4,589 research outputs found

    Scoping exercise on fallers’ clinics : report to the National Co-ordinating Centre for NHS Service Delivery and Organisation R & D (NCCSDO)

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    The National Service Framework for Older People has stated the need for fall-prevention programmes. An appraisal of fallers’ clinics launched by the National Institute for Health and Clinical Excellence (NICE) was suspended because of a lack of information regarding existing services and typology. This project aimed to determine the feasibility of conducting economic modelling to appraise fallers’ clinics. To achieve this a national survey of services and reviews of the evidence of effectiveness of various models of fallers’ clinics and screening tools were undertaken

    Preliminary investigations into a commercial thermal fingerprint developer for the visualisation of latent fingermarks on paper substrates

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    The Thermal Fingerprint Developer (TFD-2) developed by Foster and Freeman is the first commercially available instrument to solely utilise heat treatment to visualise latent fingermarks. The chemical-free TFD-2 was able to develop latent fingermarks on a variety of substrates. The manufacturer’s guidelines with regard to the optimal treatment settings were suitable for the more common substrates such as white copy paper; however, new protocols were required for the treatment of thermal paper. TFD-2’s ability to develop these samples and its use in sequence with traditional chemical reagents, such as 1,2-indanedione and physical developer, was demonstrated. The thermal developer may offer quick and easy heat application options for existing fingermark development reagents. It was found, however, that the TFD-2 developed samples lacked the detail and contrast afforded by conventional amino acid sensitive reagents under most conditions

    Chapter 11 An International Perspective on the Regulation of Rodenticides

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    In the late 1940s, anticoagulant active ingredients were introduced into the global rodenticide market. They were rapidly favored over existing rodenticides, such as red squill, zinc phosphide, strychnine and inorganic compounds, because they were comparatively inexpensive and did not appear to have any unpalatable taste, odor or cause any immediate post-ingestive reaction that could lead to bait shyness in rodents (Wardrop and Keeling 2008). The number of products registered in the United States (US) under Section 3 of the Federal Fungicide, Insecticide and Rodenticide Act (FIFRA), which was passed in 1947 and was the first US law to require product registration, illustrates the rapid dominance of anticoagulants in the US rodenticide market (Fig. 11.1). It is striking that the number of anticoagulant-based rodenticide products (ARs) registered under FIFRA was more than two times greater than the other categories of rodenticide active ingredients 40 years after the enactment of FIFRA. The greatest number of rodenticide products registered in a single year under Section 3 of FIFRA (750) was in 1985, and ARs accounted for 547 (73%) o

    Non-Universal Quasi-Long Range Order in the Glassy Phase of Impure Superconductors

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    The structural correlation functions of a weakly disordered Abrikosov lattice are calculated for the first time in a systematic RG-expansion in d=4-\epsilon dimensions. It is shown, that in the asymptotic limit the Abrikosov lattice exhibits still quasi long range translational order described by a non-universal exponent \bar\eta_{\bf G} which depends on the ratio of the renormalized elastic constants \kappa =\tilde c_{66}/\tilde c_{11} of the flux line (FL) lattice. Our calculations show clearly three distinct scaling regimes corresponding to the Larkin, the manifold and the asymptotic Bragg glass regime. On a wide range of intermediate length scales the FL displacement correlation function increases as a power law with twice of the manifold roughness exponent \zeta_{rm}(\kappa), which is also non-universal. Our results, in particular the \kappa-dependence of the exponents, are in variance with those of the variational treatment with replica symmetry breaking which allows in principle an experimental discrimination between the two approaches.Comment: 4 pages, 3 figure

    Nonuniversal Correlations and Crossover Effects in the Bragg-Glass Phase of Impure Superconductors

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    The structural correlation functions of a weakly disordered Abrikosov lattice are calculated in a functional RG-expansion in d=4−ϵd=4-\epsilon dimensions. It is shown, that in the asymptotic limit the Abrikosov lattice exhibits still quasi-long-range translational order described by a {\it nonuniversal} exponent ηG\eta_{\bf G} which depends on the ratio of the renormalized elastic constants κ=c66/c11\kappa ={c}_{66}/ {c}_{11} of the flux line (FL) lattice. Our calculations clearly demonstrate three distinct scaling regimes corresponding to the Larkin, the random manifold and the asymptotic Bragg-glass regime. On a wide range of {\it intermediate} length scales the FL displacement correlation function increases as a power law with twice the manifold roughness exponent ζRM(κ)\zeta_{\rm RM}(\kappa) , which is also {\it nonuniversal}. Correlation functions in the asymptotic regime are calculated in their full anisotropic dependencies and various order parameters are examined. Our results, in particular the κ\kappa-dependency of the exponents, are in variance with those of the variational treatment with replica symmetry breaking which allows in principle an experimental discrimination between the two approaches.Comment: 17 pages, 10 figure

