860 research outputs found

    The Knowledge of the Grid: A Grid Ontology

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    This paper presents a knowledge architecture and set of ontologies that can be used as the foundation to facilitate the matching of abstract resource requests to services and resources, to determine the functional equivalence of Grid middle wares and deployments and to allow the description of ‘hybrid’ compound Grids composed of individual heterogeneous Grids. This is necessary as in all these cases what is required is mediation between different views or descriptions of Grids, which requires a formal reference vocabulary. We present a framework and ontologies for achieving this

    Magnetic field dependence of hole levels in self-assembled InAs quantum dots

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    Recent magneto-transport experiments of holes in InGaAs quantum dots [D. Reuter, P. Kailuweit, A.D. Wieck, U. Zeitler, O. Wibbelhoff, C. Meier, A. Lorke, and J.C. Maan, Phys. Rev. Lett. 94, 026808 (2005)] are interpreted by employing a multi-band kp Hamiltonian, which considers the interaction between heavy hole and light hole subbands explicitely. No need of invoking an incomplete energy shell filling is required within this model. The crucial role we ascribe to the heavy hole-light hole interaction is further supported by one-band local-spin-density functional calculations, which show that Coulomb interactions do not induce any incomplete hole shell filling and therefore cannot account for the experimental magnetic field dispersion.Comment: 5 pages with 3 figures and one table. The paper has been submitted to Phys.Rev.

    Combining to innovate: A collaborative interprofessional learning approach to delivering Tobacco Use Prevention and Cessation (TUPAC) education for undergraduate oral health students

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    This paper provides a description of a pilot project in Tobacco Use Prevention and Cessation (TUPAC) in response to a national and international trend to include TUPAC curriculum components in the clinical education of undergraduate oral health students. In order to deliver quality brief intervention strategies for smokers a need to adequately prepare oral health students was identified during student clinical placements. An interprofessional (IP) project team was established with membership from the University of Adelaide’s School of Dentistry, QuitSA, Cancer Council SA, the South Australian Dental Service (SADS) Somerton Park and TAFESA’s Faculty of Dental Studies to streamline the efficient use of resources and most importantly draw on a diverse range of interprofessional health care expertise. On the website for The UK Centre for the Advancement of Interprofessional Education (CAIPE) (2002) it states that “Interprofessional education occurs when two or more professions learn from and about each other to improve collaboration and the quality of care”. Through interprofessional learning (IPL) in classroom and clinical settings, second year Bachelor and Advanced Diploma oral health students were provided with the opportunity to develop an understanding of the respective roles of each health professional responsible for delivering positive health initiatives in the area of TUPAC. With limited national oral health curricula in the area of TUPAC, the project team forged links with the University of Manitoba’s Dental Hygiene Program, and the convenor of the TUPAC in Dental and Dental Hygiene Undergraduate Education European Workshops for curriculum benchmarking against evidence based criteria. Most importantly as the IP concept of health care considers the patient at the centre of the health care team, assessment was designed to encourage a patient centred approach through the review and analysis of a clinical case study. A formal evaluation of this project is currently in progress, however results were not yet available at the time of publication

    Review of the Metropolitan Water Plan: Final Report

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    This report was commissioned by the NSW Cabinet Office to review the Metropolitan Water Plan 2004 (DIPNR, 2004a), and was undertaken by the Institute for Sustainable Futures at the University of Technology, Sydney and ACIL Tasman with technical advice from SMEC Australia. In February 2006, our interim review report (ISF, 2006) showed how the supply-demand balance in 2015 could be met with rain-fed supply and a suite of demand management initiatives, and how Sydneys water needs could be secured against the risk of severe drought by having the capacity to deploy groundwater and desalination

    Spin polarization and magneto-luminescence of confined electron-hole systems

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    A BCS-like variational wave-function, which is exact in the infinite field limit, is used to study the interplay among Zeeman energies, lateral confinement and particle correlations induced by the Coulomb interactions in strongly pumped neutral quantum dots. Band mixing effects are partially incorporated by means of field-dependent masses and g-factors. The spin polarization and the magneto-luminescence are computed as functions of the number of electron-hole pairs present in the dot and the applied magnetic field.Comment: To appear in Phys. Rev.

