273 research outputs found

    Physiological basis for storage life extension in fresh sweet potato: Final technical report

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    The overall objective of this project was to work towards the identification of the major physiological and environmental factors affecting perishability of the fresh sweet potato root, and thereby to facilitate the identification of strategies for increasing shelf-life through cultivar selection and improved handling practice

    Charge Frustration Effects in Capacitively Coupled Two-Dimensional Josephson-Junction Arrays

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    We investigate the quantum phase transitions in two capacitively coupled two-dimensional Josephson-junction arrays with charge frustration. The system is mapped onto the S=1 and S=1/2S=1/2 anisotropic Heisenberg antiferromagnets near the particle-hole symmetry line and near the maximal-frustration line, respectively, which are in turn argued to be effectively described by a single quantum phase model. Based on the resulting model, it is suggested that near the maximal frustration line the system may undergo a quantum phase transition from the charge-density wave to the super-solid phase, which displays both diagonal and off- diagonal long-range order.Comment: 6 pages, 6 figures, to appear in Phys. Rev.

    Fidelity and leakage of Josephson qubits

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    The unit of quantum information is the qubit, a vector in a two-dimensional Hilbert space. On the other hand, quantum hardware often operates in two-dimensional subspaces of vector spaces of higher dimensionality. The presence of higher quantum states may affect the accuracy of quantum information processing. In this Letter we show how to cope with {\em quantum leakage} in devices based on small Josephson junctions. While the presence of higher charge states of the junction reduces the fidelity during gate operations we demonstrate that errors can be minimized by appropriately designing and operating the gates.Comment: 9 pages, Revtex, 2 eps figure

    Cotunneling Transport and Quantum Phase Transitions in Coupled Josephson-Junction Chains with Charge Frustration

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    We investigate the quantum phase transitions in two capacitively coupled chains of ultra-small Josephson-junctions, with emphasis on the external charge effects. The particle-hole symmetry of the system is broken by the gate voltage applied to each superconducting island, and the resulting induced charge introduces frustration to the system. Near the maximal-frustration line, where the system is transformed into a spin-1/2 Heisenberg antiferromagnetic chain, cotunneling of the particles along the two chains is shown to play a major role in the transport and to drive a quantum phase transition out of the charge-density wave insulator, as the Josephson-coupling energy is increased. We also argue briefly that slightly off the symmetry line, the universality class of the transition remains the same as that right on the line, still being driven by the particle-hole pairs.Comment: Final version accepted to Phys. Rev. Lett. (Longer version is available from http://ctp.snu.ac.kr/~choims/

    Geometric Quantum Computation on Solid-State Qubits

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    An adiabatic cyclic evolution of control parameters of a quantum system ends up with a holonomic operation on the system, determined entirely by the geometry in the parameter space. The operation is given either by a simple phase factor (a Berry phase) or a non-Abelian unitary operator depending on the degeneracy of the eigenspace of the Hamiltonian. Geometric quantum computation is a scheme to use such holonomic operations rather than the conventional dynamic operations to manipulate quantum states for quantum information processing. Here we propose a geometric quantum computation scheme which can be realized with current technology on nanoscale Josephson-junction networks, known as a promising candidate for solid-state quantum computer.Comment: 6 figures; to appear in J. Phys.: Condens. Mat

    A Study into the assessment and reporting of employability skills of senior secondary students

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    In order to investigate the most effective ways of assessing and reporting on the employability skills of senior secondary students, the Commonwealth Department of Education, Science and Training (DEST) commissioned this report. The main activity was to evaluate options for assessing and reporting on eight employability skills against five criteria—validity, reliability, objectivity, feasibility, and usability—and to recommend a preferred approach. This work was undertaken by the Australian Council for Educational Research (ACER) in the period July 2007 to January 2008, during which time the (new) Department of Education, Employment and Workplace Relations (DEEWR) became responsible for the initiative. The starting point for this work was to come to terms with the eight employability skills and their respective facets from the Employability Skills Framework (ACCI & BCA, 2002). The employability skills are: Communication; Initiative & Enterprise; Learning; Planning & Organising; Problem Solving; Self-management; Teamwork; and Technology. Facets are elements of the skill that employers have identified as important, with the specific mix and priority of facets being job-dependent. One of the facets of Communication, for example, is ‘Reading independently’. As an adjunct activity to this study, the University of Western Sydney conducted a survey of the current level of employer satisfaction with the eight identified employability skills and how employers assess them (Costley, Power, Watson, Steele, & Sproats, 2007). Consultations were undertaken with employers, and representatives of parent organisations, school systems including teachers and leaders, and Australia’s three peak business organisations, ACCI, BCA, and the Australian Industry Group (AIG). An advisory group set up by DEST had the same representation. In addition, expert input was sought on detailed matters of assessment and reporting

