6,794 research outputs found
The remotely piloted vehicle as an earth science research aircraft
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
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
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
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
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
The evolution of the solar neutrino flux which is described by the wave
function
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 and neutrinos
that could be detected by the terrestrial detectors.
The hypothesis of the -induced -decays is also discussed.
According to it, before the large SF, decreasing the -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 CaCO at lower mantle pressures
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
CaCO using a CO 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 carbon hybridized species at 40 GPa is
monoclinic with 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 CaCO. Nudged
elastic band (NEB) calculations are used to investigate the reaction mechanisms
between relevant crystal phases of CaCO and we postulate that the mineral
is capable of undergoing - hybridization change purely in the
structure forgoing the accepted post-aragonite structure.Comment: 12 pages, 8 figure
Implementation of a Wavefront-Sensing Algorithm
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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