26,187 research outputs found

    Generic reality visualization modelling from process tomography sensor data in process design

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    The paper introduces a novel enabling step toward the widespread exploitation of the multi-dimensional process sensing offered by process tomography (PT) technology that has demonstrated a unique insight into many processes. Most current applications are laboratory or pilot-plant based. Generic system integration tools are proposed that deal systematically with PT data to accelerate the assessment and application of PT sensing, and hence deliver the large benefits expected to arise from large-scale exploitation of multi-dimensional sensing. Where multi-dimensional PT sensor data is available, a suite of enabling tools: reality visualisation modelling (RVM), are proposed as the complementary generic set of processing methods needed to take internal process state data, and yield directly usable process information, either for design model confirmation, or for effective plant control, or monitoring. A further step: Generic-RVM (GRVM) extends this concept through a generically defined process topology, complete with method and model set, to expedite mass-market application. The paper offers a practical illustration through a small pilot trial

    Remark on the open string pair production enhancement

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    Recent studies by one of the present authors along with his collaborators in [1-4] show that there exist the so-called open string pair production for a possible simplest system of two Dp branes, placed parallel at a separation and with each carrying different electric flux, in Type II superstring theories. Further this pair production can be greatly enhanced when a magnetic flux, sharing no common field strength index with the electric one, is added, implying then p3p \ge 3. Given this, one may wonder if further enhancement can be achieved by adding more magnetic flux(es) in a similar fashion. In this paper, we explore this possibility. It turns out that adding more such magnetic flux diminishes rather than enhances the pair production rate. This actually implies that the largest enhancement occurs at p=3p = 3 when the same realistic electric and magnetic fluxes are applied for all p3p \ge 3. Curiously one of D3 branes may be our own world and if so, the enhancement gives a possible opportunity to detect the pair production, therefore to test the underlying string theories.Comment: 14 pages, 0 figure

    Does taking vitamin, mineral and fatty acid supplements prevent cognitive decline? A systematic review of randomized controlled trials

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    Background Observational studies have shown associations between nutritional status and cognition in later life but evidence from intervention studies is unclear. The present study systematically reviewed the evidence on the effect of nutrient supplementation on cognitive function in people aged ≥65 years. Methods Databases including MEDLINE and EMBASE were searched up to 1 September 2006. Randomized controlled trials using at least one kind of vitamin, mineral or omega-3 fatty acid, evaluating standardized neuropsychological test(s), were included. There were no restrictions on participants' baseline nutritional status or cognitive function. Quality assessment and data abstraction were conducted by one author and checked by another. Results Of 4229 articles retrieved, 22 trials (3442 participants) were identified. Many were small, short duration and of poor methodology. Only 16 out of 122 cognitive tests were significantly different between groups. A meta-analysis showed no significant effect of taking B vitamins or antioxidant vitamins on global cognitive function. There was insufficient evidence to evaluate the effect of omega-3 fatty acids on any cognitive domains. Conclusion There was little evidence of a beneficial effect from taking B vitamins or antioxidant supplements on global cognitive function in later life. Larger-scale randomized controlled trials of longer duration in selected age groups are needed.Institute of Applied Health Science, University of Aberdeen; Chief Scientist Office of the Scottish Government Health Directorates; Chief Scientist of the Scottish Government Health Directorate

    On 1/4 BPS ((F, D1), (NS5, D5)) bound states of type IIB string theory

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    We construct two new SL(2,Z) invariant vacua of type IIB string theory which are bound states of (p,q)(p,q) strings with (m,n)(m,n) 5-branes, written as ((F, D1), (NS5, D5)) and preserve 1/4 of the full space-time supersymmetries. For the first case, the strings live inside the 5-brane world-volume and in the second case the strings are perpendicular to the 5-brane world-volume. In the first case, naively one would expect an attractive interaction between the strings and the 5-branes due to attractive force between F and D5 and also between D1 and NS5. We find that 1/4 BPS bound state exists only when the vacuum moduli satisfy certain condition which is found to be consistent with the no-force condition between the branes. No such complication arises for the second case. The tension formulae and the various other descendant states which can be obtained by the application of T-duality for both these bound states are discussed.Comment: 22 pages, 1 table, minor changes and one reference added, the version to appear in JHE

    Effect of Statistical Fluctuation in Monte Carlo Based Photon Beam Dose Calculation on Gamma Index Evaluation

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    The gamma-index test has been commonly adopted to quantify the degree of agreement between a reference dose distribution and an evaluation dose distribution. Monte Carlo (MC) simulation has been widely used for the radiotherapy dose calculation for both clinical and research purposes. The goal of this work is to investigate both theoretically and experimentally the impact of the MC statistical fluctuation on the gamma-index test when the fluctuation exists in the reference, the evaluation, or both dose distributions. To the first order approximation, we theoretically demonstrated in a simplified model that the statistical fluctuation tends to overestimate gamma-index values when existing in the reference dose distribution and underestimate gamma-index values when existing in the evaluation dose distribution given the original gamma-index is relatively large for the statistical fluctuation. Our numerical experiments using clinical photon radiation therapy cases have shown that 1) when performing a gamma-index test between an MC reference dose and a non-MC evaluation dose, the average gamma-index is overestimated and the passing rate decreases with the increase of the noise level in the reference dose; 2) when performing a gamma-index test between a non-MC reference dose and an MC evaluation dose, the average gamma-index is underestimated when they are within the clinically relevant range and the passing rate increases with the increase of the noise level in the evaluation dose; 3) when performing a gamma-index test between an MC reference dose and an MC evaluation dose, the passing rate is overestimated due to the noise in the evaluation dose and underestimated due to the noise in the reference dose. We conclude that the gamma-index test should be used with caution when comparing dose distributions computed with Monte Carlo simulation