1,770 research outputs found
On network modeling of manufacturing and related processes using GERT Summary report
Network modeling of manufacturing and related processes using Graphical Evaluation and Review Techniqu
Deceleration and Dispersion of Large-scale Coronal Bright Fronts
One of the most dramatic manifestations of solar activity are large-scale
coronal bright fronts (CBFs) observed in extreme ultraviolet (EUV) images of
the solar atmosphere. To date, the energetics and kinematics of CBFs remain
poorly understood, due to the low image cadence and sensitivity of previous EUV
imagers and the limited methods used to extract the features. In this paper,
the trajectory and morphology of CBFs was determined in order to investigate
the varying properties of a sample of CBFs, including their kinematics and
pulse shape, dispersion, and dissipation. We have developed a semi-automatic
intensity profiling technique to extract the morphology and accurate positions
of CBFs in 2.5-10 min cadence images from STEREO/EUVI. The technique was
applied to sequences of 171A and 195A images from STEREO/EUVI in order to
measure the wave properties of four separate CBF events. Following launch at
velocities of ~240-450kms^{-1} each of the four events studied showed
significant negative acceleration ranging from ~ -290 to -60ms^{-2}. The CBF
spatial and temporal widths were found to increase from ~50 Mm to ~200 Mm and
~100 s to ~1500 s respectively, suggesting that they are dispersive in nature.
The variation in position-angle averaged pulse-integrated intensity with
propagation shows no clear trend across the four events studied. These results
are most consistent with CBFs being dispersive magnetoacoustic waves.Comment: 15 pages, 18 figure
Behavioral activation for dementia caregivers: scheduling pleasant events and enhancing communications
published_or_final_versio
Development of the Risk Appraisal Measure: A Brief Screen to Identify Risk Areas and Guide Interventions for Dementia Caregivers
To develop and validate a brief screening measure for use in research, healthcare, and community settings to systematically assess well-being and identify needed areas of support for caregivers of patients with dementia. DESIGN : This study used data from Resources for Enhancing Alzheimer's Caregiver Health (REACH II), a multisite randomized clinical trial of a behavioral intervention designed to improve the quality of life of caregivers in multiple domains. SETTING : REACH II. PARTICIPANTS : Two hundred twelve Hispanic, 211 black, and 219 white family caregivers providing in-home care to patients with dementia. MEASUREMENT : Based on conceptual and psychometric analyses, a 16-item measure was developed that assesses six domains linked to caregiver risk and amenable to intervention: depression, burden, self-care and health behaviors, social support, safety, and patient problem behaviors. The reliability and validity of the instrument was evaluated with 642 dementia caregiver dyads from the REACH II program. RESULTS : The measure was found to have acceptable internal consistency for a multidimensional scale and similar measurement properties for each of the racial and ethnic groups. Concurrent validity was also demonstrated for the measure. CONCLUSION : The REACH Risk Appraisal Measure developed in this study shows promise as an assessment tool that can be used in research, clinical, and community settings to guide, prioritize, and target needed areas of support for caregivers of patients with dementia.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66234/1/j.1532-5415.2009.02260.x.pd
The destruction and survival of dust in the shell around SN 2008S
SN 2008S erupted in early 2008 in the grand design spiral galaxy NGC 6946.
The progenitor was detected by Prieto et al. in Spitzer Space Telescope images
taken over the four years prior to the explosion, but was not detected in deep
optical images, from which they inferred a self-obscured object with a mass of
about 10 Msun. We obtained Spitzer observations of SN 2008S five days after its
discovery, as well as coordinated Gemini and Spitzer optical and infrared
observations six months after its outburst.
We have constructed radiative transfer dust models for the object before and
after the outburst, using the same r^-2 density distribution of pre-existing
amorphous carbon grains for all epochs and taking light-travel time effects
into account for the early post-outburst epoch. We rule out silicate grains as
a significant component of the dust around SN 2008S. The inner radius of the
dust shell moved outwards from its pre-outburst value of 85 AU to a
post-outburst value of 1250 AU, attributable to grain vaporisation by the light
flash from SN 2008S. Although this caused the circumstellar extinction to
decrease from Av = 15 before the outburst to 0.8 after the outburst, we
estimate that less than 2% of the overall circumstellar dust mass was
destroyed.
