5,235 research outputs found

    Clinical surveillance of thrombotic microangiopathies in Scotland, 2003-2005

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    The prevalence, incidence and outcomes of haemolytic uraemic syndrome (HUS) and thrombotic thrombocytopaenic purpura (TTP) are not well established in adults or children from prospective studies. We sought to identify both outcomes and current management strategies using prospective, national surveillance of HUS and TTP, from 2003 to 2005 inclusive. We also investigated the links between these disorders and factors implicated in the aetiology of HUS and TTP including infections, chemotherapy, and immunosuppression. Most cases of HUS were caused by verocytotoxin-producing Escherichia coli (VTEC), of which serotype O157 predominated, although other serotypes were identified. The list of predisposing factors for TTP was more varied although use of immunosuppressive agents and severe sepsis, were the most frequent precipitants. The study demonstrates that while differentiating between HUS and TTP is sometimes difficult, in most cases the two syndromes have quite different predisposing factors and clinical parameters, enabling clinical and epidemiological profiling for these disorders

    Introduction and sustained high coverage of the HPV bivalent vaccine leads to a reduction in prevalence of HPV 16/18 and closely related HPV types

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    In 2008, a national human papillomavirus (HPV) immunisation programme began in Scotland for 12–13 year old females with a three-year catch-up campaign for those under the age of 18. Since 2008, three-dose uptake of bivalent vaccine in the routine cohort aged 12–13 has exceeded 90% annually, while in the catch-up cohort overall uptake is 66%. To monitor the impact of HPV immunisation, a programme of national surveillance was established (pre and post introduction) which included yearly sampling and HPV genotyping of women attending for cervical screening at age 20. By linking individual vaccination, screening and HPV testing records, we aim to determine the impact of the immunisation programme on circulating type-specific HPV infection particularly for four outcomes: (i) the vaccine types HPV 16 or 18 (ii) types considered to be associated with cross-protection: HPV 31, 33 or 45; (iii) all other high-risk types and (iv) any HPV. From a total of 4679 samples tested, we demonstrate that three doses (n=1100) of bivalent vaccine are associated with a significant reduction in prevalence of HPV 16 and 18 from 29.8% (95% confidence interval 28.3, 31.3%) to 13.6% (95% confidence interval 11.7, 15.8%). The data also suggest cross-protection against HPV 31, 33 and 45. HPV 51 and 56 emerged as the most prevalent (10.5% and 9.6%, respectively) non-vaccine high-risk types in those vaccinated, but at lower rates than HPV 16 (25.9%) in those unvaccinated. This data demonstrate the positive impact of bivalent vaccination on the prevalence of HPV 16, 18, 31, 33 and 45 in the target population and is encouraging for countries which have achieved high-vaccine uptake

    ICP polishing of silicon for high quality optical resonators on a chip

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    Miniature concave hollows, made by wet etching silicon through a circular mask, can be used as mirror substrates for building optical micro-cavities on a chip. In this paper we investigate how ICP polishing improves both shape and roughness of the mirror substrates. We characterise the evolution of the surfaces during the ICP polishing using white-light optical profilometry and atomic force microscopy. A surface roughness of 1 nm is reached, which reduces to 0.5 nm after coating with a high reflectivity dielectric. With such smooth mirrors, the optical cavity finesse is now limited by the shape of the underlying mirror

    Worm algorithms for classical statistical models

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    We show that high-temperature expansions may serve as a basis for the novel approach to efficient Monte Carlo simulations. "Worm" algorithms utilize the idea of updating closed path configurations (produced by high-temperature expansions) through the motion of end points of a disconnected path. An amazing result is that local, Metropolis-type schemes may have dynamical critical exponents close to zero (i.e., their efficiency is comparable to the best cluster methods). We demonstrate this by calculating finite size scaling of the autocorrelation time for various (six) universality classes.Comment: 4 pages, latex, 2 figure

