On the spectrum of a matrix model for the D=11 supermembrane compactified on a torus with non-trivial winding

The spectrum of the Hamiltonian of the double compactified D=11 supermembrane with non-trivial central charge or equivalently the non-commutative symplectic super Maxwell theory is analyzed. In distinction to what occurs for the D=11 supermembrane in Minkowski target space where the bosonic potential presents string-like spikes which render the spectrum of the supersymmetric model continuous, we prove that the potential of the bosonic compactified membrane with non-trivial central charge is strictly positive definite and becomes infinity in all directions when the norm of the configuration space goes to infinity. This ensures that the resolvent of the bosonic Hamiltonian is compact. We find an upper bound for the asymptotic distribution of the eigenvalues.Comment: 11 pages, LaTe

Cash Settlement of Lean Hog Futures Contracts Reexamined

In 1997 the Chicago Mercantile Exchange replaced its live hog futures contract with a cash settlement mechanism based on a Lean Hog Index. Although cash settlement was expected to increase the use of the contract as a hedging tool, producers and packers are concerned that convergence between cash and futures prices is not occurring and that the volatility of the lean hog contract basis has increased in recent years. The purpose of the paper is to reexamine cash settlement of lean hog futures contracts as a hedging tool, focusing on basis behavior and management of basis risk. We also investigate alternative hedging instruments that take into account location differences between regional cash prices and the CME lean hog index. Our results indicate that basis has widened and its variability prior to expiration has increased in the cash settlement period. Nevertheless, there is no evidence that ex-ante basis risk has increased, suggesting that the ability to forecast basis prior to expiration has not decreased with cash settlement. Our findings indicate that a contract on a regional basis can reduce producer price risk and may increase market returns. The benefits of a regional basis appear to accrue from providing the producer with an opportunity to manage the variability in returns associated with both the price level and basis.basis behavior, cash settlement, ex-ante basis risk, lean hogs futures contract, regional basis, Agricultural Finance,

Theory of extraordinary transmission of light through quasiperiodic arrays of subwavelength holes

By using a theoretical formalism able to work in both real and k-spaces, the physical origin of the phenomenon of extraordinary transmission of light through quasi-periodic arrays of holes is revealed. Long-range order present in a quasiperiodic array selects the wavevector(s) of the surface electromagnetic mode(s) that allows an efficient transmission of light through subwavelength holes.Comment: 4 pages, 4 figure

Agent-based simulation framework for airport collaborative decision making

Airport Collaborative Decision Making is based on information sharing. A better use of resources can be attained when the different stakeholders at airport operations share their more accurate and updated information. One of the main difficulties when dealing with this information sharing concept is the number of stakeholders involved and their different interest and behaviour: aircraft operators, ground handling companies, airport authority, air traffic control and the Central Flow Management Unit. It is paramount to quantify the benefit of an airport collaborative decision making strategy in order to involve all these different organisations. Simulations are required to analyse the overall system and its emerging behaviour. This paper presents the development and initial testing of an agent-based framework, which allows this behavioural analysis to be done. The simulator explicitly represents the different stakeholders involved in the A-CDM and the interactions between them from milestone 1 to 7. This framework allows independent gradual development of local behaviours and optimisation, and a gradual increase on complexity and fidelity on the simulations

Issues in Assessing Community Resources for the Leisure-Time Needs of the Elderly

The growth of leisure-time, following retirement, is potentially problematic for the elderly and can result in such adversities as depression, problem drinking, loneliness, and boredom. Leisure-time resources include recreation, education, volunteerism, training, voluntary associations, familialism, and solitary activities. The use of resources for leisure-time needs of the elderly are influenced by idiosyncratic differences; cultural background, financial resources, geographic variations; and the characteristics of programs and services. There is a need to better prepare individuals for the use of leisure-time. Each community must ensure that leisure-time resources exist and do not exclude any elderly from possible involvement, for either structural, programmatic, or philosophical reasons