73,808 research outputs found

    Aiming for ultra-scalable ePortfolio distribution using peer-to-peer networks

    Get PDF
    In this paper the authors discuss how peer-to-peer technology offers a practical solution to building highly scalable Europe-wide and worldwide ePortfolio networks over existing network infrastructures.This solution also offers the effect of empowering individuals through moving the management and storage responsibilities onto the portfolio owners, decoupling users from any single institutional ePortfolio service provider The authors do not present this solution as the single way forward, but as an alternative to what is seen as a mainly client-server and Web-based approach to ePortfolio development, and to encourage developers to explore the possibilities for ePortfolio integration with emerging and relatively immature technologies. A prototype implementation is reported and future developments described

    Harnessing mobile technology for classroom learning

    No full text
    Educational institutions are reluctant adopt mobile computing and Wireless technologies. This is because this technology remains relatively expensive compared to traditional computing technologies, mobile devices are inherently personal and can be difficult to use as a teaching tool to groups of learners, and Short Message Services and Multimedia Message Services (SMS/MMS) are expensive and limited in functional scope despite their popularity amongst young people. In this paper, we describe a component of a prototype learning environment named Quest where we propose anew way of harnessing mobile technology for learning that negates these drawbacks. In Quest we have demonstrated that the information gathering capabilities of mobile phones can be harnessed to aid learners research

    Ensemble Density Functional Theory for Inhomogeneous Fractional Quantum Hall Systems

    Full text link
    The fractional quantum Hall effect (FQHE) occurs at certain magnetic field strengths B*(n) in a two-dimensional electron gas of density n at strong magnetic fields perpendicular to the plane of the electron gas. At these magnetic fields strengths, the system is incompressible, i.e., there is a finite cost in energy for creating charge density fluctuations in the bulk, while the boundary of the electron gas has gapless modes of density waves. The bulk energy gap arises because of the strong electron-electron interactions. While there are very good models for infinite homogeneous systems and for the gapless excitations of the boundary of the electron gas, computational methods to accurately model finite, inhomogeneous systems with more then about ten electrons have not been available until very recently. We will here review an ensemble density functional approach to studying the ground state of large inhomogeneous spin polarized FQHE systems.Comment: 23 pages (revtex), 6 Postscript figures. To be published in Int. J. Quant. Chem. (invited talk at the 1996 Sanibel Symposium

    Properties from relativistic coupled-cluster without truncation: hyperfine constants of 25Mg+^{25}{\rm Mg}^+, 43Ca+^{43}{\rm Ca}^+ , 87Sr+^{87}{\rm Sr}^+ and 137Ba+^{137}{\rm Ba}^+

    Full text link
    We demonstrate an iterative scheme for coupled-cluster properties calculations without truncating the dressed properties operator. For validation, magnetic dipole hyperfine constants of alkaline Earth ions are calculated with relativistic coupled-cluster and role of electron correlation examined. Then, a detailed analysis of the higher order terms is carried out. Based on the results, we arrive at an optimal form of the dressed operator. Which we recommend for properties calculations with relativistic coupled-cluster theory.Comment: 13 pages, 4 figures, 5 table

    The conversation: developing confidence to provide end of life care in Salford nursing homes

    Get PDF
    The study was funded by the Burdett Trust for Nursing and partly by Salford Primary Care Trust. A realistic evaluation design was used to collect data using a range of approaches, from before and after surveys of confidence in delivering end of life care, to participant observation and interviews. A total of 43 people were interviewed involving both staff, residents and relatives. Key Messages a) Significant resources are needed to engage staff, residents and relatives/carers with the idea of advance care planning b) Care home staff are optimistic about involving residents and relatives in planning care at the end of life and some relatives become very involved in care c) Clearly registered nurses and other care home workers such as care assistants have different roles, but the overlap between these and the appropriate boundaries would benefit from further work d) Talking to residents and relatives about their feelings and wishes for care at the end of life remains especially difficult, but education and training in key skills and knowledge can engender both ability and motivation e) Care homes need strong and well-informed leadership in order to implement the Gold Standards Framework f) Placing a relative in a care home involves strain and an ability to compromise ‘there’s no perfect place’ g) Advance care planning can reduce the distress and the number of inappropriate hospital admissions, but is challenging in the face of staff rotation and out of hours medical staff being unpredictable h) The principles of the Gold Standards Framework are widely seen as sensible, but clinical challenges include diagnosing and predicting dying trajectories, especially in heart failure, chronic pulmonary disease and dementia i) A particular concern of staff is how to approach nutrition and hydration as frailty and death approach j) Communicating about diagnosis and especially prognosis with residents who lack capacity is an increasing problem k) Natural justice suggests that resources should be allocated to the general standardisation of a good quality of care at the end of life in ALL care homes whatever their Care Quality Commission ratin

