Spinor-Like Hamiltonian for Maxwellian Optics

Background. Spinors are more special objects than tensors. Therefore spinors possess more properties than the more generic objects such as tensors. The group of Lorentz two-spinors is the covering group of the Lorentz group. Purpose. Since the Lorentz group is the symmetry group of Maxwell equations, it is reasonable to use Lorentz two-spinors and not tensors when writing the Maxwell equations. Method. We write the Maxwell equations using Lorentz two-spinors. Also a convenient representation of Lorentz two-spinors in terms of the Riemann-Silberstein complex vectors is used. Results. In the spinor formalism (in the representation of the Lorentz spinors and Riemann-Silberstein vectors) we have constructed the Hamiltonian of Maxwellian optics. With the use of spinors, the Maxwell equations take a form similar to the Dirac equation. Conclusions. For Maxwell equations in the Dirac-like form we can expand research methods by means of quantum field theory. In this form, the connection between the Hamiltonians of geometric, beam and Maxwellian optics is clearly visible

Catchment scale evaluation of trees, water and salt

Rising ground-waters and resultant salinity threaten agricultural land, conservation reserves and water resources in southern Australia. Although revegetation with woody plants is often considered as a strategy to restore catchment water balances, farm forestry has not been adopted in low-rainfall environments to the extent of that in high rainfall zones. Similarly, there is some conjecture that the proportion of revegetation needed to restore catchment water balances may be as high as 80%. The JVAP publication Trees, Water and Salt provides a set of guidelines for revegetation of farmland, however these have not been tested at the catchment scale in drier (<400 mm annual rainfall) environments that are representative of the wheat and wool-belt of much of southern Australia. Reforestation in these regions is often of limited scale, and thus at an inappropriate scale to assess catchment scale responses. This study measured the hydrologic response of an 80 ha catchment to partial reforestation, near Wickepin, Western Australia. This region, which has around 300 mm annual rainfall, has agriculture that comprises rotations of cropping and pastures. These trees were established using the procedures outlined in Trees, Water and Salt. An issue with dryland reforestation has been the lack of clear economic drivers. The emergence of markets for carbon sequestration and bioenergy from trees, in response to national climate change policies may increase the future rate of reforestation. Key issues include understanding the rates of both sequestration and biomass production in drier environments such as Wickepin and also how best to integrate reforestation with agricultural production. Of particular interest are the interaction of belts of trees with agriculture and the utilization of land that is poorly productive, such as that which has been affected by salinity

The identification of a species-specific antigen from Necator americanus.

A 17 kD protein of Necator americanus was isolated by SDS-PAGE and used to raise monospecific antisera in rabbits. ELISA and Western blotting against a range of parasite extracts demonstrated the species specificity of this protein. It is expressed at all stages of the life-cycle, appears to be accumulated through the larval stages to adulthood, and can be localized in the oesophageal glands and cuticle of the adult parasite. The possible nature and diagnostic potential of this protein is discussed

In vivo generation of transplantable human hematopoietic cells from induced pluripotent stem cells

10.1182/blood-2012-06-434407Blood12181255-1264BLOO