    Strong-Coupling Phases of Frustrated Bosons on a 2-leg Ladder with Ring Exchange

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    Developing a theoretical framework to access quantum phases of itinerant bosons or fermions in two dimensions (2D) that exhibit singular structure along surfaces in momentum space but have no quasi-particle description remains as a central challenge in the field of strongly correlated physics. In this paper we propose that distinctive signatures of such 2D strongly correlated phases will be manifest in quasi-one-dimensional "N-leg ladder" systems. Characteristic of each parent 2D quantum liquid would be a precise pattern of 1D gapless modes on the N-leg ladder. These signatures could be potentially exploited to approach the 2D phases from controlled numerical and analytical studies in quasi-1D. As a first step we explore itinerant boson models with a frustrating ring exchange interaction on the 2-leg ladder, searching for signatures of the recently proposed two-dimensional d-wave correlated Bose liquid (DBL) phase. A combination of exact diagonalization, density matrix renormalization group, variational Monte Carlo, and bosonization analysis of a quasi-1D gauge theory, all provide compelling evidence for the existence of a new strong-coupling phase of bosons on the 2-leg ladder which can be understood as a descendant of the two-dimensional DBL. We suggest several generalizations to quantum spin and electron Hamiltonians on ladders which could likewise reveal fingerprints of such 2D non-Fermi liquid phases.Comment: 22 pages, 15 figure

    Problems With the Vortex-Boson Mapping in 1+1 Dimensions

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    Using the well known boson mapping, we relate the transverse magnetic susceptibility of a system of flux vortices in 1+1 dimensions to an appropriately defined conductivity of a one-dimensional boson system. The tilt response for a system free of disorder is calculated directly, and it is found that a subtle order of limits is required to avoid deceptive results.Comment: 4 Pages (REVTeX 3.0). Postscript file for this paper is available on the World Wide Web at http://cmtw.harvard.edu/~simon/

    Dynamics of the Wang-Landau algorithm and complexity of rare events for the three-dimensional bimodal Ising spin glass

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    We investigate the performance of flat-histogram methods based on a multicanonical ensemble and the Wang-Landau algorithm for the three-dimensional +/- J spin glass by measuring round-trip times in the energy range between the zero-temperature ground state and the state of highest energy. Strong sample-to-sample variations are found for fixed system size and the distribution of round-trip times follows a fat-tailed Frechet extremal value distribution. Rare events in the fat tails of these distributions corresponding to extremely slowly equilibrating spin glass realizations dominate the calculations of statistical averages. While the typical round-trip time scales exponential as expected for this NP-hard problem, we find that the average round-trip time is no longer well-defined for systems with N >= 8^3 spins. We relate the round-trip times for multicanonical sampling to intrinsic properties of the energy landscape and compare with the numerical effort needed by the genetic Cluster-Exact Approximation to calculate the exact ground state energies. For systems with N >= 8^3 spins the simulation of these rare events becomes increasingly hard. For N >= 14^3 there are samples where the Wang-Landau algorithm fails to find the true ground state within reasonable simulation times. We expect similar behavior for other algorithms based on multicanonical sampling.Comment: 9 pages, 12 figure

    Short-range spin glasses and Random Overlap Structures

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    Properties of Random Overlap Structures (ROSt)'s constructed from the Edwards-Anderson (EA) Spin Glass model on Zd\Z^d with periodic boundary conditions are studied. ROSt's are N×N\N\times\N random matrices whose entries are the overlaps of spin configurations sampled from the Gibbs measure. Since the ROSt construction is the same for mean-field models (like the Sherrington-Kirkpatrick model) as for short-range ones (like the EA model), the setup is a good common ground to study the effect of dimensionality on the properties of the Gibbs measure. In this spirit, it is shown, using translation invariance, that the ROSt of the EA model possesses a local stability that is stronger than stochastic stability, a property known to hold at almost all temperatures in many spin glass models with Gaussian couplings. This fact is used to prove stochastic stability for the EA spin glass at all temperatures and for a wide range of coupling distributions. On the way, a theorem of Newman and Stein about the pure state decomposition of the EA model is recovered and extended.Comment: 27 page

    The association of dyslexia and developmental speech and language disorder candidate genes with reading and language abilities in adults

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    Reading and language abilities are critical for educational achievement and success in adulthood. Variation in these traits is highly heritable, but the underlying genetic architecture is largely undiscovered. Genetic studies of reading and language skills traditionally focus on children with developmental disorders; however, much larger unselected adult samples are available, increasing power to identify associations with specific genetic variants of small effect size. We introduce an Australian adult population cohort (41.7–73.2 years of age, N = 1505) in which we obtained data using validated measures of several aspects of reading and language abilities. We performed genetic association analysis for a reading and spelling composite score, nonword reading (assessing phonological processing: a core component in learning to read), phonetic spelling, self-reported reading impairment and nonword repetition (a marker of language ability). Given the limited power in a sample of this size (~80% power to find a minimum effect size of 0.005), we focused on analyzing candidate genes that have been associated with dyslexia and developmental speech and language disorders in prior studies. In gene-based tests, FOXP2, a gene implicated in speech/language disorders, was associated with nonword repetition (p < .001), phonetic spelling (p = .002) and the reading and spelling composite score (p < .001). Gene-set analyses of candidate dyslexia and speech/language disorder genes were not significant. These findings contribute to the assessment of genetic associations in reading and language disorders, crucial for understanding their etiology and informing intervention strategies, and validate the approach of using unselected adult samples for gene discovery in language and reading
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