420 research outputs found

    Swelling and shrinking kinetics of a lamellar gel phase

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    We investigate the swelling and shrinking of L_beta lamellar gel phases composed of surfactant and fatty alcohol after contact with aqueous poly(ethylene-glycol) solutions. The height change Δh(t)\Delta h(t) is diffusion-like with a swelling coefficient, S: Δh=St\Delta h = S \sqrt{t}. On increasing polymer concentration we observe sequentially slower swelling, absence of swelling, and finally shrinking of the lamellar phase. This behavior is summarized in a non-equilibrium diagram and the composition dependence of S quantitatively described by a generic model. We find a diffusion coefficient, the only free parameter, consistent with previous measurements.Comment: 3 pages, 4 figures to appear in Applied Physics Letter

    Monolith formation and ring-stain suppression in low-pressure evaporation of poly(ethylene oxide) droplets

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    When droplets of dilute suspensions are left to evaporate the final dry residue is typically the familiar coffee-ring stain, with nearly all material deposited at the initial triple line (Deegan et al, Nature, vol. 389, 1997, pp. 827-829). However, aqueous poly(ethylene oxide) (PEO) droplets only form coffee-ring stains for a very narrow range of the experimental parameters molecular weight, concentration and drying rate. Instead, over a wide range of values they form either a flat disk or a very distinctive tall central monolith via a four-stage deposition process which includes a remarkable bootstrap-building step. To predict which deposit will form, we present a quantitative model comparing the effects of advective build-up at the triple line to diffusive flux and use this to calculate a dimensionless number χ. By experimentally varying concentration and flux (using a low-pressure drying chamber), the prediction is tested over nearly two orders of magnitude in both variables and shown to be in good agreement with the boundary between disks and monoliths at χ ≈ 1.6

    De-ossifying the Internet Transport Layer : A Survey and Future Perspectives

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    ACKNOWLEDGMENT The authors would like to thank the anonymous reviewers for their useful suggestions and comments.Peer reviewedPublisher PD

    An evaluation of a personalised text message reminder compared to a standard text message on postal questionnaire response rates: an embedded randomised controlled trial

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    Abstract Background: Research outcome data is commonly collected using postal questionnaires; however, poor response can introduce bias and reduce statistical power. Text messaging is simple, cost-effective, and can be customised to the individual. Personalised, reminder text messages may improve response rates. Methods: A two-arm, parallel group ‘Study within a Trial’ (SWAT) was embedded within the Occupational Therapist Intervention Study (OTIS), a randomised controlled trial of a home assessment for falls prevention in older people. OTIS participants who provided a mobile phone number were randomly allocated (1:1) to receive either a personalised text message (Title, Surname, plus York Trials Unit (YTU) text) or the standard YTU text alone, prior to receiving their four-month post-randomisation follow-up postal questionnaire. The primary outcome measure was the proportion of participants who returned the questionnaire. Secondary outcomes were: time to response, completeness of response, requirement of a reminder letter, and cost-effectiveness. Binary data were compared using logistic regression and time to response by Cox Proportional Hazards regression. Results: A total of 403 participants were randomised: 201 to the personalised text and 202 to the standard text. Of the 283 participants included in the final analysis, 278 (98.2%) returned their questionnaire; 136 (97.8%) for the personalised text versus 142 (98.6%) for the standard text (adjusted odds ratio 0.64, 95% CI 0.10 to 3.88, p=0.63). The median time to response was nine days in both groups. In total, 271 (97.5%) participants returned a complete questionnaire; 133 (97.8%) in the personalised text versus 138 (97.2%) for the standard text. In total, 21 reminder letters were sent. The additional cost of personalised text messages was £0.04 per participant retained. Conclusions: Personalised texts were not superior to standard texts in any outcome assessed in our study. Further SWATs are needed to perform a meta-analysis and obtain more evidence. Registration: ISRCTN22202133; SWAT 35 Keywords: SWAT, Randomised Controlled Trial, personalised, SMS text, postal questionnaire, reminde

    Operating ranges, tunability and performance of CoDel and PIE

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    COMCOM-D-15-00474R1 This work was part-funded by the European Community under its Seventh Framework Programme through the Reducing Internet Transport Latency (RITE) project (ICT-317700). The views expressed are solely those of the authors.Peer reviewedPostprin

