6,898 research outputs found
Active Region Moss: Doppler Shifts from Hinode/EIS Observations
Studying the Doppler shifts and the temperature dependence of Doppler shifts
in moss regions can help us understand the heating processes in the core of the
active regions. In this paper we have used an active region observation
recorded by the Extreme-ultraviolet Imaging Spectrometer (EIS) onboard Hinode
on 12-Dec-2007 to measure the Doppler shifts in the moss regions. We have
distinguished the moss regions from the rest of the active region by defining a
low density cut-off as derived by Tripathi et al. (2010). We have carried out a
very careful analysis of the EIS wavelength calibration based on the method
described in Young et al. (2012). For spectral lines having maximum sensitivity
between log T = 5.85 and log T = 6.25 K, we find that the velocity distribution
peaks at around 0 km/s with an estimated error of 4-5 km/s. The width of the
distribution decreases with temperature. The mean of the distribution shows a
blue shift which increases with increasing temperature and the distribution
also shows asymmetries towards blue-shift. Comparing these results with
observables predicted from different coronal heating models, we find that these
results are consistent with both steady and impulsive heating scenarios.
However, the fact that there are a significant number of pixels showing
velocity amplitudes that exceed the uncertainty of 5 km s is suggestive
of impulsive heating. Clearly, further observational constraints are needed to
distinguish between these two heating scenarios.Comment: 21 pages (single column), 7 figures, Accepted for Publication in The
Astrophysical Journa
The cult of culture: An analysis and plan for teaching about organizational culture
Five general themes are prevalent in the literature of organizational culture: Meaning, structure, language, stability/instability, and reification. This thesis gives a broad general overview of the concept of culture as it relates to communication, analyzes the literature in terms of the above, and makes suggestions for its use to develop in students an understanding and appreciation of the concept of organizational culture. A prescriptive reading plan and a teaching plan are included to allow teachers to select topics that have importance either for themselves or their students
Protecting the Environment: Awareness and Responsibility
Protecting the environment is not only the right thing to do, it is the smart thing to do, in terms of both short-term and long term business goals. Green businesses can realize immediate financial benefits from environmental sustainability and energy conservation, and there are branding benefits associated with developing and maintaining a reputation for integrity and social responsibility. All participants first answered demographic questions and then responded to a ten-item questionnaire, which was a modified version of Simpson’s (1998) environmental awareness questionnaire. In conclusion, the study revealed gender, age, and political affiliation difference in environmental awareness
On Estimating the High-Energy Cutoff in the X-ray Spectra of Black Holes via Reflection Spectroscopy
The fundamental parameters describing the coronal spectrum of an accreting
black hole are the slope of the power-law continuum and the energy
at which it rolls over. Remarkably, this parameter can be accurately
measured for values as high as 1 MeV by modeling the spectrum of X-rays
reflected from a black hole accretion disk at energies below 100 keV. This is
possible because the details in the reflection spectrum, rich in fluorescent
lines and other atomic features, are very sensitive to the spectral shape of
the hardest coronal radiation illuminating the disk. We show that fitting
simultaneous NuSTAR (3-79 keV) and low-energy (e.g., Suzaku) data with the most
recent version of our reflection model RELXILL, one can obtain reasonable
constraints on at energies from tens of keV up to 1 MeV, for a source
as faint as 1 mCrab in a 100 ks observation.Comment: Accepted for publication in ApJL, 6 pages, 5 figure
Space environmental effects observed on the Hubble Space Telescope
The Hubble Space Telescope (HST) Repair Mission of December, 1993, was first and foremost a mission to improve the performance of the observatory. But for a specialized segment of the aerospace industry, the primary interest is in the return to Earth of numerous pieces of the HST hardware, pieces which have been replaced, repaired, improved, or superseded. The returned hardware is of interest because of the information it potentially carries about the effects of exposure to the space environment for three and a half years. Like the LDEF retrieval mission four years ago, the HST repair mission is of interest to many engineering disciplines, including all of the disciplines represented by the LDEF Special Investigation Groups (SIG's). There is particular interest in the evaluation of specific materials and systems in the returned components. Some coated surfaces have been processed with materials which are newer and still in use by, or under consideration for, other spacecraft in a variety of stages of development. Several of the systems are being returned because a specific failure or anomaly has been observed and thus there is, at the outset, a specific investigative trail that needs to be followed. These systems are much more complex than those flown on LDEF and, in two instances, comprised state-of-the-art science instruments. Further, the parts used in these systems generally were characterized more rigorously prior to flight than were those in the LDEF systems, and thus post flight testing may yield more significant results
Carboniferous of Eastern Kentucky - Stops 4-6.
This guidebook was produced for participants of the Sixth Gondwana Symposium held at the Institute of Polar Studies in August 1985. The trip traverses the highly scenic Appalachian Plateau. Enroute to eastern Kentucky, nonmarine sandstone, mudstone, coal, and limestone of the Upper Carboniferous to Permian (?) Dunkard Group, and Upper Carboniferous Monongahela and Conemaugh Formations will be examined in southern Ohio and western West Virginia. In eastern Kentucky, examination of the rocks will proceed up through the sequence starting with the Lower Carboniferous Berea Sandstone, a shallow marine deposit with abundant sedimentary structures; followed by the Borden Formation, which represents a prograding delta with shelf to basin facies including turbidites and abundant sedimentary structures; followed by the Borden Formation, which represents a prograding delta with shelf to basin facies including turbidites and abundant sedimentary structures, trace, and invertebrate fossils; the Slade Formation, a shallow carbonate sequence with paleokarst and paleosol features, and ending with the Upper Carboniferous Breathitt Formation, a marine to nonmarine sandstone, mudstone, and coal unit with famous coal ball localities
Emission Measure Distribution and Heating of Two Active Region Cores
Using data from the Extreme-ultraviolet Imaging Spectrometer aboard Hinode, we have studied the coronal plasma in the core of two active regions. Concentrating on the area between opposite polarity moss, we found emission measure distributions having an approximate power-law form EM/T(exp 2.4) from log T = 5.55 up to a peak at log T = 6.57. The observations are explained extremely well by a simple nanoflare model. However, in the absence of additional constraints, the observations could possibly also be explained by steady heating
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