    Current drag in capacitevly coupled Luttinger constrictions

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    We study the current drag in the system of two electrostatically coupled finite 1D electron channels. We present the perturbation theory results along with the results for two non-perturbative regimes. It is shown that the drag may become absolute, that is, the currents in the channels are equal in a finite window of the bias voltages.Comment: 4 pages RevTeX, 3 postscript figure

    A generation apart? Youth and political participation in Britain

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    Conventional wisdom holds that young people in Britain are alienated from politics, with some claiming that this reflects a wider crisis of legitimacy that should be met by initiatives to increase citizenship. This article addresses these areas, presenting both panel survey and focus group data from first-time voters. It concludes that, contrary to the findings from many predominantly quantitative studies of political participation, young people are interested in political matters, and do support the democratic process. However they feel a sense of anti-climax having voted for the first time, and are critical of those who have been elected to positions of political power. If they are a generation apart, this is less to do with apathy, and more to do with their engaged scepticism about ‘formal’ politics in Britain

    Non-equlibrium effects in transport through quantum dots

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    The role of non-equilibrium effects in the conductance through quantum dots is investigated. Associated with single-electron tunneling are shake-up processes and the formation of excitonic-like resonances. They change qualitatively the low temperature properties of the system. We analyze by quantum Monte Carlo methods the renormalization of the effective capacitance and the gate-voltage dependent conductance. Experimental relevance is discussed.Comment: 10 pages, 8 postscript figure

    INSPIRE (INvestigating Social and PractIcal suppoRts at the End of life): Pilot randomised trial of a community social and practical support intervention for adults with life-limiting illness

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    YesBACKGROUND: For most people, home is the preferred place of care and death. Despite the development of specialist palliative care and primary care models of community based service delivery, people who are dying, and their families/carers, can experience isolation, feel excluded from social circles and distanced from their communities. Loneliness and social isolation can have a detrimental impact on both health and quality of life. Internationally, models of social and practical support at the end of life are gaining momentum as a result of the Compassionate Communities movement. These models have not yet been subjected to rigorous evaluation. The aims of the study described in this protocol are: (1) to evaluate the feasibility, acceptability and potential effectiveness of The Good Neighbour Partnership (GNP), a new volunteer-led model of social and practical care/support for community dwelling adults in Ireland who are living with advanced life-limiting illness; and (2) to pilot the method for a Phase III Randomised Controlled Trial (RCT). DESIGN: The INSPIRE study will be conducted within the Medical Research Council (MRC) Framework for the Evaluation of Complex Interventions (Phases 0-2) and includes an exploratory two-arm delayed intervention randomised controlled trial. Eighty patients and/or their carers will be randomly allocated to one of two groups: (I) Intervention: GNP in addition to standard care or (II) Control: Standard Care. Recipients of the GNP will be asked for their views on participating in both the study and the intervention. Quantitative and qualitative data will be gathered from both groups over eight weeks through face-to-face interviews which will be conducted before, during and after the intervention. The primary outcome is the effect of the intervention on social and practical need. Secondary outcomes are quality of life, loneliness, social support, social capital, unscheduled health service utilisation, caregiver burden, adverse impacts, and satisfaction with intervention. Volunteers engaged in the GNP will also be assessed in terms of their death anxiety, death self efficacy, self-reported knowledge and confidence with eleven skills considered necessary to be effective GNP volunteers. DISCUSSION: The INSPIRE study addresses an important knowledge gap, providing evidence on the efficacy, utility and acceptability of a unique model of social and practical support for people living at home, with advanced life-limiting illness. The findings will be important in informing the development (and evaluation) of similar service models and policy elsewhere both nationally and internationally. TRIAL REGISTRATION: ISRCTN18400594 18(th) February 2015
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