1,248 research outputs found

    Knots and Random Walks in Vibrated Granular Chains

    Full text link
    We study experimentally statistical properties of the opening times of knots in vertically vibrated granular chains. Our measurements are in good qualitative and quantitative agreement with a theoretical model involving three random walks interacting via hard core exclusion in one spatial dimension. In particular, the knot survival probability follows a universal scaling function which is independent of the chain length, with a corresponding diffusive characteristic time scale. Both the large-exit-time and the small-exit-time tails of the distribution are suppressed exponentially, and the corresponding decay coefficients are in excellent agreement with the theoretical values.Comment: 4 pages, 5 figure

    Molecular Characterization of Plasmids Harbored by Actinomycetes Isolated From the Great Salt Plains of Oklahoma Using PFGE and Next Generation Whole Genome Sequencing

    Get PDF
    One of the unique features of actinomycetes, especially the genus Streptomyces, is the presence of linear plasmids. These range in size from 12 to 600 kb, and are often termed mega-plasmids. While many of the genes involved in secondary metabolite production reside in clusters on the chromosome, several studies have identified biosynthetic clusters on large linear plasmids that produce important secondary metabolites, including antibiotics. In this study, Pulse Field Gel Electrophoresis (PFGE) was used to screen 176 actinomycete isolates for the presence of plasmids; these bacterial strains were previously isolated from the Great Salt Plains of Oklahoma. Seventy-eight of the 176 actinomycete isolates (44%) contained plasmids. Several strains contained more than one plasmid, accounting for a total of 109 plasmids. Ten isolates showed extrachromosomal DNA larger than 200 kb, thus falling into the category of mega-plasmids. A subset of plasmids from 55 isolates was treated with S1 nuclease to determine topology; all plasmids examined appeared to be linear and ranged from ~55 to 400 kb. Eleven isolates were chosen for Whole Genome Next Generation Sequencing. From the 11 sequenced isolates, seven plasmids were partially assembled. While the majority of the genes identified on the plasmids coded for hypothetical proteins, others coded for general functions, stress response, and antibiotic and heavy metal resistance. Draft genome sequences of two mega-plasmid-bearing Streptomyces sp. strains, BF-3 and 4F, revealed the presence of genes involved in antibiotic production, antibiotic, and heavy metal resistance, osmoregulation, and stress response, which likely facilitate their survival in this extreme halophilic environment. To our knowledge, this is the first study to explore plasmids harbored by actinomycetes isolated from the Great Salt Plains of Oklahoma

    Annular electroconvection with shear

    Full text link
    We report experiments on convection driven by a radial electrical force in suspended annular smectic A liquid crystal films. In the absence of an externally imposed azimuthal shear, a stationary one-dimensional (1D) pattern consisting of symmetric vortex pairs is formed via a supercritical transition at the onset of convection. Shearing reduces the symmetries of the base state and produces a traveling 1D pattern whose basic periodic unit is a pair of asymmetric vortices. For a sufficiently large shear, the primary bifurcation changes from supercritical to subcritical. We describe measurements of the resulting hysteresis as a function of the shear at radius ratio η0.8\eta \sim 0.8. This simple pattern forming system has an unusual combination of symmetries and control parameters and should be amenable to quantitative theoretical analysis.Comment: 12 preprint pages, 3 figures in 2 parts each. For more info, see http://mobydick.physics.utoronto.c

    Target Mass Monitoring and Instrumentation in the Daya Bay Antineutrino Detectors

    Full text link
    The Daya Bay experiment measures sin^2 2{\theta}_13 using functionally identical antineutrino detectors located at distances of 300 to 2000 meters from the Daya Bay nuclear power complex. Each detector consists of three nested fluid volumes surrounded by photomultiplier tubes. These volumes are coupled to overflow tanks on top of the detector to allow for thermal expansion of the liquid. Antineutrinos are detected through the inverse beta decay reaction on the proton-rich scintillator target. A precise and continuous measurement of the detector's central target mass is achieved by monitoring the the fluid level in the overflow tanks with cameras and ultrasonic and capacitive sensors. In addition, the monitoring system records detector temperature and levelness at multiple positions. This monitoring information allows the precise determination of the detectors' effective number of target protons during data taking. We present the design, calibration, installation and in-situ tests of the Daya Bay real-time antineutrino detector monitoring sensors and readout electronics.Comment: 22 pages, 20 figures; accepted by JINST. Changes in v2: minor revisions to incorporate editorial feedback from JINS

