[Review of] Milton J. Esman (Ed.), Ethnic Conflict in the Western World

Ethnic conflict has reemerged in the economic and political arenas of the western world, less between nation states, more within the boundaries of particular nations. The type of conflict that emerged in the United States during the 1950\u27s and 1960\u27s was racial, in sharp contrast to the ethnonationalist conflict in western Europe and Canada. The latter has a long history and has been shaped by cultural, linguistic, and religious differences. This conflict declined after World War II but is now back on the scene. The explanation of its return is one of the major purposes of this book. A second purpose is to raise the question of whether the Democratic Conflict Management model of consociationalism is a useful tool by which ethnic conflicts can be solved in a manner fair to all

Electrode erosion in arc discharges at atmospheric pressure

An experimental investigation was performed in an effort to measure and increase lifetime of electrodes in an arcjet thruster. The electrode erosion of various anode and cathode materials was measured after tests in an atmospheric pressure nitrogen arc discharge at powers less than 1 kW. A free-burning arc configuration and a constricted arc configuration were used to test the materials. Lanthanum hexaboride and thoriated tungsten had low cathode erosion rates while thoriated tungsten and pure tungsten had the lowest anode erosion rates of the materials tested. Anode cooling, reverse gas flow, and external magnetic fields were all found to reduce electrode mass loss

Canker disease in Corymbia calophylla (Marri) in the south west of Western Australia

Cankering of marri in the southern forests of Western Australia is causing concern as it is increasing considerably in severity and geographic range. The contribution of canker fungi to stem, branch and tree death has not been studied in detail, and the causal agent(s) is yet to be determined (1). This project examined disease incidence and associated pathogens

Quadratic Hedging of Basis Risk

This paper examines a simple basis risk model based on correlated geometric Brownian motions. We apply quadratic criteria to minimize basis risk and hedge in an optimal manner. Initially, we derive the Follmer-Schweizer decomposition of a European claim. This allows pricing and hedging under the minimal martingale measure, corresponding to the local risk-minimizing strategy. Furthermore, since the mean-variance tradeoff process is deterministic in our setup, the minimal martingale- and variance-optimal martingale measures coincide. Consequently, the mean-variance optimal strategy is easily constructed. Simple closed-form pricing and hedging formulae for put and call options are derived. Due to market incompleteness, these formulae depend on the drift parameters of the processes. By making a further equilibrium assumption, we derive an approximate hedging formula, which does not require knowledge of these parameters. The hedging strategies are tested using Monte Carlo experiments, and are compared with recent results achieved using a utility maximization approach.Option hedging; incomplete markets; basis risk; local risk minimization; mean-variance hedging

Three undescribed pathogenic Phytophthora taxa from the south-west of Western Australia

The Phytophthora culture collection of the Vegetation Health Service of the Department of Environment and Conservation of Western Australia (WA) has been re-evaluated using DNA sequencing (Burgess et al., 2009). This has revealed many undescribed taxa previously classified as known morpho-species, one of which has recently been described as P. multivora (Scott et al., 2009). The aim of this study was to describe three of these taxa, all of which occur in WA native ecosystems. They were compared with both the morphological species to which they are most similar and their closest phylogenetic relatives. In addition, the pathogenicity of these taxa was assessed in glasshouse trials

Hollow cathodes in high pressure arc discharges

An orified hallow cathode was tested at high pressure to improve lifetime and efficiency in arcjet thrusters. It is indicated that the arc would not operate with emission from the insert above 200 torr in nitrogen regardless of insert material, orifice diameter, or gas flow direction. Emission occurred from the insert in argon and xenon although it could not be ascertained whether diffuse or spot emission existed within the cathode. Over the extended range of configurations and operating parameters explored the desired diffuse emission mode could not be obtained at high enough pressures for orified hollow cathodes to operate in the range which is considered for arcjet applications

Ecology of Tridacna in Palau

Species composition, distribution, standing crop biomass, spawning, and growth rate of Tridacnidae clams were studied in Palau, Western Caroline Islands. The population was composed of six species: Tridama gigas, T. derasa, T. squamosa, T. maxima, T. crocea, and Hippopus hippopus. In random transects, T. crocea was the most frequent and abundant, while T. derasa and T. gigas made up the largest proportion of the standing crop biomass. Spawning was induced artificially in T. squamosa by addition of macerated gonad from one individual to an aquarium containing other individuals, but larval development was not observed. The growth rate of tagged Tridacnidae was slow and further study will be required before an estimate of biomass production can be derived

An Inexpensive Liquid Crystal Spectropolarimeter for the Dominion Astrophysical Observatory Plaskett Telescope

A new, inexpensive polarimetric unit has been constructed for the Dominion Astrophysical Observatory (DAO) 1.8-m Plaskett telescope. It is implemented as a plug-in module for the telescope's existing Cassegrain spectrograph, and enables medium resolution (R~10,000) circular spectropolarimetry of point sources. A dual-beam design together with fast switching of the wave plate at rates up to 100Hz, and synchronized with charge shuffling on the CCD, is used to significantly reduce instrumental effects and achieve high-precision spectropolarimetric measurements for a very low cost. The instrument is optimized to work in the wavelength range 4700 - 5300A to simultaneously detect polarization signals in the H beta line as well as nearby metallic lines. In this paper we describe the technical details of the instrument, our observing strategy and data reduction techniques, and present tests of its scientific performance.Comment: 32 pages, 15 figures. Accepted for publication in PAS