Urbanization Sans Development?

From a theoretical standpoint, the question has to be asked whether or not the census should retain its present definition of urban areas. There is a need for a more meaningful integration of the structural, institutional and demographic criteria, if the term is to hold substantive meaning. In this light, this paper proposes that a two-tier urban definition be employed. The old definition should be retained for trend analysis purposes while a new definition that incorporates socioeconomic purposes should be instituted.urban management, population and family relation, urbanization, data and statistics

New Numerical Results Indicate a Half-Filling SU(4) Kondo State in Carbon Nanotubes

Numerical calculations simulate transport experiments in carbon nanotube quantum dots (P. Jarillo-Herrero et al., Nature 434, 484 (2005)), where a strongly enhanced Kondo temperature T_K ~ 8K was associated with the SU(4) symmetry of the Hamiltonian at quarter-filling for an orbitally double-degenerate single-occupied electronic shell. Our results clearly suggest that the Kondo conductance measured for an adjacent shell with T_K ~ 16K, interpreted as a singlet-triplet Kondo effect, can be associated instead to an SU(4) Kondo effect at half-filling. Besides presenting spin-charge Kondo screening similar to the quarter-filling SU(4), the half-filling SU(4) has been recently associated to very rich physical behavior, including a non-Fermi-liquid state (M. R. Galpin et al., Phys. Rev. Lett. 94, 186406 (2005)).Comment: 7 pages, 7 figure

The undersea habitat as a space station analog: Evaluation of research and training potential

An evaluation is given of the utility of undersea habitats for both research and training on behavioral issues relative to the space station. The feasibility of a particular habitat, La Chalupa, is discussed