    Implementation of boolean neural networks on parallel computers

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    This paper analyses the parallel implementation using networks of transputers of a neural structure belonging to a particular class of neural architectures known as GSN neural networks. These architectures, belonging to the general clasa of RAM-based networks and composed 01 digitally specified processing nodes, have been implemented using different processing topologies, and performance in relatíon to both training and testing efficiency in a practical pattern recognition task has been evaluated.Eje: Redes Neuronales. Algoritmos genéticosRed de Universidades con Carreras en Informática (RedUNCI

    Reducing Internet Latency : A Survey of Techniques and their Merit

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    Bob Briscoe, Anna Brunstrom, Andreas Petlund, David Hayes, David Ros, Ing-Jyh Tsang, Stein Gjessing, Gorry Fairhurst, Carsten Griwodz, Michael WelzlPeer reviewedPreprin

    An embedded randomised controlled retention trial of personalised text messages compared to non-personalised text messages in an orthopaedic setting [version 1; peer review: 1 approved]

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    Background: Several studies have investigated whether personalising trial documentation can aid recruitment and retention. We did a ‘study within a trial’ (SWAT) evaluating the effectiveness of a personalised text message compared to a non-personalised text message, on the retention rate in a large orthopaedic trial. Methods: The SWAT was embedded in the Knee Replacement Bandaging Study (KReBS) trial. The primary outcome was the proportion of 12-month questionnaires returned. Secondary outcomes were the proportion of questionnaires completed and time to questionnaire return. Binary data were analysed using logistic regression and time to return using Cox proportional hazards regression. Odds ratios (OR) and hazard ratios (HR) are presented, with associated 95% confidence intervals (CI) and p-values. Results: In total, 1465 participants were included in the SWAT. In the personalised group, 644/723 (89.1%) of participants returned a questionnaire, compared to 654/742 (88.1%) in the non-personalised group. The absolute difference in return rate was 0.9% (95% CI: -2.3% to 4.2%; p=0.57). There was no evidence of a difference between the groups in the likelihood of returning a questionnaire (OR 1.09; 95% CI: 0.79 to 1.51; p=0.61), the likelihood of returning a complete questionnaire (OR 1.11; 95% CI: 0.82 to 1.51; p=0.50) nor in time to return (HR 1.05; 95% CI: 0.94 to 1.17; p=0.40). Conclusion: This SWAT adds to the growing evidence base for whether personalised text messages are effective. Registration: ISRCTN87127065 (20/02/2017); SWAT 35 (01/12/2015

    No excess harms from sustained-release morphine: A randomised placebo-controlled trial in chronic breathlessness

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    © Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ. Objectives: We aimed to identify and evaluate: (1) treatment-emergent adverse events (TEAE (worse or new since baseline)) and the subgroup of severe TEAEs in a placebo-controlled 7-day randomised trial of regular, low-dose, sustained-release oral morphine for chronic breathlessness and (2) clinical characteristics associated with TEAE. Methods: Safety analysis of trial data. Adults with chronic breathlessness (modified Medical Research Council breathlessness score ≥2) due to heart or lung disease, or cancer, not on regular opioids were eligible. Symptoms associated with opioids (TEAE of special interest) were systematically sought using Common Terminology Criteria for Adverse Events (CTCAE) grading. Other harms could be reported at any time. The relationship between characteristics and presence of ≥1 TEAE of special interest was explored using univariable logistic regression analyses. Results: 1449/5624 (26%) Adverse Events from 279 participants were TEAE of which 150/1449 (10%) were severe (CTCAE grades 3-5). 1086/5624 (75%) were events of special interest of which 41/1086 (4%) were severe. Compared with placebo, morphine was not associated with more TEAE or severe TEAE of special interest (TEAE: OR 0.53, 95% CI 0.21 to 1.38, p=0.20; severe TEAE: OR 0.96, 95% CI 0.27 to 3.41, p=0.95) nor with CTCAE severity grade (χ2=4.39, p=0.50). Among the 26/150 (17%) with severe TEAEs, study withdrawal was more common in the morphine arm (18/26 (69%) morphine arm; 8/26 (30%) placebo arm). None of the severe TEAEs was a respiratory harm. Conclusions: Severe morphine-associated toxicity was uncommon and not associated with study arm. Clinical consequences were minor and self-limiting. Trial registration number: ACTRN126000806268
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