1,903 research outputs found
Disfavored Constitution, Passive Virtues? Linking State Constitutional Fiscal Limitations and Permissive Taxpayer Standing Doctrines
This Article contrasts the permissive state taxpayer standing doctrines in place in most states with the restrictive federal and state taxpayer standing rules applied in federal court. It proposes a new theory to explain this disparity, arguing that ubiquitous state constitutional fiscal restrictions, which specifically limit a state government’s ability to tax, spend, and borrow, are a primary impetus in the creation and development of liberal state taxpayer standing doctrines. The Article evaluates this novel hypothesis through an empirical-historical survey of the early state taxpayer standing decisions in every permissive jurisdiction and finds that these provisions are indeed involved in most cases and in most states. It concludes by discussing the implications of these results
The RMS Survey: Resolving kinematic distance ambiguities towards a sample of compact HII regions using HI absorption
We present high-resolution HI data obtained using the Australia Telescope
Compact Array to resolve the near/far distance ambiguities towards a sample of
compact HII regions from the Red MSX Source (RMS) survey. The high resolution
data are complemented with lower resolution archival HI data extracted from the
Southern and VLA Galactic Plane surveys. We resolve the distance ambiguity for
nearly all of the 105 sources where the continuum was strong enough to allow
analysis of the HI absorption line structure. This represents another step in
the determination of distances to the total RMS sample, which with over 1,000
massive young stellar objects and compact HII regions, is the largest and most
complete sample of its kind. The full sample will allow the distribution of
massive star formation in the Galaxy to be examined.Comment: Accepted by MNRAS. This paper consists of 15 pages and contains 10
figures and 5 table
The RMS Survey: 6 cm continuum VLA observations towards candidate massive YSOs in the northern hemisphere
(Abridged) Context: The Red MSX Source (RMS) survey is an ongoing
multi-wavelength observational programme designed to return a large,
well-selected sample of massive young stellar objects (MYSOs). We have
identified 2000 MYSO candidates located throughout the Galaxy by
comparing the colours of MSX and 2MASS point sources to those of known MYSOs.
Aims: To identify the populations of UCHII regions and PNe within the sample
and examine their Galactic distribution. Method: We have conducted high
resolution radio continuum observations at 6 cm towards 659 MYSO candidates in
the northern hemisphere (10\degr< l < 250\degr) using the VLA. In addition to
these targeted observations we present archival data towards a further 315 RMS
sources extracted from a previous VLA survey of the inner Galaxy. Results: We
find radio emission towards 272 (27% of the observed sample). Using
results from other parts of our multi-wavelength survey we separate these
RMS-radio associations into two distinct types of objects, classifying 51 as
PNe and a further 208 as either compact or UC HII regions. Using this well
selected sample of HII regions we estimate their Galactic scale height to be
0.6\degr. Conclusions: Using radio continuum and archival data we have
identified 79 PNe and 391 HII regions within the northern RMS catalogue. We
estimate the total fraction of contamination by PNe in the RMS sample is of
order 10%. The sample of HII regions is probably the best representation to
date of the Galactic population of HII regions as a whole.Comment: Accepted for publication in Astronomy and Astrophysics. 15 pages, 9
figures and 5 tables. Full versions of Tables 3, 4 and 5 and Figs. 2, 4 and 7
will only be available via CDS or the RMS website at
http:/www.ast.leeds.ac.uk/cgi-bin/RMS/RMS_VLA_IMAGES.cg
Characterisation of the Mopra Radio Telescope at 16--50 GHz
We present the results of a programme of scanning and mapping observations of
astronomical masers and Jupiter designed to characterise the performance of the
Mopra Radio Telescope at frequencies between 16-50 GHz using the 12-mm and 7-mm
receivers. We use these observations to determine the telescope beam size, beam
shape and overall telescope beam efficiency as a function of frequency. We find
that the beam size is well fit by / over the frequency range with a
correlation coefficient of ~90%. We determine the telescope main beam
efficiencies are between ~48-64% for the 12-mm receiver and reasonably flat at
~50% for the 7-mm receiver. Beam maps of strong HO (22 GHz) and SiO masers
(43 GHz) provide a means to examine the radial beam pattern of the telescope.