    Cyg X-3: Not seen in high-energy gamma rays by COS-B

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    COS-B had Cyg X-3 within its field of view during 7 observation periods between 1975 and 1982 for in total approximately 300 days. In the skymaps (70 meV E 5000 meV) of the Cyg-X region produced for each of these observations and in the summed map, a broad complex structure is visible in the region 72 deg approximately less than 1 approximately less than 85 deg, approximately less than 5 deg. No resolved source structure is visible at the position of Cyg X-3, but a weak signal from Cyg X-3 could be hidden in the structured gamma-ray background. Therefore, the data has been searched for a 4.8 h timing signature, as well as for a source signal in the sky map in addition to the diffuse background structure as estimated from tracers of atomic and molecular gas

    Quantifying recreational fishing catch and effort: a pilot study of shore-based fishers in the Perth Metropolitan area

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    Recreational fishing is a popular activity throughout Western Australia, including adjacent to the populous Perth Metropolitan area. Understanding the level of catch and effort associated with this activity is essential for the sustainable management of fish stocks. Whilst the focus of recent surveys in the Perth Metropolitan area has been on boat-based fishers targeting demersal species, shore-based fishing has not been measured for many years. Recent changes to management controls for these demersal species, including the implementation of a fishing boat licence, may increase existing pressures on nearshore stocks by displacing fishing effort onto these resources. Therefore, a need exists for the collection of information on the behaviour and catch of recreational shore-based fishers to support management measures

    Quantum cosmology with a curvature squared action

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    The correct quantum description for a curvature squared term in the action can be obtained by casting the action in the canonical form with the introduction of a variable which is the negative of the first derivative of the field variable appearing in the action, only after removing the total derivative terms from the action. We present the Wheeler-DeWitt equation and obtain the expression for the probability density and current density from the equation of continuity. Furthermore, in the weak energy limit we obtain the classical Einstein equation. Finally we present a solution of the wave equation.Comment: 8 pages, revte

    The effect of disorder on the critical temperature of a dilute hard sphere gas

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    We have performed Path Integral Monte Carlo (PIMC) calculations to determine the effect of quenched disorder on the superfluid density of a dilute 3D hard sphere gas. The disorder was introduced by locating set of hard cylinders randomly inside the simulation cell. Our results indicate that the disorder leaves the superfluid critical temperature basically unchanged. Comparison to experiments of helium in Vycor is made.Comment: 4 pages, 4 figure

    Neutron density distributions for atomic parity nonconservation experiments

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    The neutron distributions of Cs, Ba, Yb and Pb isotopes are described in the framework of relativistic mean-field theory. The self-consistent ground state proton and neutron density distributions are calculated with the relativistic Hartree-Bogoliubov model. The binding energies, the proton and neutron radii, and the quadrupole deformations are compared with available experimental data, as well as with recent theoretical studies of the nuclear structure corrections to the weak charge in atomic parity nonconservation experiments.Comment: 16 pages, RevTex, 11 eps figs, submitted to Phys. Rev.

    Enhanced spatial resolution through DFT rederivations of X-ray phase retrieval algorithms

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    Propagation-based phase-contrast imaging, used in conjunction with the phase retrieval algorithm based on the Transport-of-Intensity Equation (TIE) (Paganin et al., 2002), is commonly used to improve the sensitivity of X-ray imaging. Recently, a `Generalised Paganin Method' algorithm was published to correct the tendency of the TIE algorithm to over-blur images. The article, Paganin et al. 2020, provided a derivation of the new method and demonstrated a difference in the level of blurring applied by each algorithm. In this manuscript, we quantify the spatial resolution improvement and describe the optimal experimental conditions to observe this improvement. We link the effectiveness of the spatial resolution improvement to the imaging point spread function (PSF), incorporating the PSF to compare the blurring applied by each algorithm. We then validate this model through measurements of spatial resolution in experimental data imaging plastic phantoms and biological tissue, using detectors with different PSFs. By analysing edge-spread functions in CT data captured with indirect detectors with PSFs of several pixels in extent, we show negligible spatial resolution improvement when using the generalised Paganin method. However, a clear improvement in spatial resolution, up to 17%, was observed with direct detectors having PSFs of approximately one pixel in extent. Additionally, we demonstrate clear visual improvement in resolution in CT slices of rat lungs. Finally, we demonstrate the versatility of this improvement by generalising other phase retrieval algorithms, namely for multi-material samples and for spectral decomposition using propagation-based phase contrast, and experimentally verify improvements in spatial resolution
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