    Structural Properties and Relative Stability of (Meta)Stable Ordered, Partially-ordered and Disordered Al-Li Alloy Phases

    Get PDF
    We resolve issues that have plagued reliable prediction of relative phase stability for solid-solutions and compounds. Due to its commercially important phase diagram, we showcase Al-Li system because historically density-functional theory (DFT) results show large scatter and limited success in predicting the structural properties and stability of solid-solutions relative to ordered compounds. Using recent advances in an optimal basis-set representation of the topology of electronic charge density (and, hence, atomic size), we present DFT results that agree reasonably well with all known experimental data for the structural properties and formation energies of ordered, off-stoichiometric partially-ordered and disordered alloys, opening the way for reliable study in complex alloys.Comment: 7 pages, 2 figures, 2 Table

    A new proof that alternating links are non-trivial

    Full text link
    We use a simple geometric argument and small cancellation properties of link groups to prove that alternating links are non-trivial. This proof uses only classic results in topology and combinatorial group theory.Comment: Minor changes. To appear in Fundamenta Mathematica

    EffiTest: Efficient Delay Test and Statistical Prediction for Configuring Post-silicon Tunable Buffers

    Full text link
    At nanometer manufacturing technology nodes, process variations significantly affect circuit performance. To combat them, post- silicon clock tuning buffers can be deployed to balance timing bud- gets of critical paths for each individual chip after manufacturing. The challenge of this method is that path delays should be mea- sured for each chip to configure the tuning buffers properly. Current methods for this delay measurement rely on path-wise frequency stepping. This strategy, however, requires too much time from ex- pensive testers. In this paper, we propose an efficient delay test framework (EffiTest) to solve the post-silicon testing problem by aligning path delays using the already-existing tuning buffers in the circuit. In addition, we only test representative paths and the delays of other paths are estimated by statistical delay prediction. Exper- imental results demonstrate that the proposed method can reduce the number of frequency stepping iterations by more than 94% with only a slight yield loss.Comment: ACM/IEEE Design Automation Conference (DAC), June 201

    The Hidden Spatial Geometry of Non-Abelian Gauge Theories

    Full text link
    The Gauss law constraint in the Hamiltonian form of the SU(2)SU(2) gauge theory of gluons is satisfied by any functional of the gauge invariant tensor variable ϕij=BiaBja\phi^{ij} = B^{ia} B^{ja}. Arguments are given that the tensor Gij=(ϕ1)ijdetBG_{ij} = (\phi^{-1})_{ij}\,\det B is a more appropriate variable. When the Hamiltonian is expressed in terms of ϕ\phi or GG, the quantity Γjki\Gamma^i_{jk} appears. The gauge field Bianchi and Ricci identities yield a set of partial differential equations for Γ\Gamma in terms of GG. One can show that Γ\Gamma is a metric-compatible connection for GG with torsion, and that the curvature tensor of Γ\Gamma is that of an Einstein space. A curious 3-dimensional spatial geometry thus underlies the gauge-invariant configuration space of the theory, although the Hamiltonian is not invariant under spatial coordinate transformations. Spatial derivative terms in the energy density are singular when detG=detB=0\det G=\det B=0. These singularities are the analogue of the centrifugal barrier of quantum mechanics, and physical wave-functionals are forced to vanish in a certain manner near detB=0\det B=0. It is argued that such barriers are an inevitable result of the projection on the gauge-invariant subspace of the Hilbert space, and that the barriers are a conspicuous way in which non-abelian gauge theories differ from scalar field theories.Comment: 19 pages, TeX, CTP #223
    corecore