Navstar GPS - Charting Aspects

The historical development of positioning in relation to the nautical chart is very briefly described. Present nautical charts are largely based on geodetic surveys which date from the 19th and early 20th century. This gave rise to the use of many local datums and there has been a need to provide the mariner with information to enable him to transfer his position from one chart to an adjacent one on a different datum. The sizes of discrepancies in position between various datums are given. The availability of the Global Positioning System (GPS) and the World Geodetic System 1984 (WGS 84) datum enables positioning on a single worldwide datum to become a reality. The important factors affecting the adoption of WGS 84 as the datum for nautical charts, namely data availability and the practical and political considerations, are discussed. The importance of the proper consideration of datum in relation to new developments in the use of nautical charts is also mentioned

Multi-site mean-field theory for cold bosonic atoms in optical lattices

We present a detailed derivation of a multi-site mean-field theory (MSMFT) used to describe the Mott-insulator to superfluid transition of bosonic atoms in optical lattices. The approach is based on partitioning the lattice into small clusters which are decoupled by means of a mean field approximation. This approximation invokes local superfluid order parameters defined for each of the boundary sites of the cluster. The resulting MSMFT grand potential has a non-trivial topology as a function of the various order parameters. An understanding of this topology provides two different criteria for the determination of the Mott insulator superfluid phase boundaries. We apply this formalism to $d$-dimensional hypercubic lattices in one, two and three dimensions, and demonstrate the improvement in the estimation of the phase boundaries when MSMFT is utilized for increasingly larger clusters, with the best quantitative agreement found for $d=3$. The MSMFT is then used to examine a linear dimer chain in which the on-site energies within the dimer have an energy separation of $\Delta$. This system has a complicated phase diagram within the parameter space of the model, with many distinct Mott phases separated by superfluid regions.Comment: 30 pages, 23 figures, accepted for publication in Phys. Rev.

The wallaby menace in the Kimberleys

Countless thousands of Sandy Wallabies (Macropus agilis) have long been a menace to the pastoral industry in the Kimberleys. These animals eat almost the same foods as the sheep and cattle and have substantially reduced the stock-carrying capacity of the river-frontage areas where they are found in the greatest numbers. Research into control methods was commenced in 1952 when Mr. L. A. Harrison undertook some investigations designed to ascertain the best line of approach to a poisoning campaign

Spin and Charge Texture around In-Plane Charge Centers in the CuO_2 planes

Recent experiments on La_2Cu_{1-x}Li_xO_4 show that although the doped holes remain localized near the substitutional Li impurities, magnetic order is rapidly suppressed. An examination of the spin texture around a bound hole in a CuO_2 plane shows that the formation of a skyrmion is favored in a wide range of parameters, as was previously proposed in the context of Sr doping. The spin texture may be observable by elastic diffuse neutron scattering, and may also have a considerable effect on NMR lineshapes.Comment: 4 pages, postscript file, hardcopy available upon request, to appear in PR

The role of pride in women with anorexia nervosa : a grounded theory study

Objective: Theory and clinical literature suggest that pride may play an important role in the maintenance of restrictive eating disorders. A grounded theory study explored experiences of, and reflections on, pride among women with a current or past diagnosis of anorexia nervosa. Design: This is a qualitative study using grounded theory. Method: Semi-structured interviews were conducted with 21 women recruited from an eating disorders unit in England, and from a UK self-help organization. Grounded theory from a constructivist lens was used. Analysis involved coding, constant comparison and memo-writing. Results: Pride evolves over the course of anorexia. Two overarching conceptual categories were identified: ‘Pride becoming intertwined with anorexia’ and ‘Pride during the journey towards recovery’. These categories encompassed different forms of pride: ‘alluring pride’, ‘toxic pride’, ‘pathological pride’, ‘anorexia pride’, ‘shameful pride’, ‘recovery pride’ and ‘resilient pride’. Initially, pride contributed to self-enhancement and buffered negative emotions. As the condition progressed, pride became a challenge to health and interfered with motivation to change. During recovery, perceptions of pride altered as a healthy approach to living ensued. Conclusions: The evolving nature of pride plays a central role in development, maintenance, and treatment of anorexia. Understanding of pride and its role in psychotherapeutic work with this client group may increase motivation to change and promote recovery. Future work should investigate if tackling pride in eating disorders increases treatment efficacy and reduces the risk of relapsing