The total mass-loss rate from the progenitor star is estimated to have been
(0.5-1.0)x10^-4 Msun yr^-1. The derived dust mass-loss rate of 5x10^-7 Msun
yr^-1 implies a total dust injection into the ISM of up to 0.01 Msun over the
suggested duration of the self-obscured phase. We consider the potential
contribution of objects like SN 2008S to the dust enrichment of galaxies.Comment: 9 pages, 7 figures, 3 tables. rv2. To appear in MNRA
Empathy, engagement, entrainment: the interaction dynamics of aesthetic experience
A recent version of the view that aesthetic experience is based in empathy as inner
imitation explains aesthetic experience as the automatic simulation of actions,
emotions, and bodily sensations depicted in an artwork by motor neurons in the brain. Criticizing the simulation theory for committing to an erroneous concept of empathy and failing to distinguish regular from aesthetic experiences of art, I advance an alternative, dynamic approach and claim that aesthetic experience is enacted and skillful, based in the recognition of others’ experiences as distinct from one’s own. In combining insights from mainly psychology, phenomenology, and cognitive science, the dynamic approach aims to explain the emergence of aesthetic experience in terms of the reciprocal interaction between viewer and artwork. I argue that aesthetic experience emerges by participatory sense-making and revolves around movement as a means for creating meaning. While entrainment merely plays a preparatory part in this, aesthetic engagement constitutes the phenomenological side of coupling to an artwork and provides the context for exploration, and eventually for moving, seeing, and feeling with art. I submit that aesthetic experience emerges from bodily and emotional engagement with works of art via the complementary processes of the perception–action and motion–emotion loops. The former involves the embodied
visual exploration of an artwork in physical space, and progressively structures and organizes visual experience by way of perceptual feedback from body movements made in response to the artwork. The latter concerns the movement qualities and shapes of implicit and explicit bodily responses to an artwork that cue emotion and thereby modulate over-all affect and attitude. The two processes cause the viewer to bodily and emotionally move with and be moved by individual works of art, and consequently to recognize another psychological orientation than her own, which explains how art can cause feelings of insight or awe and disclose aspects of life that are unfamiliar or novel to the viewer
Reconstructing the 3-D Trajectories of CMEs in the Inner Heliosphere
A method for the full three-dimensional (3-D) reconstruction of the
trajectories of coronal mass ejections (CMEs) using Solar TErrestrial RElations
Observatory (STEREO) data is presented. Four CMEs that were simultaneously
observed by the inner and outer coronagraphs (COR1 and 2) of the Ahead and
Behind STEREO satellites were analysed. These observations were used to derive
CME trajectories in 3-D out to ~15Rsun. The reconstructions using COR1/2 data
support a radial propagation model. Assuming pseudo-radial propagation at large
distances from the Sun (15-240Rsun), the CME positions were extrapolated into
the Heliospheric Imager (HI) field-of-view. We estimated the CME velocities in
the different fields-of-view. It was found that CMEs slower than the solar wind
were accelerated, while CMEs faster than the solar wind were decelerated, with
both tending to the solar wind velocity.Comment: 17 pages, 10 figures, 1 appendi
Large-scale Bright Fronts in the Solar Corona: A Review of "EIT waves"
``EIT waves" are large-scale coronal bright fronts (CBFs) that were first
observed in 195 \AA\ images obtained using the Extreme-ultraviolet Imaging
Telescope (EIT) onboard the \emph{Solar and Heliospheric Observatory (SOHO)}.
Commonly called ``EIT waves", CBFs typically appear as diffuse fronts that
propagate pseudo-radially across the solar disk at velocities of 100--700 km
s with front widths of 50-100 Mm. As their speed is greater than the
quiet coronal sound speed (200 km s) and comparable to the
local Alfv\'{e}n speed (1000 km s), they were initially
interpreted as fast-mode magnetoacoustic waves ().
Their propagation is now known to be modified by regions where the magnetosonic
sound speed varies, such as active regions and coronal holes, but there is also
evidence for stationary CBFs at coronal hole boundaries. The latter has led to
the suggestion that they may be a manifestation of a processes such as Joule
heating or magnetic reconnection, rather than a wave-related phenomena. While
the general morphological and kinematic properties of CBFs and their
association with coronal mass ejections have now been well described, there are
many questions regarding their excitation and propagation. In particular, the
theoretical interpretation of these enigmatic events as magnetohydrodynamic
waves or due to changes in magnetic topology remains the topic of much debate.Comment: 34 pages, 19 figure
Enhanced Star Formation in Narrow Line Seyfert 1 AGN revealed by Spitzer
We present new low resolution Spitzer mid-infrared spectroscopy of a sample
of 20 ROSAT selected local Narrow Line Seyfert 1 galaxies (NLS1s). We detect
strong AGN continuum in all and clear PAH emission in 70% of the sources. The
6.2 micron PAH luminosity spans three orders of magnitudes, from ~10^(39) erg/s
to ~10^(42) erg/s providing strong evidence for intense ongoing star formation
in the circumnuclear regions of these sources. Using the IRS/Spitzer archive we
gather a large number of additional NLS1s and their broad line counterparts
(BLS1s) and constructed NLS1 and BLS1 sub-samples to compare them in various
ways. The comparison shows a clear separation according to FWHM(H_beta) such
that objects with narrower broad H_beta lines are the strongest PAH emitters.
We test this division in various ways trying to remove biases due to luminosity
and aperture size. Specifically, we find that star formation activity around
NLS1 AGN is larger than around BLS1 of the same AGN luminosity. The above
result seems to hold over the entire range of distance and luminosity. Moreover
the star formation rate is higher in low black hole mass and high L/L_Edd
systems indicating that black hole growth and star formation are occurring
simultaneously.Comment: 30 pages, 11 figures, 4 tables. Now accepted in MNRA
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