10,615 research outputs found

    Anomalous increase in nematic-isotropic transition temperature in dimer molecules induced by magnetic field

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    We have determined the nematic-isotropic transition temperature as a function of applied magnetic field in three different thermotropic liquid crystalline dimers. These molecules are comprised of two rigid calamitic moieties joined end to end by flexible spacers with odd numbers of methylene groups. They show an unprecedented magnetic field enhancement of nematic order in that the transition temperature is increased by up to 15K when subjected to 22T magnetic field. The increase is conjectured to be caused by a magnetic field-induced decrease of the average bend angle in the aliphatic spacers connecting the rigid mesogenic units of the dimers

    Provision of Music in Special Education. Executive Summary

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    Music Teachers’ Perceptions of, and approaches to,Creativity in the Greek-Cypriot Primary Education

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    TThe purpose of this study was to explore music teachers' perceptions of, and approaches to, creativity in Primary education. Even though teachers' perceptions on creativity have been investigated broadly and extensively, qualitative research on music teachers' beliefs nurturing the students' creativity in Primary education are less common. In the present paper, data were collected through in-depth interviews with 10 individuals in the Greek-Cypriot Primary Education. The results of this exploratory study indicated that activities should include the promotion of the students' self-action and autonomy, and the pedagogical initiatives that enable students to come up with original outputs in order to be creative. This understanding, in turn, provided the researchers with access to the teacher participants' perceptions of creativity: a multifaceted concept related to students' autonomy, initiative, and the application of imagination and unrestrained thinking to any musical activity. These findings offer some initial insights and are discussed with respect to their implications for policy and practice. Suggestions for future research are also made

    Applications of remote sensing to estuarine management

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    Projects for sewage outfall siting for pollution control in the lower Chesapeake Bay wetlands are reported. A dye-buoy/photogrammetry and remote sensing technique was employed to gather circulation data used in outfall siting. This technique is greatly favored over alternate methods because it is inexpensive, produces results quickly, and reveals Lagrangian current paths which are preferred in making siting decisions. Wetlands data were obtained by interpretation of color and color infrared photographic imagery from several altitudes. Historical sequences of photographs are shown that were used to document wetlands changes. Sequential infrared photography of inlet basins was employed to determine tidal prisms, which were input to mathematical models to be used by state agencies in pollution control. A direct and crucial link between remote sensing and management decisions was demonstrated in the various projects

    Seeding Rangeland.

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    STS-74/Mir photogrammetric appendage structural dynamics experiment

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    The Photogrammetric Appendage Structural Dynamics Experiment (PASDE) is an International Space Station (ISS) Phase-1 risk mitigation experiment. Phase-1 experiments are performed during docking missions of the U.S. Space Shuttle to the Russian Space Station Mir. The purpose of the experiment is to demonstrate the use of photogrammetric techniques for determination of structural dynamic mode parameters of solar arrays and other spacecraft appendages. Photogrammetric techniques are a low cost alternative to appendage mounted accelerometers for the ISS program. The objective of the first flight of PASDE, on STS-74 in November 1995, was to obtain video images of Mir Kvant-2 solar array response to various structural dynamic excitation events. More than 113 minutes of high quality structural response video data was collected during the mission. The PASDE experiment hardware consisted of three instruments each containing two video cameras, two video tape recorders, a modified video signal time inserter, and associated avionics boxes. The instruments were designed, fabricated, and tested at the NASA Langley Research Center in eight months. The flight hardware was integrated into standard Hitchhiker canisters at the NASA Goddard Space Flight Center and then installed into the Space Shuttle cargo bay in locations selected to achieve good video coverage and photogrammetric geometry

    On the Interpretation of Supernova Light Echo Profiles and Spectra

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    The light echo systems of historical supernovae in the Milky Way and local group galaxies provide an unprecedented opportunity to reveal the effects of asymmetry on observables, particularly optical spectra. Scattering dust at different locations on the light echo ellipsoid witnesses the supernova from different perspectives and the light consequently scattered towards Earth preserves the shape of line profile variations introduced by asymmetries in the supernova photosphere. However, the interpretation of supernova light echo spectra to date has not involved a detailed consideration of the effects of outburst duration and geometrical scattering modifications due to finite scattering dust filament dimension, inclination, and image point-spread function and spectrograph slit width. In this paper, we explore the implications of these factors and present a framework for future resolved supernova light echo spectra interpretation, and test it against Cas A and SN 1987A light echo spectra. We conclude that the full modeling of the dimensions and orientation of the scattering dust using the observed light echoes at two or more epochs is critical for the correct interpretation of light echo spectra. Indeed, without doing so one might falsely conclude that differences exist when none are actually present.Comment: 18 pages, 22 figures, accepted for publication in Ap

    Mode Combinations and International Operations: Theoretical Issues and an Empirical Investigation

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    An enduring characteristic of extant literature on foreign operation modes is its discrete choice approach, where companies are assumed to choose one among a small number of distinctive alternatives. • In this paper, detailed information about the operations of six Norwegian companies in three key markets (China, UK and USA) is used as the basis for an exploration of the extent to which, and how and why, companies combine clearly different foreign operation modes. We examine their use of foreign operation mode combinations within given value activities as well as within given countries. • The study reveals that companies tend to combine modes of operation; thereby producing unique foreign operation mode “packages” for given activities and/or countries, and that the packages are liable to be modified over time – providing a potentially important optional path for international expansion. • The data show considerable variation across cases; ranging from extensive use of mode combinations to a singular focus on a specific mode of operation. The study contributes to a refinement of our understanding of the path of internationalisation, and throws up a number of awkward theoretical questions about the process

    A Pre-Protostellar Core in L1551

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    Large field surveys of NH3, C2S, 13CO and C18O in the L1551 dark cloud have revealed a prolate, pre-protostellar molecular core (L1551-MC) in a relatively quiescent region to the northwest of the well-known IRS 5 source. The kinetic temperature is measured to be 9K, the total mass is ~2Msun, and the average particle density is 10^4-10^5 cm^(-3). L1551-MC is 2.25' x 1.11' in projection oriented at a position angle of 133deg. The turbulent motions are on the order of the sound speed in the medium and contain 4% of the gravitational energy, E_{grav}, of the core. The angular momentum vector is projected along the major axis of L1551-MC corresponding to a rotational energy of 2.5E-3(sin i)^(-2)|E_{grav}|. The thermal energy constitutes about a third of |E_{grav}| and the virial mass is approximately equal to the total mass. L1551-MC is gravitationally bound and in the absence of strong, ~160 microgauss, magnetic fields will likely contract on a ~0.3 Myr time scale. The line profiles of many molecular species suggest that the cold quiescent interior is surrounded by a dynamic, perhaps infalling envelope which is embedded within the ambient molecular gas of L1551.Comment: 27 pages, 7 figures, ApJ accepte
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