374 research outputs found

    Contention resolution in optical packet-switched cross-connects

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    Contention resolution in optical packet-switched cross-connects

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    Parallel Recursive State Compression for Free

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    This paper focuses on reducing memory usage in enumerative model checking, while maintaining the multi-core scalability obtained in earlier work. We present a tree-based multi-core compression method, which works by leveraging sharing among sub-vectors of state vectors. An algorithmic analysis of both worst-case and optimal compression ratios shows the potential to compress even large states to a small constant on average (8 bytes). Our experiments demonstrate that this holds up in practice: the median compression ratio of 279 measured experiments is within 17% of the optimum for tree compression, and five times better than the median compression ratio of SPIN's COLLAPSE compression. Our algorithms are implemented in the LTSmin tool, and our experiments show that for model checking, multi-core tree compression pays its own way: it comes virtually without overhead compared to the fastest hash table-based methods.Comment: 19 page

    Placental localization and assessment of foetal whole bodyand gonadal radiation following R131ISA placentography

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    Accurate localization of the placenta is rapidly becoming of the utmost importance in the modern practice of obstetrics. In the diagnosis and treatment of placenta praevia and the performance of amniocentesis, knowledge as to the site of placental insertion is imperative. Furthermore, the situation of the placenta plays a definite role in labour and delivery

    An optical threshold function based on polarization rotation in a single semiconductor optical amplifier

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    Optical threshold functions are a basic building block for alloptical signal processing, and this paper investigates a threshold function design reliant on a single active element. An optical threshold function based on nonlinear polarization rotation in a single semiconductor optical amplifier is proposed. It functions due to an induced modification of the birefringence of a semiconductor optical amplifier caused by an externally injected optical control signal. It is shown that switching from both the TE to the TM mode and vice versa is possible. The measured results are supported by simulation results based on the SOA rate equations. ©2007 Optical Society of Americ

    Kleinvoet: a Spatially-Distributed Temporally-Synchronised Infrasonic Recorder

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    We present the hardware design of a high-fidelity, low-cost infrasonic-capable (6 Hz) passive acoustic monitoring (PAM) prototype instrument. The device allows temporal synchronisation using a variety of global navigation satellite system (GNSS) constellations. This allows the recordings made by independent spatially-distributed nodes to be synchronised in time for acoustic monitoring and localisation using, for example, time difference of arrival (TDOA). Each node is capable of sampling at 24-bit resolution with a sampling frequency that is adjustable between 8 kHz and 192 kHz. Audio samples are stored locally on a microSD card, along with timestamp and location metadata

    Evolving Identification of Blood Cells Associated with Clinically Isolated Syndrome: Importance of Time since Clinical Presentation and Diagnostic MRI

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    It is not clear how the profile of immune cells in peripheral blood differs between patients with clinically isolated syndrome (CIS) and healthy controls (HC). This study aimed to identify a CIS peripheral blood signature that may provide clues for potential immunomodulatory approaches early in disease. Peripheral blood mononuclear cells (PBMCs) were collected from 18 people with CIS, 19 HC and 13 individuals with other demyelinating conditions (ODC) including multiple sclerosis (MS). Individuals with CIS separated into two groups, namely those with early (≤14 days post-diagnostic magnetic resonance imaging (MRI); n = 6) and late (≥27 days; n = 12) blood sampling. Transitional B cells were increased in the blood of CIS patients independently of when blood was taken. However, there were two time-dependent effects found in the late CIS group relative to HC, including decreased CD56bright NK cells, which correlated significantly with time since MRI, and increased CD141+ myeloid dendritic cell (mDC2) frequencies. Higher CD1c+ B cells and lower non-classical monocyte frequencies were characteristic of more recent demyelinating disease activity (ODC and early CIS). Analysing cell populations by time since symptoms (subjective) and diagnostic MRI (objective) may contribute to understanding CIS

    Access to chloroquine in patients with rheumatic and musculoskeletal diseases attending rheumatology outpatient clinics during the COVID-19 pandemic

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    Herbal medicines made from the bark of the Cinchona tree, and later quinine, have been widely used for centuries to treat medical conditions such as tropical malaria. More recently, chloroquine (CQ) and its synthetic derivatives have been used as antimalarials and to treat systemic lupus erythematosus, rheumatoid arthritis, and in the past 14 months or so, COVID-19 pneumonia. Anecdotal evidence and the erratic covering through social media of its potential efficacy in the treatment of COVID-19 pneumonia have resulted in the widespread off-label use of CQ in South Africa and worldwide. This study aimed to show that access to CQ as a chronic medication for rheumatic and musculoskeletal diseases was limited during the COVID-19 pandemic, and that this resulted in an increased incidence of flares in these patients, affecting their morbidity and potentially leading to mortality

    Characterization of gaseous and particulate phase polycyclica aromatic hydrocarbons emitted during preharvest burning of sugar cane in different regions of Kwa-Zulu Natal, South Africa

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    DATA AVAILABILITY : All associated data and calculation tools are available in the Supporting Information or directly from the corresponding author ( [email protected])Biomass burning is a significant anthropogenic source of air pollution, including the preharvest burning of sugar cane. These burn events result in atmospheric emissions, including semivolatile organic compounds, that may have adverse impacts on air quality and human health on a local, regional, and even a global scale. Gaseous and particulate polycyclic aromatic hydrocarbon (PAH) emissions from various sugar cane burn events in the province of Kwa-Zulu Natal in South Africa were simultaneously sampled using a portable denuder sampling technology, consisting of a quartz fiber filter sandwiched between two polydimethylsiloxane multichannel traps. Total gas and particle phase PAH concentrations ranged from 0.05 to 9.85 µg m–3 per individual burn event, and nine PAHs were quantified. Over 85% of all PAHs were found to exist in the gas phase, with smaller two- and three-ring PAHs, primarily naphthalene, 1-methyl naphthalene, and acenaphthylene, being the most dominant and causing the majority of variance between the burn sites. The PAH profiles differed between the different burn events at different sites, emphasizing the significant influence that the crop variety, prevailing weather conditions, and geographical location has on the type and number of pollutants emitted. The potential carcinogenicity of the PAH exposure was estimated based on toxic equivalency factors that showed varying risk potentials per burn event, with the highest value of 5.97 ng m–3. Environ Toxicol Chem 2023;42:778–792. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.Impala Platinum Ltd; Bundesministerium fĂĽr Bildung und Forschung; Helmholtz-Gemeinschaft; University of Pretoria; National Research Foundation.https://setac.onlinelibrary.wiley.com/journal/15528618Chemistr
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