6,794 research outputs found

    Supporting the assessment, learning and teaching needs of parttime teaching staff

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    The remotely piloted vehicle as an earth science research aircraft

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    A brief study was conducted at the Goddard Space Flight Center to identify existing remotely piloted vehicle (RPV) capabilities and to determine if the use of an RPV was advantageous and practical for Earth science investigations. A total of 17 instrument systems were identified. It was found that RPV's were considered especially valuable for dangerous missions, e.g., flights through volcano plumes and hurricanes, long duration profiles over inaccessible regions such as the Antarctic, and very low altitude ocean profiling missions

    Managing tribal assets: Developing long term strategic plans: Working paper series--98-01

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    As Native American tribes move toward self-determination with their governments and self-sufficiency of their peoples, they face daunting problems. Beginning from the status quo of unemployment rates ranging as high as 90%, concomitant social and health issues unseen elsewhere in the U.S., and limited financial assets, tribes need to develop long-term strategic plans. However, traditional economic development models and techniques are of little use in designing these plans. Additionally, some tribes are earning substantial financial assets through gaming operations. Nearly all tribes, however, still face the challenge of using their assets to build vibrant communities after many years of destitution. To this end, the development of a long-term strategic community development plan is called for. The National Executive Education Program for Native American Leadership (NEEPNAL) in conjunction with the Center for American Indian Economic Development (CAIED) has developed a method for aiding tribes to develop such plans. This paper addresses the multiple, difficult issues surrounding development of an effective long-term strategic planning process for productive uses of tribal assets. Further, the NEEPNAL/CAIED method for overcoming these difficulties is presented, with positive examples from tribal experience

    An Extraordinary Scattered Broad Emission Line in a Type 2 QSO

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    An infrared-selected, narrow-line QSO has been found to exhibit an extraordinarily broad Halpha emission line in polarized light. Both the extreme width (35,000 km/sec full-width at zero intensity) and 3,000 km/sec redshift of the line centroid with respect to the systemic velocity suggest emission in a deep gravitational potential. An extremely red polarized continuum and partial scattering of the narrow lines at a position angle common to the broad-line emission imply extensive obscuration, with few unimpeded lines of sight to the nucleus.Comment: 4 pages, 1 figure, to appear in the Astrophysical Journal Letter

    Embedding Participatory Governance

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    This symposium examines the challenges and opportunities of recent efforts at embedding participatory governance. It draws together original research that engages theoretically and empirically with some fundamental questions: •What are the challenges of embedding participatory governance in policy-making? •What happens when social movements have opportunities to shape the institutionalization of PG processes? Can they reanimate the radical potential of citizen participation for social transformation? •How can the tensions between the different demands of lay citizens, organized civil society, political parties, and public officials be managed? In this introductory article, we provide a definition of embeddedness, outlining its spatial, temporal, and practices dimensions, in so doing distinguishing embeddedness from institutionalization, with which it has often been used interchangeably. Our aim is to delineate the breadth of the concept, drawing together its many uses into a systematic framework that can both guide future research and practical experimentation. In particular, our hope is to turn more attention to the informal practices that are essential for embedding. The contributions to the symposium shift attention from institutional design to embedding dynamics and how these work to open or close spaces for meaningful citizen input

    The Polarized Spectrum of Apm 08279+5255

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    We report the discovery of significant linear polarization (p > 1%) in the hyperluminous z=3.87 BALQSO APM~08279+5255. The polarization spectrum is complex, with properties similar to those of other, lower redshift but more highly polarized BALQSOs. The resonance emission lines are unpolarized while the absorption troughs show polarization similar to or higher than the continuum. In particular, an apparent increase of polarization in the trough covering 1000-1030 angstroms (rest) supports the interpretation of this feature as a broad absorption component associated with OVI/Ly_beta local to the QSO, as opposed to an intervening damped Ly_alpha absorption system. The elevated polarization in some of the absorption features implies that we view the scattered (polarized) spectrum through a sightline with less absorbing material than the direct spectrum. Therefore, the complex structure of the polarization spectrum in this brilliant lensed BALQSO suggests that it will be an important laboratory for studying the structure of QSOs at high redshift.Comment: 8 pages, 1 figure. Accepted for publication in The Astrophysical Journal Letter

