21,869 research outputs found
A study of the usefulness of Skylab EREP data for earth resources studies in Australia
There are no author-identified significant results in this report
Structures in granitic bathyliths and associated foldbelts in relation to mineral resources
There are no author-identified significant results in this report
Cluster Winds Blow along Supercluster Axes
Within Abell galaxy clusters containing wide-angle tailed radio sources,
there is evidence of a ``prevailing wind'' which directs the WAT jets. We study
the alignment of WAT jets and nearby clusters to test the idea that this wind
may be a fossil of drainage along large-scale supercluster axes. We also test
this idea with a study of the alignment of WAT jets and supercluster axes.
Statistical test neighbours indicate no alignment of WAT jets towards nearest
clusters, but do indicate approximately 98% confidence in alignment with the
long axis of the supercluster in which the cluster lies. We find a preferred
scale for such superclusters of order 25 Mpc .Comment: Latex, 5 pages, with 5 postscript figures. To be published in MNRAS.
Slight revisions to coincide with journal text. Linked to color image at
http://kusmos.phsx.ukans.edu/~melott/images/A2634SUW.jp
The space station: Human factors and productivity
Human factor researchers and engineers are making inputs into the early stages of the design of the Space Station to improve both the quality of life and work on-orbit. Effective integration of the human factors information related to various Intravehicular Activity (IVA), Extravehicular Activity (EVA), and teletobotics systems during the Space Station design will result in increased productivity, increased flexibility of the Space Stations systems, lower cost of operations, improved reliability, and increased safety for the crew onboard the Space Station. The major features of productivity examined include the cognitive and physical effort involved in work, the accuracy of worker output and ability to maintain performance at a high level of accuracy, the speed and temporal efficiency with which a worker performs, crewmember satisfaction with their work environment, and the relation between performance and cost
Substructure in clusters containing wide-angle tailed radio galaxies. I. New redshifts
We present new redshifts and positions for 635 galaxies in nine rich clusters
containing Wide-Angle Tailed (WAT) radio galaxies. Combined with existing data,
we now have a sample of 18 WAT-containing clusters with more than 10 redshifts.
This sample contains a substantial portion of the WAT clusters in the VLA 20 cm
survey of Abell clusters, including 75% of WAT clusters in the complete survey
(z0.09. It is a representative sample
which should not contain biases other than selection by radio morphology. We
graphically present the new data using histograms and sky maps. A
semi-automated procedure is used to search for emission lines in the spectra in
order to add and verify galaxy redshifts. We find that the average apparent
fraction of emission line galaxies is about 9% in both the clusters and the
field. We investigate the magnitude completeness of our redshift surveys with
CCD data for a test case, Abell 690. This case indicates that our galaxy target
lists are deeper than the detection limit of a typical MX exposure, and they
are 82% complete down to R=19.0. The importance of the uniformity of the
placement of fibers on targets is posited, and we evaluate this in our
datasets. We find some cases of non-uniformities which may influence dynamical
analyses. A second paper will use this database to look for correlations
between the WAT radio morphology and the cluster's dynamical state.Comment: 15 pages, 5 figures, 7 tables. To appear in the Astronomical Journa
A Universal Temperature Profile for Galaxy Clusters
We investigate the predicted present-day temperature profiles of the hot,
X-ray emitting gas in galaxy clusters for two cosmological models - a current
best-guess LCDM model and standard cold dark matter (SCDM). Our
numerically-simulated "catalogs" of clusters are derived from high-resolution
(15/h kpc) simulations which make use of a sophisticated, Eulerian-based,
Adaptive Mesh-Refinement (AMR) code that faithfully captures the shocks which
are essential for correctly modelling cluster temperatures. We show that the
temperature structure on Mpc-scales is highly complex and non-isothermal.
However, the temperature profiles of the simulated LCDM and SCDM clusters are
remarkably similar and drop-off as
where and . This decrease
is in good agreement with the observational results of Markevitch et al.(1998)
but diverges, primarily in the innermost regions, from their fit which assumes
a polytropic equation of state. Our result is also in good agreement with a
recent sample of clusters observed by BeppoSAX though there is some indication
of missing physics at small radii (). We discuss the
interpretation of our results and make predictions for new x-ray observations
that will extend to larger radii than previously possible. Finally, we show
that, for , our universal temperature profile is consistent with
our most recent simulations which include both radiative cooling and supernovae
feedback.Comment: 8 pages, 6 figures, accepted for publication in ApJ, full-page
version of Fig. 2 at
http://www.cita.utoronto.ca/+AH4-cloken/PAPERS/UTP/f2.ep
Basic Psychological Need Satisfaction, Stress-Related Appraisals, and Dancers’ Cortisol and Anxiety Responses \ud
Self-determination theory (Deci & Ryan, 2000) posits basic psychological need satisfaction (BPNS) as essential for optimal functioning and health. Grounded in this framework, the current study examined the role of BPNS in dancers’ cognitive appraisals and hormonal and emotional responses to performance stress. Dancers reported their degree of BPNS 1 month before a solo performance. Threat and challenge appraisals of the solo were recorded 2 hr before the performance. Salivary cortisol and anxiety were measured 15 min before, and 15, 30, 45, and 60 min postperformance. Higher BPNS was associated with lower cortisol responses and anxiety intensity. Challenge appraisals mediated the association between BPNS and cortisol. Threat appraisals mediated the BPNS–anxiety intensity relationship. These findings point to the potential importance of performers’ BPNS for optimal emotional and hormonal homeostasis in performance conditions.\ud
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