4,177 research outputs found
Asymmetry measures for QSOs and companions
An asymmetry index is derived from ellipse-fitting to galaxy images, that
gives weight to faint outer features and is not strongly redshift-dependent.
These measures are made on a sample of 13 2MASS QSOs and their neighbour
galaxies, and a control sample of field galaxies from the same wide-field
imaging data. The QSO host galaxy asymmetries correlate well with visual tidal
interaction indices previously published. The companion galaxies have somewhat
higher asymmetry than the control galaxy sample, and their asymmetry is
inversely correlated with distance from the QSO. The distribution of
QSO-companion asymmetry indices is different from that for matched control
field galaxies at the significance level. We present the data and
discuss this evidence for tidal and other disturbances in the vicinity of QSOs.Comment: 13 pages, 2 tables, 4 figures; to appear in A
IMAGING OF LOW REDSHIFT QSOs WITH WFPC2
Observations with the PC2 CCD of the Hubble Space Telescope are described of
two bright QSOs of redshift ~0.3. 1403+434 is IR-bright and radio-quiet, and
2201+315 is radio-loud with extended structure. Exposures were taken with the
F702W and F555W filters. The images are deconvolved on their own and combined
with 0.5 arcsec ground-based images. Both host galaxies have the form and
luminosity of bright ellipticals, with nuclei of 1-2 times higher luminosity.
1403+434 is strongly interacting while 2201+315 may be in later stages of a
merger, both with a smaller companion. Both host galaxies have compact knots
and other small-scale peculiar features. Some general remarks are made based on
the total program sample of 6 QSOs.Comment: 11 pages, Plain TeX, 3 figures available from [email protected] To
appear in the Astronomical Journal
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Regimes of polymer behaviour in drop-on-demand ink-jetting
Three regimes of fast DoD jetting behaviour for solutions of mono-disperse linear polymers have been linked to the underlying polymer molecular chains and their fully extended length L in good solvents. This allows scaling laws in molecular weight to be predicted and applied to experimental jetting results from different DoD print heads. The higher extensional flows encountered in high speed jetting in viscous solvents can fully stretch linear molecules outside the nozzle, permitting jetting of higher polymer content than for purely elastic behaviour. These results are significant for DoD printing at raised jet speeds and will apply to any DoD print head jetting linear polymer solutions.This work was supported by EPSRC grant number RG5560
Algebraic Torsion in Contact Manifolds
We extract a nonnegative integer-valued invariant, which we call the "order
of algebraic torsion", from the Symplectic Field Theory of a closed contact
manifold, and show that its finiteness gives obstructions to the existence of
symplectic fillings and exact symplectic cobordisms. A contact manifold has
algebraic torsion of order zero if and only if it is algebraically overtwisted
(i.e. has trivial contact homology), and any contact 3-manifold with positive
Giroux torsion has algebraic torsion of order one (though the converse is not
true). We also construct examples for each nonnegative k of contact 3-manifolds
that have algebraic torsion of order k but not k - 1, and derive consequences
for contact surgeries on such manifolds. The appendix by Michael Hutchings
gives an alternative proof of our cobordism obstructions in dimension three
using a refinement of the contact invariant in Embedded Contact Homology.Comment: 53 pages, 4 figures, with an appendix by Michael Hutchings; v.3 is a
final update to agree with the published paper, and also corrects a minor
error that appeared in the published version of the appendi
Holding it all together? The management of supply cover in the teaching profession
There have for some years been concerns in Scotland about the availability of supply cover, the quality of supply teachers and the adequacy of support and development provided for them. This is a report of a study which focuses on the management of supply cover in Scotland. It presents an analysis of qualitative and quantitative data collected from education authorities, schools and supply teachers
The management of supply cover in the teaching profession
There have for some years been concerns in Scotland about the availability of supplycover, the quality of supply teachers, and the adequacy of support and developmentprovided for them. This Insighthighlights key findings from a study of the managementof supply cover in Scotland. The research was commissioned by the Scottish ExecutiveEducation Department in October 2002 to inform the development of guidelines
The Resolved Outer Population of NGC6822 with WFPC2
We present F336W (U), F439W (B), F555W (V), and F675W (R) Wide Field
Planetary Camera 2 (WFPC2) photometry of two outer regions of the Local Group
dwarf irregular galaxy NGC6822. The NE region is ~13 arcmin from the galaxy
centre, while the W region lies 10 arcmin out, and within the wispy low surface
brightness outer regions of the galaxy. The fields are not crowded and contain
few NGC 6822 stars. We discuss errors and uncertainties and find that the W
region contains a main sequence that extends to stars of about 2 solar masses,
with an age of about 200 Myr. The NE region has no main sequence or stars
younger than 1 Gyr, but does contain some luminous red stars that are not
matched in the W field. These stars are not clumped in the field. The results
suggest that the W region may be a trace of a tidal event that triggered the
current star-formation in this isolated galaxy.Comment: 12 pages including 2 tables, plus 4 figures (#1 omitted) To appear in
PAS
The sensory acceptance of fibre-enriched cereal foods:a meta-analysis
Improved understanding of the sensory responses to fibre fortification may assist manufacturers and health promotion efforts. The effects of fibre fortification (or modified ingredients) on sensory acceptability of baked cereal foods (bread, cookies, muffins) were estimated by linear random-effects meta-analysis of twenty eligible studies (869 panellists, 34% male). As little as 2 g per 100 g fortification caused moderateâlarge reductions in overall acceptability, flavour acceptability, and appearance acceptability in most items, with cookies most negatively affected. Fortification of base nonfortified foods with low initial acceptability improved acceptability; however, at higher basic levels, fortification lowered acceptability. Fortification improved texture acceptability of muffins and bread with low base acceptability, but lowered texture acceptability when base acceptability was high. Flavour improvement of muffins with fortification decreased with increasing base food acceptability. Fibre fortification of baked cereal foods lowers acceptability, but food format and base food acceptability affect the magnitude and direction of responses. Refining fibre fortification approaches could improve consumer uptake
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