1,250 research outputs found

    A Proof Strategy Language and Proof Script Generation for Isabelle/HOL

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    We introduce a language, PSL, designed to capture high level proof strategies in Isabelle/HOL. Given a strategy and a proof obligation, PSL's runtime system generates and combines various tactics to explore a large search space with low memory usage. Upon success, PSL generates an efficient proof script, which bypasses a large part of the proof search. We also present PSL's monadic interpreter to show that the underlying idea of PSL is transferable to other ITPs.Comment: This paper has been submitted to CADE2

    Aseptic meningitis in a patient taking etanercept for rheumatoid arthritis: a case report

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    Background \ud We report a case of a 53 year old lady recently commenced on etanercept, an anti-TNF (tumour necrosis factor) therapy for rheumatoid arthritis presenting with \ud confusion, pyrexia and an erythematous rash. \ud \ud Case presentation \ud A lumbar puncture was highly suggestive of bacterial meningitis, but CSF cultures produced no growth, and polymerase chain reactions (PCR) for all previously reported bacterial, fungal and viral causes of meningitis were negative. \ud \ud Conclusions \ud This case report describes aseptic meningitis as a previously unreported complication of etanercept therapy, and serves as a reminder of the rare but potentially lifethreatening risk of serious infections in patients taking anti-TNF therapy for a variety of conditions

    The planform mobility of river channel confluences: Insights from analysis of remotely sensed imagery

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    This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.River channel confluences are widely acknowledged as important geomorphological nodes that control the downstream routing of water and sediment, and which are locations for the preservation of thick fluvial deposits overlying a basal scour. Despite their importance, there has been little study of the stratigraphic characteristics of river junctions, or the role of confluence morphodynamics in influencing stratigraphic character and preservation potential. As a result, although it is known that confluences can migrate through time, models of confluence geomorphology and sedimentology are usually presented from the perspective that the confluence remains at a fixed location. This is problematic for a number of reasons, not least of which is the continuing debate over whether it is possible to discriminate between scour that has been generated by autocyclic processes (such as confluence scour) and that driven by allocyclic controls (such as sea-level change). This paper investigates the spatial mobility of river confluences by using the 40-year record of Landsat Imagery to elucidate the styles, rates of change and areal extent over which large river confluence scours may migrate. On the basis of these observations, a new classification of the types of confluence scour is proposed and applied to the Amazon and Ganges-Brahmaputra-Meghna (GBM) basins. This analysis demonstrates that the drivers of confluence mobility are broadly the same as those that drive channel change more generally. Thus in the GBM basin, a high sediment supply, large variability in monsoonal driven discharge and easily erodible bank materials result in a catchment where over 80% of large confluences are mobile over this 40-year window; conversely this figure is < 40% for the Amazon basin. These results highlight that: i) the potential areal extent of confluence scours is much greater than previously assumed, with the location of some confluences on the Jamuna (Brahmaputra) River migrating over a distance of 20 times the tributary channel width; ii) extensive migration in the confluence location is more common than currently assumed, and iii) confluence mobility is often tied to the lithological and hydrological characteristics of the drainage basins that determine sediment yield.This work was funded by NERC grant NE/I023228/1 to Sambrook Smith, Bull, Nicholas and Best

    The sedimentology of river confluences

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    This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.Channel confluences are key nodes within large river networks, and yet surprisingly little is known about their spatial and temporal evolution. Moreover, because confluences are associated with vertical scour that typically extends to several times the mean channel depth, the deposits associated with such scours should have a high preservation potential within the rock record. Paradoxically, such scours are rarely observed, and their preservation and sedimentological interpretation are poorly understood. The present study details results from a physically‐based morphodynamic model that is applied to simulate the evolution and alluvial architecture of large river junctions. Boundary conditions within the model were defined to approximate the junction of the Ganges and Jamuna rivers, Bangladesh, with the model output being supplemented by geophysical datasets collected at this junction. The numerical simulations reveal several distinct styles of sedimentary fill that are related to the morphodynamic behaviour of bars, confluence scour downstream of braid bars, bend scour and major junction scour. Comparison with existing, largely qualitative, conceptual models reveals that none of these can be applied simply, although elements of each are evident in the deposits generated by the numerical simulation and observed in the geophysical data. The characteristics of the simulated scour deposits are found to vary according to the degree of reworking caused by channel migration, a factor not considered adequately in current conceptual models of confluence sedimentology. The alluvial architecture of major junction scours is thus characterized by the prevalence of erosion surfaces in conjunction with the thickest depositional sets. Confluence scour downstream of braid bar and bend scour sites may preserve some large individual sets, but these locations are typically characterized by lower average set thickness compared to major junction scour and by a lack of large‐scale erosional surfaces. Areas of deposition not related to any of the specific scour types highlighted above record the thinnest depositional sets. This variety in the alluvial architecture of scours may go some way towards explaining the paradox of ancient junction scours, that while abundant large scours are likely in the rock record, they have been reported rarely. The present results outline the likely range of confluence sedimentology and will serve as a new tool for recognizing and interpreting these deposits in the ancient fluvial record.This work was funded by a UK Natural Environment Research Council award to Sambrook Smith (NE/I023228/1), Bull (NE/I023864/1) and Nicholas (NE/I023120/1)

