101 research outputs found

    Estimates on counting functions associated to some hyperbolic operators and spectral properties

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    We study the distribution of the eigenvalues of a linear operator associated to a hyperbolic partial differential equation with periodic boundary conditions. Using some recent results concerning the distributions of the values of indefinite quadratic forms at integers, we are able to derive the equidistribution of the eigenvalues relatively to the Lebesgue measure with exact asymptotics. Also we provide an asymptotic lower bound in the rational case

    Using formal methods in distributed system design

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    Distributed systems are groups of networked computers, which have the same goal for their work. The terms "concurrent computing", "parallel computing", and "distributed computing" have a lot of overlap, and no clear distinction exists between them. The same system may be characterized both as "parallel" and "distributed"; the processors in a typical distributed system run concurrently in parallel. Parallel computing may be seen as a particular tightly coupled form of distributed computing, and distributed computing may be seen as a loosely coupled form of parallel computing. Nevertheless, it is possible to roughly classify concurrent systems as "parallel" or "distributed" using the following criteria. Philosophy is centrally concerned with arguments. The first question to be asked of any argument (or inference) is whether or not it is valid: That is, does its conclusion really follow from the cited premises? Validity of inference is the central problem of deductive logic. © The Authors, published by EDP Sciences, 2017

    3-[2-(1H-Benzimidazol-2-ylsulfan­yl)eth­yl]-1,3-oxazolidin-2-one

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    In the title compound, C12H13N3O2S, the oxazolidin ring displays an envelope conformation. The dihedral angle between the benzimidazole ring and the 1,3-oxazolidin-2-one mean plane is 69.85 (13)°. In the crystal, mol­ecules are linked by inter­molecular N—H⋯N hydrogen bonds, forming a chain parallel to the b axis

    Risk Factors, Clinical Outcomes and Prognostic Factors of Bacterial Keratitis: The Nottingham Infectious Keratitis Study

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    Background/aim: To examine the risk factors, clinical characteristics, outcomes and prognostic factors of bacterial keratitis (BK) in Nottingham, UK.Methods: This was a retrospective study of patients who presented to the Queen’s Medical Centre, Nottingham, with suspected BK during 2015-2019. Relevant data, including the demographic factors, risk factors, clinical outcomes, and potential prognostic factors, were analysed.Results: A total of 283 patients (n=283 eyes) were included; mean age was 54.421.0 years and 50.9% were male. Of 283 cases, 128 (45.2%) cases were culture-positive. Relevant risk factors were identified in 96.5% patients, with ocular surface diseases (47.3%), contact lens wear (35.3%) and systemic immunosuppression (18.4%) being the most common factors. Contact lens wear was most commonly associated with P. aeruginosa whereas Staphylococci spp. were most commonly implicated in non-contact lens-related BK cases (p=0.017). At presentation, culture-positive cases were associated with older age, worse presenting corrected-distance-visual-acuity (CDVA), larger epithelial defect and infiltrate, central location and hypopyon (all p≤0.01), when compared to culture-negative cases. Hospitalisation was required in 57.2% patients, with a mean length of stay of 8.0±8.3 days. Surgical intervention was required in 16.3% patients. Significant complications such as threatened/actual corneal perforation (8.8%), loss of perception of light vision (3.9%), and evisceration/enucleation (1.4%) were noted. Poor visual outcome (final corrected-distance-visual-acuity of ≤0.6 logMAR) and delayed corneal healing (>30 days from initial presentation) were significantly affected by age >50 years, infiltrate size >3mm, and reduced presenting vision (all p≤0.05). Conclusion: BK represents a significant ocular morbidity in the UK, with ocular surface diseases, contact lens wear and systemic immunosuppression being the main risk factors. Older age, large infiltrate, and poor presenting vision were predictive of poor visual outcome and delayed corneal healing, highlighting the importance of prevention and early intervention for BK

