Decadal-Scale Rainfall Variability in the Tropical South Pacific Convergence Zone Through the Past Six Centuries

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    Modern Pacific decadal variability (PDV) has global impacts; hence records of PDV from the pre-instrumental period are needed to better inform models that are used to project future climate variability. We focus here on reconstructing rainfall in the western tropical Pacific (Solomon Islands; similar to 9.5 degrees S, similar to 160 degrees E), a region directly influenced by PDV, using cave deposits (stalagmite). A relationship is developed between delta O-18 variations in the stalagmite and local rainfall amount to produce a 600 yr record of rainfall variability from the South Pacific Convergence Zone (SPCZ). We present evidence for large (similar to 1.5 m), abrupt, and periodic changes in total annual rainfall amount on decadal to multidecadal timescales since 1423 +/- 5 CE (Common Era) in the Solomon Islands. The timing of the decadal changes in rainfall inferred from the 20th-century portion of the stalagmite delta O-18 record coincides with previously identified decadal shifts in PDV-related Pacific ocean-atmosphere behavior (Clement et al., 2011; Deser et al., 2004). The Solomons record of PDV is not associated with variations in external forcings, but rather results from internal climate variability. The 600 yr Solomon Islands stalagmite delta O-18 record indicates that decadal oscillations in rainfall are a persistent characteristic of SPCZ-related climate variability.Taiwan ROC NSCNTU 101-2116-M-002-009, 102-2116-M-002-016, 101R7625Geological Science

    Virtues and risks of poverty

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    The article discusses the disadvantaged of a not-for-profit organisation having a surplus of financial accounts in seeking financial support from donors and funders in New Zealand. It states that to ensure financial accounts do not show a surplus, not-for-profit organisations separate some profitable activities into a separate organisation that are not included in consolidation. It emphasizes that separation of surplus can be useful for not-for-profits having large portion of restricted surplus

    A Random Matrix Study of the QCD Sign Problem

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    We investigate the severity of the sign problem in a random matrix model for QCD at finite temperature T and baryon chemical potential mu. We obtain analytic expression for the average phase factor -- the measure of the severity of the sign problem at arbitrary T and mu. We observe that the sign problem becomes less severe as the temperature is increased. We also find the domain where the sign problem is maximal -- the average phase factor is zero, which is related to the pion condensation phase in the QCD with finite isospin chemical potential. We find that, in the matrix model we studied, the critical point is located inside the domain of the maximal sign problem, making the point inaccessible to conventional reweighting techniques. We observe and describe the scaling behavior of the size and shape of the pion condensation near the chiral limit.Comment: 16 pages, 3 figure

    Random polynomials, random matrices, and LL-functions

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    We show that the Circular Orthogonal Ensemble of random matrices arises naturally from a family of random polynomials. This sheds light on the appearance of random matrix statistics in the zeros of the Riemann zeta-function.Comment: Added background material. Final version. To appear in Nonlinearit

    Entanglement between more than two hundred macroscopic atomic ensembles in a solid

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    We create a multi-partite entangled state by storing a single photon in a crystal that contains many large atomic ensembles with distinct resonance frequencies. The photon is re-emitted at a well-defined time due to an interference effect analogous to multi-slit diffraction. We derive a lower bound for the number of entangled ensembles based on the contrast of the interference and the single-photon character of the input, and we experimentally demonstrate entanglement between over two hundred ensembles, each containing a billion atoms. In addition, we illustrate the fact that each individual ensemble contains further entanglement. Our results are the first demonstration of entanglement between many macroscopic systems in a solid and open the door to creating even more complex entangled states.Comment: 10 pages, 8 figures; see also parallel submission by Frowis et a

    The influence of barefoot and barefoot inspired footwear on the kinetics and kinematics of running in comparison to conventional running shoes.

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    Barefoot running has experienced a resurgence in footwear biomechanics literature, based on the supposition that it serves to reduce the occurrence of overuse injuries in comparison to conventional shoe models. This consensus has lead footwear manufacturers to develop shoes which aim to mimic the mechanics of barefoot locomotion. This study compared the impact kinetics and 3-D joint angular kinematics observed whilst running: barefoot, in conventional cushioned running shoes and in shoes designed to integrate the perceived benefits of barefoot locomotion. The aim of the current investigation was therefore to determine whether differences in impact kinetics exist between the footwear conditions and whether shoes which aim to simulate barefoot movement patterns can closely mimic the 3-D kinematics of barefoot running. Twelve participants ran at 4.0 m.s-1±5% in each footwear condition. Angular joint kinematics from the hip, knee and ankle in the sagittal, coronal and transverse planes were measured using an eight camera motion analysis system. In addition simultaneous tibial acceleration and ground reaction forces were obtained. Impact parameters and joint kinematics were subsequently compared using repeated measures ANOVAs. The kinematic analysis indicates that in comparison to the conventional and barefoot inspired shoes that running barefoot was associated significantly greater plantar-flexion at footstrike and range of motion to peak dorsiflexion. Furthermore, the kinetic analysis revealed that compared to the conventional footwear impact parameters were significantly greater in the barefoot condition. Therefore this study suggests that barefoot running is associated with impact kinetics linked to an increased risk of overuse injury, when compared to conventional shod running. Furthermore, the mechanics of the shoes which aim to simulate barefoot movement patterns do not appear to closely mimic the kinematics of barefoot locomotion
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