69,379 research outputs found

    Synthesising and utilising complex evidence to inform policy in education and health.

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    Oslo, Norway, May 19 to 21, 200

    The yield and post-yield behavior of high-density polyethylene

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    An experimental and analytical evaluation was made of the yield and post-yield behavior of high-density polyethylene, a semi-crystalline thermoplastic. Polyethylene was selected for study because it is very inexpensive and readily available in the form of thin-walled tubes. Thin-walled tubular specimens were subjected to axial loads and internal pressures, such that the specimens were subjected to a known biaxial loading. A constant octahederal shear stress rate was imposed during all tests. The measured yield and post-yield behavior was compared with predictions based on both isotropic and anisotropic models. Of particular interest was whether inelastic behavior was sensitive to the hydrostatic stress level. The major achievements and conclusions reached are discussed

    Data protection: the challenges facing social networking

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    The popularity of social networking sites has increased dramatically over the past decade. A recent report indicated that thirty-eight percent of online users have a social networking profile. Many of these social networking site users (SNS users) post or provide personal information over the internet every day. According to the latest OfCom study, the average adult SNS user has profiles on 1.6 sites and most check their profiles at least once every other day. However, the recent rise in social networking activity has opened the door to the misuse and abuse of personal information through identity theft, cyber stalking, and undesirable screenings by prospective employers. Behavioral advertising programs have also misused personal information available on social networking sites. Society is now facing an important question: what level of privacy should be expected and required within the social networking environment

    Does HBT Measure the Freeze-out Source Distribution?

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    It is generally assumed that as a result of multiple scattering, the source distribution measured in HBT interferometry corresponds to a chaotic source at freeze-out. This assumption is subject to question as effects of multiple scattering in HBT measurements must be investigated within a quantum-mechanical framework. Applying the Glauber multiple scattering theory at high energies and the optical model at lower energies, we find that multiple scattering leads to an effective HBT density distribution that depends on the initial chaotic source distribution with an absorption.Comment: 4 pages, talk presented at QM2004 Conference, January 11-17, 2004, Oakland, California, USA, to be published in the Proceeding

    RAMESES publication standards: realist syntheses

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    PMCID: PMC3558331This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

    Spin-transfer mechanism for magnon-drag thermopower

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    We point out a relation between the dissipative spin-transfer-torque parameter ÎČ\beta and the contribution of magnon drag to the thermoelectric power in conducting ferromagnets. Using this result we estimate ÎČ\beta in iron at low temperatures, where magnon drag is believed to be the dominant contribution to the thermopower. Our results may be used to determine ÎČ\beta from magnon-drag-thermopower experiments, or, conversely, to infer the strength of magnon drag via experiments on spin transfer

    Behavior of shell-model configuration moments

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    An important input into reaction theory is the density of states or the level density. Spectral distribution theory (also known as nuclear statistical spectroscopy) characterizes the secular behavior of the density of states through moments of the Hamiltonian. One particular approach is to partition the model space into subspaces and find the moments in those subspaces; a convenient choice of subspaces are spherical shell-model configurations. We revisit these configuration moments and find, for complete 0ℏω0\hbar\omega many-body spaces, the following behaviors: (a) the configuration width is nearly constant for all configurations; (b) the configuration asymmetry or third moment is strongly correlated with the configuration centroid; (c) the configuration fourth moment, or excess is linearly related to the square to the configuration asymmetry. Such universal behavior may allow for more efficient modeling of the density of states in a shell-model framework.Comment: 12 pages, 8 figure
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