555 research outputs found

    On Second-Order Monadic Monoidal and Groupoidal Quantifiers

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    We study logics defined in terms of second-order monadic monoidal and groupoidal quantifiers. These are generalized quantifiers defined by monoid and groupoid word-problems, equivalently, by regular and context-free languages. We give a computational classification of the expressive power of these logics over strings with varying built-in predicates. In particular, we show that ATIME(n) can be logically characterized in terms of second-order monadic monoidal quantifiers

    Randomisation and Derandomisation in Descriptive Complexity Theory

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    We study probabilistic complexity classes and questions of derandomisation from a logical point of view. For each logic L we introduce a new logic BPL, bounded error probabilistic L, which is defined from L in a similar way as the complexity class BPP, bounded error probabilistic polynomial time, is defined from PTIME. Our main focus lies on questions of derandomisation, and we prove that there is a query which is definable in BPFO, the probabilistic version of first-order logic, but not in Cinf, finite variable infinitary logic with counting. This implies that many of the standard logics of finite model theory, like transitive closure logic and fixed-point logic, both with and without counting, cannot be derandomised. Similarly, we present a query on ordered structures which is definable in BPFO but not in monadic second-order logic, and a query on additive structures which is definable in BPFO but not in FO. The latter of these queries shows that certain uniform variants of AC0 (bounded-depth polynomial sized circuits) cannot be derandomised. These results are in contrast to the general belief that most standard complexity classes can be derandomised. Finally, we note that BPIFP+C, the probabilistic version of fixed-point logic with counting, captures the complexity class BPP, even on unordered structures

    Study of Peri-Articular Anaesthetic for Replacement of the Knee (SPAARK): study protocol for a patient-blinded, randomised controlled superiority trial of liposomal bupivacaine

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    Background: Optimising the management of peri-operative pain and recovery following knee replacement has been identified as a patient priority. Current pain relief strategies use opiate-based analgesia; however, up to 50% of patients experience significant side effects. Local anaesthetic incisional infiltration is one alternative. The length of the duration of action is a major limiting factor of current local anaesthetic techniques. Liposomal bupivacaine has been reported to be effective for up to 72 h. This randomised controlled trial will evaluate the clinical and cost effectiveness of liposomal bupivacaine. Methods: SPAARK is a patient-blinded, multi-centre, active comparator, superiority, two-arm, parallel-group randomised controlled trial. Five hundred patients undergoing knee replacement will be recruited and randomised to liposomal bupivacaine plus bupivacaine hydrochloride or bupivacaine hydrochloride alone. The co-primary outcomes are the Quality of Recovery 40 measured at 72 h post-surgery and also cumulative pain measured daily using a 0–10 visual analogue scale for the first 3 days following surgery. Secondary outcomes include cumulative opioid consumption, fitness for discharge, functional outcomes assessed using the Oxford Knee Score and American Knee Society Score, the EuroQol five dimensions instrument and complications. A cost utility analysis is also planned. Discussion: The clinical effectiveness and cost effectiveness of liposomal bupivacaine have yet to be evaluated in the National Health Service, making this trial appropriate and timely. Trial registration: ISRCTN registry, ISRCTN54191675. Registered on 14 November 2017

    Winter activity of a population of greater horseshoe bats (Rhinolophus ferrumequinum)

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    Activity patterns of a greater horseshoe bats Rhinolophus ferrumequinum were investigated at caves in Cheddar (south-west England) during the hibernation season. An ultrasound detector and datalogger were used to monitor and record the number of echolocation calls in a single cave. Activity of R. ferrumequinum remained largely nocturnal throughout winter, and the mean time of activity over 24 hours was 88 to 369 minutes (1.47 to 6.15 hours) after sunset. There was an increase in diurnal activity from late May to early June, probably because bats remained active after foraging at dawn towards the end of the hibernation season. Visits to the cave did not increase bat activity. Cave air temperature reflected external climatic temperature, although there was variation in cave temperature and its range within and across caves. Individual R. ferrumequinum are usually dispersed in caves in regions where temperature fluctuations correlate with climatic variations in temperature. There was a positive correlation between the number of daily bat passes monitored by the bat detector and datalogger (= daily activity) and cave temperature. Nocturnal activity may sometimes be associated with winter feeding. Neither date nor barometric pressure had a significant effect on daily activity. Activity patterns largely reflected the findings from individual R. ferrumequinum studied by telemetry (Park, 1998), in that bat activity increased with cave and climatic temperatures, and the temporal pattern of activity remained consistently nocturnal throughout winter, starting at dusk

    Maintenance care for treated periodontitis patients

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    This paper is a review of current literature combined with clinical observations. Well-controlled maintenance care is a key consideration in the long-term prognosis of treated periodontitis patients. Periodic professional tooth cleaning every 3 to 4 months often is recommended. Furthermore, recent studies indicate a potential need for selected retreatment in problem areas, since minute residual accretions may be left behind during active therapy - even with “open” surgery. While efficient plaque control is essential for optimal results during the healing phase of periodontal therapy, periodic prophylaxis may prevent loss of clinical attachment over long periods of time even for patients with less than perfect oral hygiene.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72615/1/j.1600-051X.1987.tb02247.x.pd

    What's in a grade? The multidimensional nature of what teacher-assigned grades assess in high school

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    Historically, teacher-assigned grades have been seen as unreliable subjective measures of academic knowledge, since grades and standardized tests have traditionally correlated at about the 0.5 to 0.6 level, and thus explain about 25–35% of each other. However, emerging literature indicates that grades may be a multidimensional assessment of both student academic knowledge and a student's ability to negotiate the social processes of schooling, such as behavior, participation, and effort. This study analyzed the high school transcript component of the Education Longitudinal Study of 2002 (ELS:2002) using multidimensional scaling (MDS) to describe the relationships between core subject grades, non-core subject grades, and standardized test scores in mathematics and reading. The results indicate that when accounting for the academic knowledge component assessed through standardized tests, teacher-assigned grades may be a useful assessment of a student's ability at the non-cognitive aspects of school. Implications for practice, research, and policy are discussed

    An artificial intelligence method using FDG PET to predict treatment outcome in diffuse large B cell lymphoma patients

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    Convolutional neural networks (CNNs) may improve response prediction in diffuse large B-cell lymphoma (DLBCL). The aim of this study was to investigate the feasibility of a CNN using maximum intensity projection (MIP) images from 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) baseline scans to predict the probability of time-to-progression (TTP) within 2 years and compare it with the International Prognostic Index (IPI), i.e. a clinically used score. 296 DLBCL 18F-FDG PET/CT baseline scans collected from a prospective clinical trial (HOVON-84) were analysed. Cross-validation was performed using coronal and sagittal MIPs. An external dataset (340 DLBCL patients) was used to validate the model. Association between the probabilities, metabolic tumour volume and Dmaxbulk was assessed. Probabilities for PET scans with synthetically removed tumors were also assessed. The CNN provided a 2-year TTP prediction with an area under the curve (AUC) of 0.74, outperforming the IPI-based model (AUC = 0.68). Furthermore, high probabilities (> 0.6) of the original MIPs were considerably decreased after removing the tumours (< 0.4, generally). These findings suggest that MIP-based CNNs are able to predict treatment outcome in DLBCL
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