Physics of the Pseudogap State: Spin-Charge Locking

The properties of the pseudogap phase above Tc of the high-Tc cuprate superconductors are described by showing that the Anderson-Nambu SU(2) spinors of an RVB spin gap 'lock' to those of the electron charge system because of the resulting improvement of kinetic energy. This enormously extends the range of the vortex liquid state in these materials. As a result it is not clear that the spinons are ever truly deconfined. A heuristic description of the electrodynamics of this pseudogap-vortex liquid state is proposed.Comment: Submitted to Phys Rev Letter

Review: Ocean Recovery: A Sustainable Future for Global Fisheries?

Revie

Notes on the Brown Widow Spider, Latrodectus Geometricus (Araneae: Theridiidae) in Brazil

Three species of the cosmopolitan genus Latrodectus were reported by Bucherl (1964) as occurring in Brazil: L. mactans mactans (Fabricius) from Recife, Pernambuco and from P6rto Alegre, Rio Grande do Sul; L. curacaviensis (Muller) from the beaches of Guanabara and Bahia; and L. geometricus C. L. Koch from the city of P6rto Alegre, Rio Grande do Sul and from the states of Minas Gerais, Bahia and Rio de Janeiro. Levi (1959) cited records of L. geometricus from the states of Paraiba, Pernarnbuco, Minas Gerais and Rio de Janeiro. In the United States L. geometricus has been reported as an introduced species from both Hawaii (Levi, 1967) and Florida (Levi and Levi, 1968). The present paper contains observations on L. geometricus in the state of Espirito Santo and in the city of Manaus, Amazonas, Brazil in 1969 and 1970

Bose Fluids Above Tc: Incompressible Vortex Fluids and "Supersolidity"

This paper emphasizes that non-linear rotational or diamagnetic susceptibility is characteristic of Bose fluids above their superfluid Tcs, and for sufficiently slow rotation or weak B-fields amounts to an incompressible response to vorticity. The cause is a missing term in the conventionally accepted model Hamiltonian for quantized vortices in the Bose fluid. The resulting susceptibility can account for recent observations of Chan et al on solid He, and Ong et al on cuprate superconductors

Dynamic testing of complex structures

Response of structure is determined under impulses large enough to create severe strains. Electrodynamic shaker can provide impulses to nearly any point on structure and can deliver repeated pulses of varying force and duration

Case study: design, operation and water quality management of a combined wet and dry pond system

Pond structures as cost-effective water treatment, storage and “source control” drainage techniques can be applied in order to reduce wastewater treatment costs, produce water for subsequent recycling and reduce the risk of downstream flooding. However, there is a need for detailed design, operation and maintenance data. The purpose of this study was to optimise design and operation guidelines, and to assess the water treatment potential of stormwater pond systems. Performance data (15 months) for a stormwater pond pilot plant were collected. The system is based on a combined silt trap, attenuation wet pond and dry pond system applied for drainage of roof water run-off from a single domestic property. United Kingdom Building Research Establishment and Construction Industry Research and Information Association, and German Association for Water, Wastewater and Waste design guidelines were tested. These design guidelines were insufficient because they do not consider local hydrological and soil conditions. The infiltration function for the dry pond is logarithmic and depends on the season. Furthermore, biochemical and physical algal control techniques were successfully applied, and passive water treatment of rainwater run-off with a wet pond was found to be sufficient. However, seasonal and diurnal variations of biochemical oxygen demand, dissolved oxygen and pH were recorded. Finally, capital and labour costs for small ponds are high