20,494 research outputs found
Using geographical information systems for management of back-pain data
This is the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2002 MCB UP LtdIn the medical world, statistical visualisation has largely been confined to the realm of relatively simple geographical applications. This remains the case, even though hospitals have been collecting spatial data relating to patients. In particular, hospitals have a wealth of back pain information, which includes pain drawings, usually detailing the spatial distribution and type of pain suffered by back-pain patients. Proposes several technological solutions, which permit data within back-pain datasets to be digitally linked to the pain drawings in order to provide methods of computer-based data management and analysis. In particular, proposes the use of geographical information systems (GIS), up till now a tool used mainly in the geographic and cartographic domains, to provide novel and powerful ways of visualising and managing back-pain data. A comparative evaluation of the proposed solutions shows that, although adding complexity and cost, the GIS-based solution is the one most appropriate for visualisation and analysis of back-pain datasets
Interaction driven phases in the half-filled honeycomb lattice: an infinite density matrix renormalization group study
The emergence of the Haldane Chern insulator state due to strong short range
repulsive interactions in the half-filled fermionic spinless honeycomb lattice
model has been proposed and challenged with different methods and yet it still
remains controversial. In this work we revisit the problem using the infinite
density matrix renormalization group method and report numerical evidence
supporting i) the absence of the Chern insulator state, ii) two previously
unnoticed charge ordered phases and iii) the existence and stability of all the
non-topological competing orders that were found previously within mean field.
In addition, we discuss the nature of the corresponding phase transitions based
on our numerical data. Our work establishes the phase diagram of the
half-filled honeycomb lattice model tilting the balance towards the absence of
a Chern insulator phase for this model.Comment: 12 pages, 8 figures, published versio
Duality and exact correlations for a model of heat conduction
We study a model of heat conduction with stochastic diffusion of energy. We
obtain a dual particle process which describes the evolution of all the
correlation functions. An exact expression for the covariance of the energy
exhibits long-range correlations in the presence of a current. We discuss the
formal connection of this model with the simple symmetric exclusion process.Comment: 19 page
Near-Zero Modes in Superconducting Graphene
Vortices in the simplest superconducting state of graphene contain very low
energy excitations, whose existence is connected to an index theorem that
applies strictly to an approximate form of the relevant Bogoliubov-deGennes
equations. When Zeeman interactions are taken into account, the zero modes
required by the index theorem are (slightly) displaced. Thus the vortices
acquire internal structure, that plausibly supports interesting dynamical
phenomena.Comment: 9 pages, to appear in Proceedings of the Nobel Symposium on Graphene
and Quantum Matte
Alignment issues in photonic crystal device fabrication
An important requirement in the fabrication of photonic crystal structures is the correct relative alignment of structural elements. Accuracy should be in the order of some tens of nanometres. Some of the options for providing such accuracy are discussed. Examples are given of aligning defects with respect to a predefined 2D lattice, aligning access waveguides with respect to a small local photonic crystal structure, and the alignment of successive periodically structured layers in a 3D "woodpile" structure
How transnational stakeholders impact multinational corporations in the context of globalization
Stakeholder theory faces two closely related challenges in the light of globalization. On the one hand, globalization has not only led many firms to explore and expand into different parts of the world, it has also created possibilities for non-traditional stakeholders to âknock on the doorsâ of firms and make their concerns heard. On the other hand, the context of the multitude and complexity of novel stakeholder relationships that were not usually considered in stakeholder mappings renders the issue of corporate responsibility even more âpoliticalâ than stakeholder relationships have always been. However, exactly how such non-traditional stakeholders knock on the firmsâ doors has insufficiently been explored in stakeholder theorizing. Stakeholder theory appears to have difficulty in explaining the potential leverage that stakeholder groups without a clear and direct stake in a firm may exert over that particular firm. We propose to speak of âboomerang politicsâ as a general and overarching term in order to advance stakeholder theory in the light of the challenges from globalization by exploring how non-traditional stakeholders knock on firmsâ doors
Activism in the global sports apparel industry
F. den Hond, F.G.A. de Bakker, P. de Haan (2010), The sequential patterning of tactics: Activism in the global sports apparel industry, 1988â2002, International Journal of Sociology and Social Policy Vol.30, No.11, pp.648-66
Proximity effect in clean strong/weak/strong superconducting tri-layers
Recent measurements of the Josephson critical current through LSCO/LCO/LSCO
thin films showed an unusually large proximity effect. Using the Bogoliubov-de
Gennes (BdG) equations for a tight binding Hamiltonian we describe the
proximity effect in weak links between a superconductor with critical
temperature and one with critical temperature ', where '.
The weak link (N') is therefore a superconductor above its own critical
temperature and the superconducting regions are considered to have either
s-wave or d-wave symmetry. We note that the proximity effect is enhanced due to
the presence of superconducting correlations in the weak link. The dc Josephson
current is calculated, and we obtain a non-zero value for temperatures greater
than ' for sizes of the weak links that can be almost an order of
magnitude greater than the conventional coherence length. Considering pockets
of superconductivity in the N' layer, we show that this can lead to an even
larger effect on the Josephson critical current by effectively shortening the
weak link.Comment: submitted to Physical Review
Systematic Review of the Exposure Assessment and Epidemiology of High-Frequency Voltage Transients
Conclusions of epidemiological studies describing adverse health effects as a result of exposure to electromagnetic fields are not unanimous and often contradictory. It has been proposed that an explanation could be that high frequency voltage transients (dirty electricity [DE]) which are superimposed on 50/60Hz fields, but are generally not measured, is the real causal agent. DE has been linked to many different health and wellbeing effects, and on the basis of this an industry selling measurement and filtering equipment is growing. We reviewed the available peer-reviewed evidence for DE as a causal agent for adverse human health effects.A literature search was performed in the Cochrane Library, PubMed, Web of Science, Google Scholar and additional publications were obtained from reference lists and from the grey literature. This search resulted in 25 publications; 16 included primary epidemiological and/or exposure data. All studies were reviewed by both authors independently, and including a re-review of studies included in a review of data available up to July 31 2009 by one of the authors. DE has been measured differently in different studies and comparison data are not available. There is no evidence for 50 Graham/Stetzer (G/S) units as a safety threshold being anything more than arbitrary. The epidemiological evidence on human health effects of DE is primarily based on, often re-used, case descriptions. Quantitative evidence relies on self-reporting in non-blinded interventions, ecological associations, and one cross-sectional cohort study of cancer risk which does not point to DE as the causal agent. The available evidence for DE as an exposure affecting human health at present does not stand up to scientific scrutiny
A comparison of the entanglement measures negativity and concurrence
In this paper we investigate two different entanglement measures in the case
of mixed states of two qubits. We prove that the negativity of a state can
never exceed its concurrence and is always larger then
where is the concurrence of the state.
Furthermore we derive an explicit expression for the states for which the upper
or lower bound is satisfied. Finally we show that similar results hold if the
relative entropy of entanglement and the entanglement of formation are
compared
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