3,193 research outputs found
Thermo-mechanical analysis of dental silicone polymers
Soft lining materials are used to replace the inner surface of a conventional complete denture, especially for weak elderly patients, with delicate health who cannot tolerate the hard acrylic denture base. Most of these patients have fragile supporting mucosa, excessive residual ridge resorption, particularly on the mandibular arch. The application of a soft liner to the mandibular denture allows absorbing impact forces during mastication and relieving oral mucosa. Actually, the silicone rubbers constitute the main family of commercialised soft lining materials. This study was conducted to understand the relationships between the mechanical properties and the physical structure of polysiloxanes. For this purpose, a series of polysiloxanes of various chemical compositions have been investigated. The evolution of their physical structure as a function of temperature has been followed by differential scanning calorimetry (DSC). In order to facilitate comparisons, the mechanical modulus has been analysed upon the same heating rate using dynamic mechanical analysis (DMA). Polysiloxanes actually commercialised as soft denture liners are three-dimensional networks: the flexibility of chains allows a crystalline organisation in an amorphous phase leading to the low value of the shear modulus. The dynamic mechanical analysis shows that they are used in the rubbery state. So, polysiloxanes have steady mechanical properties during physiological utilisation
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Multi-target out-of-sequence data association
In data fusion systems, one often encounters measurements of past target locations and then wishes to deduce where the targets are currently located. Recent research on the processing of such out-of-sequence data has culminated in the development of a number of algorithms for solving the associated tracking problem. This paper reviews these different approaches in a common Bayesian framework and proposes an architecture that orthogonalises the data association and out-of-sequence problems such that any combination of solutions to these two problems can be used together. The emphasis is not on advocating one approach over another on the basis of computational expense, but rather on understanding the relationships between the algorithms so that any approximations made are explicit
Transcription enhancement of a digitised multi-lingual pamphlet collection: a case study and guide for similar projects
UCL Library Services holds an extensive collection of over 9,000 Jewish pamphlets, many of these extremely rare. Over the past five years, UCL has embarked on a project to widen access to this collection through an extensive programme of cataloguing, conservation and digitisation. With the cataloguing complete and the most fragile items conserved, the focus is now on making these texts available to global audiences via UCL Digital Collections website. The pamphlets were ranked for rarity, significance and fragility and the highest-scoring selected for digitisation. Unique identifiers allocated at the point of cataloguing were used to track individual pamphlets through the stages of the project. This guide details the text-enhancement methods used, highlighting particular issues relating to Hebrew scripts and early-printed texts. Initial attempts to enable images of these pamphlets to be searched digitally relied on the Optical Character Recognition (OCR) embedded within the software used to create the PDF files. Whilst satisfactory for texts chiefly in Roman script, it provided no reliable means to search the extensive corpus of texts in Hebrew. Generous advice offered by the National Library of Israel led to our adoption of ABBYY FineReader software as a means of enhancing the transcriptions embedded within the PDF files. Following image capture, JPEG files were used to create multi-page PDF files of each pamphlet. Pre-processing in ABBYY FineReader consisted of: setting the language and colour mode; detecting page orientation; selecting and refining areas of the text to be read; reading the text to produce a transcription. The resultant files were stored in folders according to language of text. The software highlighted spelling errors and doubtful readings. A verification tool allowed transcribers to correct these as required. However, some erroneous or doubtful readings were nevertheless genuine words and not highlighted; it was therefore essential to proofread the text, particularly for early-printed scripts. Transcribers maintained logs of common errors; additionally, problems with Hebrew vocalisations, cursive and Gothic scripts were noted. During initial quality checks of the transcriptions, many text searches were unsuccessful due to previously unidentified spacings occurring within words. This was generally linked to the font size being too small. Maintaining logs of font sizes used led to the adoption of a minimum of Arial 8 or Times New Roman 10 in transcribed text. The methodology was revised to include the preliminary quality-checking of one page. We concluded that it was difficult to develop a standardised procedure applicable to all texts given the variance in language, script and typography. However, we concluded that the font Arial gave the most successful accuracy ratings for Hebrew script, minimum text size 17, minimum title size 25. ABBYY file preparation took a minimum of 1.5 hours per pamphlet; transcription correction took an average of 10.4 minutes per page; the final quality check took 30 minutes per pamphlet. On average, the work on each pamphlet took a minimum of 6 hours to complete. As a result of the project, average accuracy ratings improved from 60% to 89%, the greatest improvement being for pre-1800 and Hebrew script publications. We are therefore inclined to focus future transcription-enhancement activity on these types of publication for the remainder of our Jewish Pamphlet Collections
Electromagnetic Form Factors of the Nucleon and Compton Scattering
We review the experimental and theoretical status of elastic electron
scattering and elastic low-energy photon scattering (with both real and virtual
photons) from the nucleon. As a consequence of new experimental facilities and
new theoretical insights, these subjects are advancing with unprecedented
precision. These reactions provide many important insights into the spatial
distributions and correlations of quarks in the nucleon.Comment: 47 pages, 18 figures, includes corrections and updates to published
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The economic burden of cancer in the UK: a study of survivors treated with curative intent.
