1,768 research outputs found
Mapping Hydrogen in the Galaxy, Galactic Halo, and Local Group with ALFA: The GALFA-HI Survey Starting with TOGS
Radio observations of gas in the Milky Way and Local Group are vital for
understanding how galaxies function as systems. The unique sensitivity of
Arecibo's 305m dish, coupled with the 7-beam Arecibo L-Band Feed Array (ALFA),
provides an unparalleled tool for investigating the full range of interstellar
phenomena traced by the HI 21cm line. The GALFA (Galactic ALFA) HI Survey is
mapping the entire Arecibo sky over a velocity range of -700 to +700 km/s with
0.2 km/s velocity channels and an angular resolution of 3.4 arcminutes. We
present highlights from the TOGS (Turn on GALFA Survey) portion of GALFA-HI,
which is covering thousands of square degrees in commensal drift scan
observations with the ALFALFA and AGES extragalactic ALFA surveys. This work is
supported in part by the National Astronomy and Ionosphere Center, operated by
Cornell University under cooperative agreement with the National Science
Foundation.Comment: 3 pages, including 2 figure pages; figure image quality significantly
reduced; for full resolution version, please see
http://www.naic.edu/~gibson/cv/ao08_writeup.pdf ; to be published in AIP
conference proceedings for ``The Evolution of Galaxies through the Neutral
Hydrogen Window'', eds. R. Minchin & E. Momjia
Політична економія глобалізму і проблеми структурної модернізації національної економіки
У статті досліджується політична економія глобалізму як транзитивної системи зі своїми протиріччями та внутрішніми конфліктами. Розкриваються негативні наслідки і ризики функціонування системи силового глобалізму та його відмінності від об’єктивної природної глобалізації як форми глобальної інтеграції. Увага також акцентується на ролі держави в сучасних глобалізаційних процесах та на проблемі структурної модернізації національної економіки в умовах глобальної конкурентності. Проаналізовано основні вектори і характер глобальних зрушень на початку ХХІ ст. та спрогнозовано їх тенденції до середини століття.В статье исследуется политическая экономия глобализма как транзитивной системы со своими противоречиями и внутренними конфликтами. Раскрываются негативные последствия и риски функционирования системы силового глобализма и его отличия от объективной естественной глобализации как формы глобальной интеграции. Внимание также акцентируется на роли государства в современных глобализационных процессах и на проблеме структурной модернизации национальной экономики в условиях глобальной конкурентности. Проанализированы основные векторы и характер глобальных сдвигов в начале ХХІ века и спрогнозированы их тенденции к середине века.In this article the political economy of globalism as a transitive system with its contradictions and internal conflicts is investigated. Negative consequences and risks of functioning of power globalism system and its differences from objective natural globalization as form of global integration are covered. Attention is also accented on the role of the state in modern globalization processes and on the problem of structural modernization of national economy in the global competition conditions. Basic vectors and character of global changes at the beginning of the XXIst century are analysed and their tendencies to the middle of age are predicted
Fine-resolution mapping of microforms of a boreal bog using aerial images and waveform-recording LiDAR
Boreal bogs are important stores and sinks of atmospheric carbon whose surfaces are characterised by vegetation microforms. Efficient methods for monitoring their vegetation are needed because changes in vegetation composition lead to alteration in their function such as carbon gas exchange with the atmosphere. We investigated how airborne image and waveform-recording LiDAR data can be used for 3D mapping of microforms in an open bog which is a mosaic of pools, hummocks with a few stunted pines, hollows, intermediate surfaces and mud-bottom hollows. The proposed method operates on the bog surface, which is reconstructed using LiDAR. The vegetation was classified at 20 cm resolution. We hypothesised that LiDAR data describe surface topography, moisture and the presence and depth of field-layer vegetation and surface roughness; while multiple images capture the colours and texture of the vegetation, which are influenced by directional reflectance effects. We conclude that geometric LiDAR features are efficient predictors of microforms. LiDAR intensity and echo width were specific to moisture and surface roughness, respectively. Directional reflectance constituted 4-34 % of the variance in images and its form was linked to the presence of the field layer. Microform-specific directional reflectance patterns were deemed to be of marginal value in enhancing the classification, and RGB image features were inferior to LiDAR variables. Sensor fusion is an attractive option for fine-scale mapping of these habitats. We discuss the task and propose options for improving the methodology.Peer reviewe
SPEAR Far Ultraviolet Spectral Images of the Cygnus Loop
We present far-ultraviolet (FUV) spectral images, measured at C IV 1550, He
II 1640, Si IV+O IV] 1400, and O III] 1664, of the entire Cygnus Loop, observed
with the Spectroscopy of Plasma Evolution from Astrophysical Radiation (SPEAR)
instrument, also known as FIMS. The spatial distribution of FUV emission
generally corresponds with a limb-brightened shell, and is similar to optical,
radio and X-ray images. The features found in the present work include a
``carrot'', diffuse interior, and breakout features, which have not been seen
in previous FUV studies. Shock velocities of 140-160 km/s is found from a line
ratio of O IV] to O III], which is insensitive not only to resonance scattering
but also to elemental abundance. The estimated velocity indicates that the fast
shocks are widespread across the remnant. By comparing various line ratios with
steady-state shock models, it is also shown that the resonance scattering is
widespread.Comment: 13 pages, 3 figures, 1 table, accepted for publication in ApJ
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