    Graphical Reasoning in Compact Closed Categories for Quantum Computation

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    Compact closed categories provide a foundational formalism for a variety of important domains, including quantum computation. These categories have a natural visualisation as a form of graphs. We present a formalism for equational reasoning about such graphs and develop this into a generic proof system with a fixed logical kernel for equational reasoning about compact closed categories. Automating this reasoning process is motivated by the slow and error prone nature of manual graph manipulation. A salient feature of our system is that it provides a formal and declarative account of derived results that can include `ellipses'-style notation. We illustrate the framework by instantiating it for a graphical language of quantum computation and show how this can be used to perform symbolic computation.Comment: 21 pages, 9 figures. This is the journal version of the paper published at AIS

    Surgical Treatment of Iatrogenic Ventral Glottic Stenosis Using a Mucosal Flap Technique

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    OBJECTIVE: To describe a novel surgical technique for correcting postoperative ventral glottic stenosis (cicatrix or web formation) and the outcome in 2 Thoroughbred racehorses. STUDY DESIGN: Retrospective case report. ANIMALS: Thoroughbreds diagnosed with ventral glottic stenosis (n=2). METHODS: Horses presenting with iatrogenic ventral glottic stenosis and resultant exercise intolerance and abnormal exercise‐related noise were anesthetized and a midline sagittal skin incision was made over the ventral larynx and between the sternohyoideus muscles overlying the cricothyroid notch. The cricothyroid ligament, attached laryngeal cicatrix, and overlying mucosa were sagittally sectioned at the dorsal aspect of the cicatrix on the left side. The laryngeal mucosa, cicatrix, and underlying cricothyroid ligament immediately rostral and caudal to the cicatrix were sectioned in a medial (axial) direction as far as the right side of the cricothyroid notch. After resection of the majority of the attached cicatrix tissue, the residual mucosal flap (attached to the right side of the larynx) was reflected ventrally and sutured to the attachment of the cricothyroid ligament on the right side of the cricothyroid notch, creating an intact mucosal layer on the right side of the ventral larynx. RESULTS: Both horses had good intralaryngeal wound healing with minimal redevelopment of ventral glottic stenosis at 5 and 9 months postoperatively and were successfully returned to racing with complete absence of abnormal respiratory noise. CONCLUSION: The unique laryngeal anatomy of horses, with a cartilage‐free ventral laryngeal area (cricothyroid notch), allowed the use of this novel surgical technique to successfully treat ventral glottic stenosis

    'Choosing shoes': a preliminary study into the challenges facing clinicians in assessing footwear for rheumatoid patients

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    Background: Footwear has been accepted as a therapeutic intervention for the foot affected by rheumatoid arthritis (RA). Evidence relating to the objective assessment of footwear in patients with RA is limited. The aims of this study were to identify current footwear styles, footwear characteristics, and factors that influence footwear choice experienced by patients with RA. Methods: Eighty patients with RA were recruited from rheumatology clinics during the summer months. Clinical characteristics, global function, and foot impairment and disability measures were recorded. Current footwear, footwear characteristics and the factors associated with choice of footwear were identified. Suitability of footwear was recorded using pre-determined criteria for assessing footwear type, based on a previous study of foot pain. Results: The patients had longstanding RA with moderate-to severe disability and impairment. The foot and ankle assessment demonstrated a low-arch profile with both forefoot and rearfoot structural deformities. Over 50% of shoes worn by patients were opentype footwear. More than 70% of patients’ footwear was defined as being poor. Poor footwear characteristics such as heel rigidity and sole hardness were observed. Patients reported comfort (17%) and fit (14%) as important factors in choosing their own footwear. Only five percent (5%) of patients wore therapeutic footwear. Conclusions: The majority of patients with RA wear footwear that has been previously described as poor. Future work needs to aim to define and justify the specific features of footwear that may be of benefit to foot health for people with RA
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