OBJECTIVE: We aim to describe the economic burden of UK cancer survivorship for breast, colorectal and prostate cancer patients treated with curative intent, 1 year post-diagnosis. METHODS: Patient-level data were collected over a 3-month period 12-15 months post-diagnosis to estimate the monthly societal costs incurred by cancer survivors. Self-reported resource utilisation data were obtained via the electronic Patient-reported Outcomes from Cancer Survivors system and included community-based health and social care, medications, travel costs and informal care. Hospital costs were retrieved through data linkage. Multivariate regression analysis was used to examine cost predictors. RESULTS: Overall, 298 patients were included in the analysis, including 136 breast cancer, 83 colorectal cancer and 79 prostate cancer patients. The average monthly societal cost was US316-US279, 95%CI: US351) [mean: £177, 95%CI: £131-£224], patients' out-of-pocket (OOP) expenses (mean: US15-US110, 95%CI: US162) [mean: £70, 95%CI: £38-£102]. The distribution of costs was skewed with a small number of patients incurring very high costs. Multivariate analyses showed higher societal costs for breast cancer patients. Significant predictors of OOP costs included age and socioeconomic deprivation. CONCLUSIONS: This study found the economic burden of cancer survivorship is unevenly distributed in the population and that cancer survivors may still incur substantial costs over 1 year post-diagnosis. In addition, this study illustrates the feasibility of using an innovative online data collection platform to collect patient-reported resource utilisation information. Copyright © 2015 John Wiley & Sons, Ltd
Analysis of the Brinkman-Forchheimer equations with slip boundary conditions
In this work, we study the Brinkman-Forchheimer equations driven under slip
boundary conditions of friction type. We prove the existence and uniqueness of
weak solutions by means of regularization combined with the Faedo-Galerkin
approach. Next we discuss the continuity of the solution with respect to
Brinkman's and Forchheimer's coefficients. Finally, we show that the weak
solution of the corresponding stationary problem is stable
Preliminary evidence for reduced cortical activity in experienced guitarists during performance preparation for simple scale playing
Research using neuroscientific techniques has shown that less cortical activity occurs in the brains of experienced musicians and athletes than in the brains of novices when they plan and prepare to perform a motor skill. We used electroencephalography to observe cortical activity in the brains of experienced and novice guitarists preparing to play a scale on the guitar. The results, presented in this research note, confirm the findings of previous research and suggest that the motor preparation of experts is more efficient than that of novices. Cortical activity in music students could therefore, if tracked longitudinally, provide an objective marker of musical skill learning and be used to inform music learning, teaching and assessment practices
Viewing instructions accompanying action observation modulate corticospinal excitability
Action observation interventions may have the potential to contribute to improved motor function in motor (re)learning settings by promoting functional activity and plasticity in the motor regions of the brain. Optimal methods for delivering such interventions, however, have yet to be established. This experiment investigated the effect on corticospinal excitability of manipulating the viewing instructions provided to participants (N = 21) prior to action observation. Specifically, motor evoked potential responses measured from the right hand muscles following single-pulse transcranial magnetic stimulation to the left motor cortex were compared when participants were instructed to observe finger-thumb opposition movement sequences: (i) passively; (ii) with the intent to imitate the observed movement; or (iii) whilst simultaneously and actively imagining that they were performing the movement as they observed it. All three action observation viewing instructions facilitated corticospinal excitability to a greater extent than did observation of a static hand. In addition, the extent to which corticospinal excitability was facilitated was greater during combined observation and imagery, compared to passive observation. These findings have important implications for the design of action observation interventions in motor (re)learning settings, where instructions that encourage observers to simultaneously imagine themselves performing the observed movement may offer the current optimal method for improving motor function through action observation
Search for Nanosecond Near-infrared Transients around 1280 Celestial Objects
Stars and planetary system
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