3,418 research outputs found

    Comets in Australian Aboriginal Astronomy

    Full text link
    We present 25 accounts of comets from 40 Australian Aboriginal communities, citing both supernatural perceptions of comets and historical accounts of bright comets. Historical and ethnographic descriptions include the Great Comets of 1843, 1861, 1901, 1910, and 1927. We describe the perceptions of comets in Aboriginal societies and show that they are typically associated with fear, death, omens, malevolent spirits, and evil magic, consistent with many cultures around the world. We also provide a list of words for comets in 16 different Aboriginal languages.Comment: Accepted in the "Journal for Astronomical History & Heritage", 17 Pages, 6 Figures, 1 Tabl

    "Bridging the Gap" through Australian Cultural Astronomy

    Full text link
    For more than 50,000 years, Indigenous Australians have incorporated celestial events into their oral traditions and used the motions of celestial bodies for navigation, time-keeping, food economics, and social structure. In this paper, we explore the ways in which Aboriginal people made careful observations of the sky, measurements of celestial bodies, and incorporated astronomical events into complex oral traditions by searching for written records of time-keeping using celestial bodies, the use of rising and setting stars as indicators of special events, recorded observations of variable stars, the solar cycle, and lunar phases (including ocean tides and eclipses) in oral tradition, as well as astronomical measurements of the equinox, solstice, and cardinal points.Comment: Proceedings of IAU Symposium 278, Oxford IX International Symposium on Archaeoastronomy, International Society for Archaeoastronomy & Astronomy in Culture (ISAAC), held in Lima, Peru, 5-9 January 2011. 9 pages, 4 images, 1 table (Accepted

    Selection principles and pattern formation in fluid mechanics and nonlinear shell theory

    Get PDF
    Research accomplishments are summarized and publications generated under the contract are listed. The general purpose of the research was to investigate various symmetry breaking problems in fluid mechanics by the use of structure parameters and selection principles. Although all of the nonlinear problems studied involved systems of partial differential equations, many of these problems led to the study of a single nonlinear operator equation of the form F(w, lambda, gamma) = 0, (w is an element of H), (lambda is an element of R1), (gamma is an element of R1). Instead of varying only the load parameter lambda, as is often done in the study of such equations, one of the main ideas used was to vary the structure parameter gamma in such a way that stable solutions were obtained. In this way one determines detailed stability results by making use of the structure of the model equations and the known physical parameters of the problem. The approach was carried out successfully for Benard-type convection problems, Taylor-like problems for short cylinders, rotating Couette-Poiseuille channel flows, and plane Couette flows. The main focus of the research was on wave theory of vortex breakdown in a tube. A number of preliminary results for inviscid axisymmetric flows were obtained

    Hubbard Model with Luscher fermions

    Full text link
    First applications of the new algorithm simulating dynamical fermions are reported. The method reproduces previous results obtained with different techniques.Comment: talk presented at the XII International Symposium LATTICE94, Bielefeld, Germany, September 1994, to appear in the Proceedings. 3 pages, LATEX, required Elsevier espcrc2.sty style file is attached at the end of this LATEX text. Postscript figures included in the latex document with the epsf facilit

    Wurdi Youang: an Australian Aboriginal stone arrangement with possible solar indications

    Full text link
    Wurdi Youang is an egg-shaped Aboriginal stone arrangement in Victoria, Australia. Here we present a new survey of the site, and show that its major axis is aligned within a few degrees of east-west. We confirm a previous hypothesis that it contains alignments to the position on the horizon of the setting sun at the equinox and the solstices, and show that two independent sets of indicators are aligned in these directions. We show that these alignments are unlikely to have arisen by chance, and instead the builders of this stone arrangement appear to have deliberately aligned the site on astronomically significant positions.Comment: Accepted by Rock Art Researc

    Hubbard Model with Luscher fermions - a progress report

    Full text link
    Some modifications of the Luscher algorithm, which reduce the autocorelation time, are proposed and tested.Comment: 3 pages, uuencoded gzipped Postscript, contribution to Lattice 9

    Intra-industry trade between The United States and México: 1993-1998

    Get PDF
    This paper examines changes in intra-industry trade, IIT, in manufactured goods between the US and Mexico over the first five years of the North American Free Trade Agreement. Most industries experienced large increases in, IIT. An examination of various indexes of intra-industry specialization indicates that few industries in either country are candidates for significant adjustment problems. These findings should lessen opposition to greater regional economic integration in the Western Hemisphere

    Kinetic tetrazolium microtiter assay

    Get PDF
    A method for conducting an in vitro cell assay using a tetrazolium indicator is disclosed. The indicator includes a nonionic detergent which solubilizes a tetrazolium reduction product in vitro and has low toxicity for the cells. The incubation of test cells in the presence of zolium bromide and octoxynol (TRITON X-100) permits kinetics of the cell metabolism to be determined

    Lunar and planetary studies

    Get PDF
    This grant supports the core program in planetary astronomy at Caltech. The research includes observations in the IR, sub-mm, mm and cm wavelengths at national and Caltech observatories with a strong emphasis on integrating the observations with spacecraft data and with models of atmospheric structure, dynamics and chemistry. Muhleman's group made extensive observations of Saturn, Uranus and Neptune which are being interpreted in terms of deep atmospheric structures which are obvious in the 2 and 6 cm maps of Saturn and Uranus. The microwave measurements are one of the few sources of information below the 2 bar level. Goldreich is investigating the dynamics of narrow rings with postdoctoral fellow, Pierre-Yves Longaretti. Their work has focused on the role of collisional stresses on the precession of the rings, since the Voyager radio science results imply that the previous model based on the ring's self-gravity is not the entire story. In addition Borderies, Goldreich and Tremaine have completed an investigation of the dynamics of the Encke division in Saturn's A ring
    corecore