33 research outputs found

    Lawson criterion for ignition exceeded in an inertial fusion experiment

    Get PDF
    For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion

    Time-varying managerial overconfidence and pecking order preference

    Get PDF
    This paper examines whether managerial overconfidence enhances or weakens pecking order preference. We construct time-varying managerial words-based (i.e. tone of Chairman’s Statement) and action-based (i.e. firm investment and directors’ trading) overconfidence measures. Both optimistic tone and industry-adjusted investment have significant and negative impacts on the pecking order coefficient in the Shyam-Sunder and Myers (J Financ Econ 51:219–244, 1999) regression framework. Overconfident managers tend to use more equity than debt to finance deficits. This new evidence is consistent with the proposition that overconfident managers who underestimate the riskiness of future earnings believe that their debt (equity) is undervalued (overvalued) and therefore prefer equity to debt financing. Thus, managerial overconfidence can lead to a reverse pecking order preference. We also find that managerial overconfidence significantly weakens pecking order preference especially in firms with high earnings volatility and small firms

    Mechanisms of action of systemic antibiotics used in periodontal treatment and mechanisms of bacterial resistance to these drugs

    Full text link
    corecore