5,919 research outputs found

    A central limit theorem for the zeroes of the zeta function

    Full text link
    On the assumption of the Riemann hypothesis, we generalize a central limit theorem of Fujii regarding the number of zeroes of Riemann's zeta function that lie in a mesoscopic interval. The result mirrors results of Soshnikov and others in random matrix theory. In an appendix we put forward some general theorems regarding our knowledge of the zeta zeroes in the mesoscopic regime.Comment: 22 pages. Incorporates referees suggestions. Contains minor corrections to published versio

    A statistical technique for determining rainfall over land employing Nimbus-6 ESMR measurements

    Get PDF
    An empirical method was employed to delineate synoptic scale rainfall over land utilizing Nimbus-6 ESMR measurements

    An assessment of health management and biosecurity procedures in marine fish farming in Spain

    Get PDF
    Marine fish farming in Spain has experienced problems of performance due to losses caused by infectious diseases. Biosecurity and health management are identified by the Food and Agriculture Organization (FAO) as current priorities for proper aquaculture governance. However, they both transcend the responsibility of farmers and require significant resources, concerted action and cooperation. This study presents the analysis of biosecurity practices on marine fish farms, through a questionnaire-based survey on biosecurity procedures and an analysis of health management practices for different stakeholders. The Strengths, Weaknesses, Opportunities, and Threats (SWOT) technique was implemented, which identified the important threats and weaknesses faced by the sector, such as the risk of direct disease transmission between farms, the high likelihood of importing diseases through juvenile shipments, the chronic lack of communication between stakeholders, and the deficient coordination of health strategies. Strengths included awareness of prevention measures and the availability of expertize of health experts at most levels. On the other hand, the availability of experts together with the need to adapt governance to the current production systems were seen as opportunities. Health management measures themselves were actually already found to be adapted to the type of production but they varied between companies (i.e. categorization and diagnosis of mortalities). Nevertheless, the quality of expertize along the value chain provided by private and public laboratories, research institutes, Health Protection Groups, companies and veterinarians was noteworthy. However, there was still a need for all stakeholders involved in marine fish health to improve diagnostics, provide epidemiological information, biosecurity and prevention measures, as well as to promote transparency for better health governance

    Traffic on complex networks: Towards understanding global statistical properties from microscopic density fluctuations

    Get PDF
    We study the microscopic time fluctuations of traffic load and the global statistical properties of a dense traffic of particles on scale-free cyclic graphs. For a wide range of driving rates R the traffic is stationary and the load time series exhibits antipersistence due to the regulatory role of the superstructure associated with two hub nodes in the network. We discuss how the superstructure affects the functioning of the network at high traffic density and at the jamming threshold. The degree of correlations systematically decreases with increasing traffic density and eventually disappears when approaching a jamming density Rc. Already before jamming we observe qualitative changes in the global network-load distributions and the particle queuing times. These changes are related to the occurrence of temporary crises in which the network-load increases dramatically, and then slowly falls back to a value characterizing free flow

    Rain observations in tropical storm Cora

    Get PDF
    Passive microwave observations were made in tropical storm Cora at 19.35 and 94GHz. These observations suggest that 94GHz is appropriate for mapping the extent of rain over either land or ocean backgrounds and that some rainfall intensity measurement is also possible

    Microwave radiometric observations near 19.35, 92 and 183 GHz of precipitation in tropical storm Cora

    Get PDF
    Observations of rain cells in the remains of a decaying tropical storm were made by Airborne Microwave Radiometers at 19.35,92 and three frequencies near 183 GHz. Extremely low brightness temperatures, as low as 140 K were noted in the 92 and 183 GHz observations. These can be accounted for by the ice often associated with raindrop formation. Further, 183 GHz observations can be interpreted in terms of the height of the ice. The brightness temperatures observed suggest the presence of precipitation sized ice as high as 9 km or more

    Analytical solution of the optimal laser control problem in two-level systems

    Full text link
    The optimal control of two-level systems by time-dependent laser fields is studied using a variational theory. We obtain, for the first time, general analytical expressions for the optimal pulse shapes leading to global maximization or minimization of different physical quantities. We present solutions which reproduce and improve previous numerical results.Comment: 12 pages, 2 figure

    Efficacy and safety of triple versus dual combination blood pressure-lowering drug therapy: a systematic review and meta-analysis of randomized controlled trials.

    Full text link
    BACKGROUND AND OBJECTIVES:Most patients with hypertension need at least two drugs to achieve goal blood pressure. This systematic review assessed efficacy and safety of triple versus dual combination therapy for the management of hypertension. METHODS:Publication databases, clinical trial registries and regulatory agency websites were searched until April 2018 for double-blind randomized controlled trials (RCTs) comparing triple with dual therapy of BP-lowering drugs, for at least 3 weeks, among patients with hypertension. Meta-analyses for efficacy and safety outcomes were performed using random-effects model. Regimen efficacy was predicted using the Therapeutic Intensity Score (TIS) and the Law et al. method (which predict dose doubling increases efficacy by 100% and around 20%, respectively), and compared with observed efficacy. RESULTS:Fourteen RCTs (11 457 participants) were included. Overall, triple compared with dual therapy reduced BP by 5.4/3.2 mmHg (P < 0.001), and improved BP control by 58 versus 45% [relative risk (RR) 1.33 (95% CI 1.25-1.41)], whereas incidence of withdrawals because of adverse events were 3.3 versus 3.4% [RR 1.24 (95% CI 1.00-1.54), P = 0.05]. Law et al.'s method was superior to TIS in predicting differences in efficacy between triple and dual therapies. For patients uncontrolled on submaximal dose dual therapy, adding a third drug achieved on average approximately four times more BP reduction than doubling the dose of dual therapy component drugs (6.0/3.6 versus 1.5/0.8 mmHg, respectively). CONCLUSION:Addition of a third drug is likely to be more efficacious without increasing adverse events, compared with increasing dose of existing dual therapy. Early use of triple therapy can significantly improve hypertension control
    • …
    corecore