    Development and Implementation of Integrated Road Traffic Injuries Surveillance – India (IRIS-India): A Protocol

    Get PDF
    Road traffic accidents stand as one of the leading causes of mortality and morbidity across the globe. The reasons for the high burden of road traffic injuries (RTIs) in developing countries are increasing in the number of motor vehicles, poor enforcement of traffic safety regulations, inadequacy of health infrastructure and poor transport facility. However, the systematic collection of road traffic data is not well developed in many developing countries including India and under-reporting of RTIs and deaths are common. Hence, surveillance of RTIs is recommended to assess the burden, to identify high-risk groups, to establish an association with probable risk factors and to plan interventions to control the RTIs. The broad objective of this study is to establish an electronic-based comprehensive and integrated RTI surveillance system, to assess the burden of RTIs, its risk factors and outcomes across rural and urban settings in India. This study with the support of the Indian Council of Medical Research (ICMR) is progressing in three cities (Chennai, Delhi and Jaipur) and two rural areas (Chittoor and Tehri-Garhwal). At each centre, major sources of data can be categorized under two categories including health facilities and community. In urban areas, one trauma centre, one private hospital and a community of 10000-population are included in the study. In rural areas, a district hospital, a private nursing home and two sub-centres areas of different primary health centres at each site are included for the surveillance. Passive surveillance is done at the trauma centres/district hospitals, while active surveillance is done in private hospitals/nursing homes, sub-centres and communities. Before establishing the surveillance system, situational analysis has been undertaken. Surveillance-related software was developed during the preparatory stage. This electronic surveillance platform allowed to gather data electronically across multiple sites. This internet-enabled surveillance platform has several modules to capture and analyse the data. The present study provides a model of surveillance including both passive and active surveillance to cover maximum number of RTIs. This study further provides the first comprehensive epidemiology of RTIs. The results of these studies will contribute to the setting of research and investment priorities to tackle the burden of RTIs

    Long-term survival of a woman with well differentiated papillary mesothelioma of the peritoneum: a case report and review of the literature

    Get PDF
    <p>Abstract</p> <p>Introduction</p> <p>Well-differentiated papillary mesothelioma of the peritoneum (WDPMP) is a rare subtype of epitheloid mesothelioma, which is usually seen in young women. WDPMP is generally considered of low malignant potential, however the long-term nature of the tumor remains poorly defined.</p> <p>Case presentation</p> <p>We describe the long-term follow-up of a 60-year-old woman of West African descent who has survived 24 years with WDPMP after receiving extensive local and systemic adjuvant chemotherapy. Her clinical course has included three exploratory laparotomies with intraperitoneal and intravenous chemotherapy over two decades. Her course was complicated by anthracycline-induced cardiomyopathy, for which she underwent an orthotopic heart transplant. Our patient is alive with stable radiological evidence of peritoneal disease, and continues to suffer from chronic abdominal pain.</p> <p>Conclusion</p> <p>No consensus exists regarding optimal treatment strategies for WDPMP. However, given the low malignant potential of the tumor, careful consideration should be made before proceeding with aggressive interventions. Further, long-term follow-up reports are required to fully characterize this tumor.</p

    First hint for CP violation in neutrino oscillations from upcoming superbeam and reactor experiments

    Full text link
    We compare the physics potential of the upcoming neutrino oscillation experiments Daya Bay, Double Chooz, NOvA, RENO, and T2K based on their anticipated nominal luminosities and schedules. After discussing the sensitivity to theta_{13} and the leading atmospheric parameters, we demonstrate that leptonic CP violation will hardly be measurable without upgrades of the T2K and NOvA proton drivers, even if theta_{13} is large. In the presence of the proton drivers, the fast track to hints for CP violation requires communication between the T2K and NOvA collaborations in terms of a mutual synchronization of their neutrino-antineutrino run plans. Even in that case, upgrades will only discover CP violation in a relatively small part of the parameter space at the 3 sigma confidence level, while 90% confidence level hints will most likely be obtained. Therefore, we conclude that a new facility will be required if the goal is to obtain a significant result with high probability.Comment: 27 pages, 12 figure
    corecore