30,049 research outputs found

    Unethical aspects of homeopathic dentistry

    Get PDF
    In the last year there has been a great deal of public debate about homeopathy, the system of alternative medicine whose main principles are that like cures like and that potency increases relative to dilution. The House of Commons Select Committee on Science and Technology concluded in November 2009 that there is no evidence base for homeopathy, and agreed with some academic commentators that homeopathy should not be funded by the NHS. While homeopathic doctors and hospitals are quite commonplace, some might be surprised to learn that there are also many homeopathic dentists practising in the UK. This paper examines the statements made by several organisations on behalf of homeopathic dentistry and suggests that they are not entirely ethical and may be in breach of various professional guidelines

    Temperature elevation measured in a tissue-mimicking phantom for transvaginal ultrasound at clinical settings

    Get PDF
    INTRODUCTION: This paper reports the results of an audit to assess the possible thermal hazard associated with the clinical use of ultrasound scanners in UK Hospitals for transvaginal ultrasound imaging. METHODS: An anatomically relevant phantom composed of a block of agar-based tissue mimicking material with embedded thermal sensors was developed. Seventeen hospitals around the UK were visited and a total of 64 configurations were tested. A representative typical scanning protocol was adopted, which primarily used B-mode with 30 s periods of colour-flow and pulsed Doppler modes for both gynaecology and obstetrics pre-sets. RESULTS: The results confirmed that the highest temperature increase is always at the surface. The greatest temperature rise measured across all the systems was 3.6℃, with an average of 2.0℃ and 2.16℃ for gynaecology and obstetrics pre-sets, respectively. For some systems, the temperature increased rapidly when selecting one of the Doppler modes, so using them for longer than 30 s will in many cases lead to greater heating. It is also shown that, in agreement with previous studies, the displayed thermal index greatly underestimates the temperature rise, particularly close to the transducer face but even to distances approaching 2 cm. CONCLUSIONS: Overall, the results of the audit for the temperature rise during transvaginal ultrasound at clinical settings fell within the limits indicated by the national and international standards, for the pre-sets tested and following a representative typical scanning protocol. Only selected pre-sets were tested and the scanner outputs were not maximised (for example by using zoom, greater depth or narrow sector angles). Consequently, higher temperatures than those measured can certainly be achieved

    Parallel algorithm with spectral convergence for nonlinear integro-differential equations

    Get PDF
    We discuss a numerical algorithm for solving nonlinear integro-differential equations, and illustrate our findings for the particular case of Volterra type equations. The algorithm combines a perturbation approach meant to render a linearized version of the problem and a spectral method where unknown functions are expanded in terms of Chebyshev polynomials (El-gendi's method). This approach is shown to be suitable for the calculation of two-point Green functions required in next to leading order studies of time-dependent quantum field theory.Comment: 15 pages, 9 figure

    Enhancing active vision system categorization capability through uniform local binary patterns

    Get PDF
    Previous research in Neuro-Evolution controlled Active Vision Systems has shown its potential to solve various shape categorization and discrimination problems. However, minimal investigation has been done in using this kind of evolved system in solving more complex vision problems. This is partly due to variability in lighting conditions, reflection, shadowing etc., which may be inherent to these kinds of problems. It could also be due to the fact that building an evolved system for these kinds of problems may be too computationally expensive. We present an Active Vision System controlled Neural Network trained by a Genetic Algorithm that can autonomously scan through an image pre-processed by Uniform Local Binary Patterns [8]. We demonstrate the ability of this system to categorize more complex images taken from the camera of a Humanoid (iCub) robot. Preliminary investigation results show that the proposed Uniform Local Binary Pattern [8] method performed better than the gray-scale averaging method of [1] in the categorization tasks. This approach provides a framework that could be used for further research in using this kind of system for more complex image problems

    (Super)twistors and (super)strings

    Full text link
    The Lagrangian formulation of the D=4 bosonic string and superstring in terms of the (super)twistors is considered. The (super)twistor form of the equations of motion is derived and the kappa-symmetry transformation for the supertwistors is given. It is shown that the covariant kappa-symmetry gauge fixation results in the action quadratic in the (super)twistor variables.Comment: LaTeX, 17 page

    Simulation study of spatio-temporal correlations of earthquakes as a stick-slip frictional instability

    Full text link
    Spatio-temporal correlations of earthquakes are studied numerically on the basis of the one-dimensional spring-block (Burridge-Knopoff) model. As large events approach, the frequency of smaller events gradually increases, while, just before the mainshock, it is dramatically suppressed in a close vicinity of the epicenter of the upcoming mainshock, a phenomenon closely resembling the ``Mogi doughnut'
    • …
    corecore