Structure and entrainment in the plane of symmetry of a turbulent spot

Laser-Doppler velocity measurements in water are reported for the flow in the plane of symmetry of a turbulent spot. The unsteady mean flow, defined as an ensemble average, is fitted to a conical growth law by using data at three streamwise stations to determine the virtual origin in x and t. The two-dimensional unsteady stream function is expressed as ψ=U^2_∞tg(ξ,η) in conical similarity co-ordinates ζ = x/U_∞t and η = y/U_∞t. In these co-ordinates, the equations for the unsteady particle displacements reduce to an autonomous system. This system is integrated graphically to obtain particle trajectories in invariant form. Strong entrainment is found to occur along the outer part of the rear interface and also in front of the spot near the wall. The outer part of the forward interface is passive. In terms of particle trajectories in conical co-ordinates, the main vortex in the spot appears as a stable focus with celerity 0·77U_∞. A second stable focus with celerity 0·64U_∞ also appears near the wall at the rear of the spot. Some results obtained by flow visualization with a dense, nearly opaque suspension of aluminium flakes are also reported. Photographs of the sublayer flow viewed through a glass wall show the expected longitudinal streaks. These are tentatively interpreted as longitudinal vortices caused by an instability of Taylor-Görtler type in the sublayer

Local or state? Evidence on bank market size using branch prices

With the elimination of state laws against branching, banks can now compete across states. They are no longer limited to competing in local markets, defined by the Federal Reserve as metropolitan statistical areas or small groups of rural counties. Accordingly, a "local or state?" debate over market size is taking place among researchers, with some arguing that banking markets are statewide and others contending that they remain local. This article contributes to the debate with a novel, arguably better, indicator of market size: bank branch prices, as opposed to bank deposit rates. The pattern of branch price data suggests that banking markets are not necessarily local. The authors find that branch prices in ten northeast states over the 1990s are more closely correlated with bank concentration at the state level than at the local level, consistent with the "state-market" argument. However, they caution that the relationship is not completely robust; it depends partly on how the data are parsed. Further study using a larger set of branch price data will help settle the debate more definitively.Banking market ; Branch banks ; Bank competition

Risks, lessons learned, and secondary markets for greenhouse gas reductions

Collectively or individually, countries are likely to implement policies designed to limit greenhouse gas emissions. Experience from tradable quota schemes suggests that emissions trading could significantly reduce the costs of emission limits. The Kyoto Protocol provides the framework for a common trading mechanism for all countries - including countries that would not face immediate emission limits. Significantly, the Protocol places the responsibility for meeting emission limits with national governments. How policymakers choose to implement emission limits will significantly shape the incentives that drive evolving secondary markets for greenhouse-gas-based instruments. Potential market participants who were surveyed rate policy-related risk as higher than business-related risks. Domestic polices designed to reduce fragmentation in secondary markets, establish clear baselines and procedures, and strengthen host-country institutions can all help reduce the risks and costs of emission limits.Economic Theory&Research,Labor Policies,Payment Systems&Infrastructure,Environmental Economics&Policies,Health Economics&Finance,Health Economics&Finance,Environmental Economics&Policies,Carbon Policy and Trading,Energy and Environment,Economic Theory&Research

IDENTIFICATION OF MARKET POTENTIAL FOR PASTURE-RAISED PORK IN THE MISSISSIPPI DELTA OF ARKANSAS-1998

Agribusiness,

Studies on the biology of Phlebotomid sandflies

Imperial Users onl