    The COMPTEL instrumental line background

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    The instrumental line background of the Compton telescope COMPTEL onboard the Compton Gamma-Ray Observatory is due to the activation and/or decay of many isotopes. The major components of this background can be attributed to eight individual isotopes, namely 2D, 22Na, 24Na, 28Al, 40K, 52Mn, 57Ni, and 208Tl. The identification of instrumental lines with specific isotopes is based on the line energies as well as on the variation of the event rate with time, cosmic-ray intensity, and deposited radiation dose during passages through the South-Atlantic Anomaly. The characteristic variation of the event rate due to a specific isotope depends on its life-time, orbital parameters such as the altitude of the satellite above Earth, and the solar cycle. A detailed understanding of the background contributions from instrumental lines is crucial at MeV energies for measuring the cosmic diffuse gamma-ray background and for observing gamma-ray line emission in the interstellar medium or from supernovae and their remnants. Procedures to determine the event rate from each background isotope are described, and their average activity in spacecraft materials over the first seven years of the mission is estimated.Comment: accepted for publication in A&A, 22 pages, 21 figure

    Data-Intensive architecture for scientific knowledge discovery

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    This paper presents a data-intensive architecture that demonstrates the ability to support applications from a wide range of application domains, and support the different types of users involved in defining, designing and executing data-intensive processing tasks. The prototype architecture is introduced, and the pivotal role of DISPEL as a canonical language is explained. The architecture promotes the exploration and exploitation of distributed and heterogeneous data and spans the complete knowledge discovery process, from data preparation, to analysis, to evaluation and reiteration. The architecture evaluation included large-scale applications from astronomy, cosmology, hydrology, functional genetics, imaging processing and seismology

    Dark-bright magneto-exciton mixing induced by Coulomb interaction in strained quantum wells

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    Coupled magneto-exciton states between allowed (`bright') and forbidden (`dark') transitions are found in absorption spectra of strained In0.2_{0.2}Ga0.8_{0.8}As/GaAs quantum wells with increasing magnetic field up to 30 T. We found large (~ 10 meV) energy splittings in the mixed states. The observed anticrossing behavior is independent of polarization, and sensitive only to the parity of the quantum confined states. Detailed experimental and theoretical investigations indicate that the excitonic Coulomb interaction rather than valence band complexity is responsible for the splittings. In addition, we determine the spin composition of the mixed states.Comment: 4 pages, 4 figure

    Parallel Magnetic Field Induced Transition in Transport in the Dilute Two-Dimensional Hole System in GaAs

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    A magnetic field applied parallel to the two-dimensional hole system in the GaAs/AlGaAs heterostructure, which is metallic in the absence of an external magnetic field, can drive the system into insulating at a finite field through a well defined transition. The value of resistivity at the transition is found to depend strongly on density

    Magnetic field dependence of the energy of negatively charged excitons in semiconductor quantum wells

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    A variational calculation of the spin-singlet and spin-triplet state of a negatively charged exciton (trion) confined to a single quantum well and in the presence of a perpendicular magnetic field is presented. We calculated the probability density and the pair correlation function of the singlet and triplet trion states. The dependence of the energy levels and of the binding energy on the well width and on the magnetic field strength was investigated. We compared our results with the available experimental data on GaAs/AlGaAs quantum wells and find that in the low magnetic field region (B<18 T) the observed transition are those of the singlet and the dark triplet trion (with angular momentum Lz=1L_z=-1), while for high magnetic fields (B>25 T) the dark trion becomes optically inactive and possibly a transition to a bright triplet trion (angular momentum Lz=0L_z=0) state is observed.Comment: 9 pages, 10 figures submitted to Phys. Rev.
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