56 research outputs found

    Chemical kinetic performance losses for a hydrogen laser thermal thruster

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77288/1/AIAA-25927-132.pd

    Tides in colliding galaxies

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    Long tails and streams of stars are the most noticeable upshots of galaxy collisions. Their origin as gravitational, tidal, disturbances has however been recognized only less than fifty years ago and more than ten years after their first observations. This Review describes how the idea of galactic tides emerged, in particular thanks to the advances in numerical simulations, from the first ones that included tens of particles to the most sophisticated ones with tens of millions of them and state-of-the-art hydrodynamical prescriptions. Theoretical aspects pertaining to the formation of tidal tails are then presented. The third part of the review turns to observations and underlines the need for collecting deep multi-wavelength data to tackle the variety of physical processes exhibited by collisional debris. Tidal tails are not just stellar structures, but turn out to contain all the components usually found in galactic disks, in particular atomic / molecular gas and dust. They host star-forming complexes and are able to form star-clusters or even second-generation dwarf galaxies. The final part of the review discusses what tidal tails can tell us (or not) about the structure and content of present-day galaxies, including their dark components, and explains how tidal tails may be used to probe the past evolution of galaxies and their mass assembly history. On-going deep wide-field surveys disclose many new low-surface brightness structures in the nearby Universe, offering great opportunities for attempting galactic archeology with tidal tails.Comment: 46 pages, 13 figures, Review to be published in "Tidal effects in Astronomy and Astrophysics", Lecture Notes in Physics. Comments are most welcom

    Review of STI-related ‘knowledge’ and ‘attitude’ studies: implications for teacher education in South Australia

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    Sexually transmitted infection (STI) rates are on the rise in South Australia as evident from a number of statistical reports. Pre-service teacher education forms the first step towards the professional development of teachers. Attributes such as knowledge and attitude are integral not only for teachers entering the profession but also for enhanced student learning outcomes. However, a review of the literature related to STI knowledge and attitudes of pre-service teachers reveal sufficient gaps in the knowledge and a lack of confidence of this cohort in addressing STI-related education. This is imperative towards the call for an effective teacher education in South Australia given the increased incidence of STIs in the state and the inconsistencies related to the inclusion of knowledge about STIs in pre-service teacher education undergraduate degrees
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