    Solar flares and their associated processes

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    The evolution of the solar neutrino flux which is described by the wave function ΨT=(νeL,νXL,ν‾eL,ν‾XL)\Psi^T=(\nu_{eL},\nu_{XL}, \overline{\nu}_{eL}, \overline{\nu}_{XL}) is examined. Our treatment of the problem holds for any standard model (SM) extensions possessing nonzero dipole magnetic and anapole moments. When the solar neutrino flux moves through the solar flare (SF) region in the preflare period, then it undergoes the additional (compared with the SM) resonance conversions. As a result, the weakening the electron neutrinos flux takes place. On the other hand, existence of the additional resonances lead to appearance of the ν‾eL\overline{\nu}_{eL} and ν‾XL\overline{\nu}_{XL} neutrinos that could be detected by the terrestrial detectors. The hypothesis of the νe\nu_e-induced β\beta-decays is also discussed. According to it, before the large SF, decreasing the β\beta-decay rate for some elements takes place. The possible influence of the electron antineutrino flux produced in the superflares on the regime of the hypothetical georeactor is considered.Comment: 11 pages. arXiv admin note: text overlap with arXiv:hep-ph/0401221 by other author

    Post-aragonite phases of CaCO3_{3} at lower mantle pressures

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    The stability, structure and properties of carbonate minerals at lower mantle conditions has significant impact on our understanding of the global carbon cycle and the composition of the interior of the Earth. In recent years, there has been significant interest in the behavior of carbonates at lower mantle conditions, specifically in their carbon hybridization, which has relevance for the storage of carbon within the deep mantle. Using high-pressure synchrotron X-ray diffraction in a diamond anvil cell coupled with direct laser heating of CaCO3_{3} using a CO2_{2} laser, we identify a crystalline phase of the material above 40 GPa −- corresponding to a lower mantle depth of around 1,000 km −- which has first been predicted by \textit{ab initio} structure predictions. The observed sp2sp^{2} carbon hybridized species at 40 GPa is monoclinic with P21/cP2_{1}/c symmetry and is stable up to 50 GPa, above which it transforms into a structure which cannot be indexed by existing known phases. A combination of \textit{ab initio} random structure search (AIRSS) and quasi-harmonic approximation (QHA) calculations are used to re-explore the relative phase stabilities of the rich phase diagram of CaCO3_{3}. Nudged elastic band (NEB) calculations are used to investigate the reaction mechanisms between relevant crystal phases of CaCO3_{3} and we postulate that the mineral is capable of undergoing sp2sp^{2}-sp3sp^{3} hybridization change purely in the P21/cP2_{1}/c structure −- forgoing the accepted post-aragonite PmmnPmmn structure.Comment: 12 pages, 8 figure

    Implementation of a Wavefront-Sensing Algorithm

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    A computer program has been written as a unique implementation of an image-based wavefront-sensing algorithm reported in "Iterative-Transform Phase Retrieval Using Adaptive Diversity" (GSC-14879-1), NASA Tech Briefs, Vol. 31, No. 4 (April 2007), page 32. This software was originally intended for application to the James Webb Space Telescope, but is also applicable to other segmented-mirror telescopes. The software is capable of determining optical-wavefront information using, as input, a variable number of irradiance measurements collected in defocus planes about the best focal position. The software also uses input of the geometrical definition of the telescope exit pupil (otherwise denoted the pupil mask) to identify the locations of the segments of the primary telescope mirror. From the irradiance data and mask information, the software calculates an estimate of the optical wavefront (a measure of performance) of the telescope generally and across each primary mirror segment specifically. The software is capable of generating irradiance data, wavefront estimates, and basis functions for the full telescope and for each primary-mirror segment. Optionally, each of these pieces of information can be measured or computed outside of the software and incorporated during execution of the software
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