A unified projection formalism for the Al-Pd-Mn quasicrystal Xi-approximants and their metadislocations

The approximants xi, xi' and xi'_n of the quasicrystal Al-Mn-Pd display most interesting plastic properties as for example phason-induced deformation processes (Klein, H., Audier, M., Boudard, M., de Boissieu, M., Beraha, L., and Duneau, M., 1996, Phil. Mag. A, 73, 309.) or metadislocations (Klein, H., Feuerbacher, M., Schall, P., and Urban, K., 1999, Phys. Rev. Lett., 82, 3468.). Here we demonstrate that the phases and their deformed or defected states can be described by a simple projection formalism in three-dimensional space - not as usual in four to six dimensions. With the method we can interpret microstructures observed with electron microscopy as phasonic phase boundaries. Furthermore we determine the metadislocations of lowest energy and relate them uniquely to experimentally observed ones. Since moving metadislocations in the xi'-phase can create new phason-planes, we suggest a dislocation induced phase transition from xi' to xi'_n. The methods developed in this paper can as well be used for various other complex metallic alloys.Comment: 25 pages, 12 figure

Relative Returns on Equities in Pacific Basin Countries

We examine the factors that determine the differences in ex ante returns on equities in eleven Pacific Basin countries. Our concern is whether real return differentials are primarily caused by nominal return differentials or expected changes in real exchange rates. We find that nominal return differentials account for most of the difference, which suggests that either there is not free mobility of capital between the countries of our study or that there are significant differences in the riskiness of returns across countries. We do not find a significant relationship between the size of the return differentials and the flexibility of the nominal exchange rate.

Violating the Law of One Price: Should We Make a Federal Case Out of It?

We use new disaggregated data on consumer prices to determine why there is variability in prices of similar goods across U.S. cities. We address questions similar to those that have arisen in the international context: is this variability purely a result of market segmentation or do sticky nominal prices play a role? We also examine how the degree of tradability of a good influences price variability. Surprisingly, we find that variability is larger for traded-goods. We attribute this finding to greater price stickiness for non-traded goods. Distance between cities accounts for a significant amount of the variation in prices between pairs of cities. But we also find that nominal price stickiness plays an even more significant role.

Spin Hall effect in a two-dimensional electron gas in the presence of a magnetic field

We study the spin Hall effect of a two-dimensional electron gas in the presence of a magnetic field and both the Rashba and Dresselhaus spin-orbit interactions. We show that the value of the spin Hall conductivity, which is finite only if the Zeeman spin splitting is taken into account, may be tuned by varying the ratio of the in-plane and out-of-plane components of the applied magnetic field. We identify the origin of this behavior with the different role played by the interplay of spin-orbit and Zeeman couplings for in-plane and out-of-plane magnetic field components.Comment: 5 pages, 5 figures, submitte

Impact of Uncertainties in Hadron Production on Air-Shower Predictions

At high energy, cosmic rays can only be studied by measuring the extensive air showers they produce in the atmosphere of the Earth. Although the main features of air showers can be understood within a simple model of successive interactions, detailed simulations and a realistic description of particle production are needed to calculate observables relevant to air shower experiments. Currently hadronic interaction models are the main source of uncertainty of such simulations. We will study the effect of using different hadronic models available in CORSIKA and CONEX on extensive air shower predictions.Comment: 12 pages, 6 figures, to appear in the proceedings of International Conference on Interconnection between High Energy Physics and Astroparticle Physics: From Colliders to Cosmic Rays, Prague, Czech Republic, 7-13 Sep 200