    Coastal sea level monitoring in the Mediterranean and Black seas

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    Employed for over a century, the traditional way of monitoring sea level variability by tide gauges – in combination with modern observational techniques like satellite altimetry – is an inevitable ingredient in sea level studies over the climate scales and in coastal seas. The development of the instrumentation, remote data acquisition, processing, and archiving in the last decades has allowed the extension of the applications to a variety of users and coastal hazard managers. The Mediterranean and Black seas are examples of such a transition – while having a long tradition of sea level observations with several records spanning over a century, the number of modern tide gauge stations is growing rapidly, with data available both in real time and as a research product at different time resolutions. As no comprehensive survey of the tide gauge networks has been carried out recently in these basins, the aim of this paper is to map the existing coastal sea level monitoring infrastructures and the respective data availability. The survey encompasses a description of major monitoring networks in the Mediterranean and Black seas and their characteristics, including the type of sea level sensors, measuring resolutions, data availability, and existence of ancillary measurements, altogether collecting information about 240 presently operational tide gauge stations. The availability of the Mediterranean and Black seas sea level data in the global and European sea level repositories has been also screened and classified following their sampling interval and level of quality check, pointing to the necessity of harmonization of the data available with different metadata and series in different repositories. Finally, an assessment of the networks' capabilities for their use in different sea level applications has been done, with recommendations that might mitigate the bottlenecks and ensure further development of the networks in a coordinated way, a critical need in the era of human-induced climate changes and sea level rise.En prens

    Correction. "The 5th edition of The World Health Organization Classification of Haematolymphoid Tumours: Lymphoid Neoplasms" Leukemia. 2022 Jul;36(7):1720-1748

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    We herein present an overview of the upcoming 5th edition of the World Health Organization Classification of Haematolymphoid Tumours focussing on lymphoid neoplasms. Myeloid and histiocytic neoplasms will be presented in a separate accompanying article. Besides listing the entities of the classification, we highlight and explain changes from the revised 4th edition. These include reorganization of entities by a hierarchical system as is adopted throughout the 5th edition of the WHO classification of tumours of all organ systems, modification of nomenclature for some entities, revision of diagnostic criteria or subtypes, deletion of certain entities, and introduction of new entities, as well as inclusion of tumour-like lesions, mesenchymal lesions specific to lymph node and spleen, and germline predisposition syndromes associated with the lymphoid neoplasms

    Coastal Sea Level Monitoring in the Mediterranean and Black Seas

    Get PDF
    Spanning over a century, a traditional way to monitor sea level variability by tide gauges is – in combination with modern observational techniques like satellite altimetry – an inevitable ingredient in sea level studies over the climate scales and in coastal seas. The development of the instrumentation, remote data acquisition, processing and archiving in last decades allowed for extending the applications towards a variety of users and coastal hazard managers. The Mediterranean and Black50 seas are an example for such a transition – while having a long tradition for sea level observations with several records spanning over a century, the number of modern tide gauge stations are growing rapidly, with data available both in real-time and as a research product at different time resolutions. As no comprehensive survey of the tide gauge networks has been carried out recently in these basins, the aim of this paper is to map the existing coastal sea level monitoring infrastructures and the respective data availability. The survey encompasses description of major monitoring networks in the Mediterranean and Black55 seas and their characteristics, including the type of sea level sensors, measuring resolutions, data availability and existence of ancillary measurements, altogether collecting information about 236 presently operational tide gauge stations. The availability of the Mediterranean and Black seas sea level data in the global and European sea level repositories has been also screened and classified following their sampling interval and level of quality-check, pointing to the necessity of harmonization of the data available with different metadata and series at different repositories. Finally, an assessment of the networks’ capabilities60 for their usage in different sea level applications has been done, with recommendations that might mitigate the bottlenecks and assure further development of the networks in a coordinated way, being that more necessary in the era of the human-induced climate changes and the sea level ris

    The 5th edition of the World Health Organization classification of haematolymphoid tumours: lymphoid neoplasms

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    We herein present an overview of the upcoming 5th edition of the World Health Organization Classification of Haematolymphoid Tumours focussing on lymphoid neoplasms. Myeloid and histiocytic neoplasms will be presented in a separate accompanying article. Besides listing the entities of the classification, we highlight and explain changes from the revised 4th edition. These include reorganization of entities by a hierarchical system as is adopted throughout the 5th edition of the WHO classification of tumours of all organ systems, modification of nomenclature for some entities, revision of diagnostic criteria or subtypes, deletion of certain entities, and introduction of new entities, as well as inclusion of tumour-like lesions, mesenchymal lesions specific to lymph node and spleen, and germline predisposition syndromes associated with the lymphoid neoplasms
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