At both frequencies the radial beam pattern reveals the presence of three
components, a central `core', which is well fit by a Gaussian and constitutes
the telescopes main beam, and inner and outer error beams. At both frequencies
the inner and outer error beams extend out to approximately 2 and 3.4 times the
full-width half maximum of the main beam respectively. Sources with angular
sizes a factor of two or more larger than the telescope main beam will couple
to the main and error beams, and therefore the power contributed by the error
beams needs to be considered. From measurements of the radial beam power
pattern we estimate the amount of power contained in the inner and outer error
beams is of order one-fifth at 22 GHz rising slightly to one-third at 43 GHz.Comment: Accepted for publication in PAS
Characterizing fully principal congruence representable distributive lattices
Motivated by a recent paper of G. Gr\"atzer, a finite distributive lattice
is said to be fully principal congruence representable if for every subset
of containing , , and the set of nonzero join-irreducible
elements of , there exists a finite lattice and an isomorphism from the
congruence lattice of onto such that corresponds to the set of
principal congruences of under this isomorphism. Based on earlier results
of G. Gr\"atzer, H. Lakser, and the present author, we prove that a finite
distributive lattice is fully principal congruence representable if and
only if it is planar and it has at most one join-reducible coatom. Furthermore,
even the automorphism group of can arbitrarily be stipulated in this case.
Also, we generalize a recent result of G. Gr\"atzer on principal congruence
representable subsets of a distributive lattice whose top element is
join-irreducible by proving that the automorphism group of the lattice we
construct can be arbitrary.Comment: 20 pages, 8 figure
The RMS Survey: Distribution and properties of a sample of massive young stars
The Red MSX Source (RMS) survey has identified a large sample of massive
young stellar objects (MYSOs) and ultra compact (UC) HII regions from a sample
of ~2000 MSX and 2MASS colour selected sources. Using a recent catalogue of
molecular clouds derived from the Boston University-Five College Radio
Astronomy Observatory Galactic Ring Survey (GRS), and by applying a Galactic
scaleheight cut off of 120 pc, we solve the distance ambiguity for RMS sources
located within 18\degr 54\degr. These two steps yield kinematic
distances to 291 sources out of a possible 326 located within the GRS longitude
range. Combining distances and integrated fluxes derived from spectral energy
distributions, we estimate luminosities to these sources and find that > 90%
are indicative of the presence of a massive star. We find the completeness
limit of our sample is ~10^4 Lsun, which corresponds to a zero age main
sequence (ZAMS) star with a mass of ~12 Msun. Selecting only these sources, we
construct a complete sample of 196 sources. Comparing the properties of the
sample of young massive stars with the general population, we find the
RMS-clouds are generally larger, more massive, and more turbulent. We examine
the distribution of this sub-sample with respect to the location of the spiral
arms and the Galactic bar and find them to be spatially correlated. We identify
three significant peaks in the source surface density at Galactocentric radii
of approximately 4, 6 and 8 kpc, which correspond to the proposed positions of
the Scutum, Sagittarius and Perseus spiral arms, respectively. Fitting a scale
height to the data we obtain an average value of ~29+-0.5 pc, which agrees well
with other reported values in the literature, however, we note a dependence of
the scale height on galactocentric radius with it increases from 30 pc to 45 pc
between 2.5 and 8.5 kpc.Comment: Accepted for publication by MNRAS. Paper consists of 15 pages
including 12 figures and four tables. Full versions of Tables 2 and 3 will
only be available online. The resolution of Figure 9 has been reduced - a
full resolution version of the paper can be download from here:
http://www.ast.leeds.ac.uk/cgi-bin/RMS/RMS_PUBLICATIONS.cg
The Slope of the Near Infrared Extinction Law
We determine the slope of the near infrared extinction power law
(A) for 8 regions of the Galaxy between
l and . UKIDSS Galactic Plane Survey data are
compared, in colour-colour space, with Galactic population synthesis model data
reddened using a series of power laws and convolved through the UKIDSS filter
profiles. Monte Carlo simulations allow us to determine the best fit value of
and evaluate the uncertainty. All values are consistent with each
other giving an average extinction power law of
=2.14. This is much steeper than most laws previously
derived in the literature from colour excess ratios, which are typically
between 1.6 and 1.8. We show that this discrepancy is due to an inappropriate
choice of filter wavelength in conversion from colour excess ratios to
and that effective rather than isophotal wavelengths are more appropriate. In
addition, curved reddening tracks, which depend on spectral type and filter
system, should be used instead of straight vectors.Comment: Accepted by MNRAS: 11/08/09. 13 pages, 10 figures, 2 table
Probing discs around massive young stellar objects with CO first overtone emission
We present high resolution (R~50,000) spectroastrometry over the CO 1st
overtone bandhead of a sample of seven intermediate/massive young stellar
objects. These are primarily drawn from the red MSX source (RMS) survey, a
systematic search for young massive stars which has returned a large, well
selected sample of such objects. The mean luminosity of the sample is
approximately 5 times 10^4 L_\odot, indicating the objects typically have a
mass of ~15 solar masses. We fit the observed bandhead profiles with a model of
a circumstellar disc, and find good agreement between the models and
observations for all but one object. We compare the high angular precision
(0.2-0.8 mas) spectroastrometric data to the spatial distribution of the
emitting material in the best-fitting models. No spatial signatures of discs
are detected, which is entirely consistent with the properties of the
best-fitting models. Therefore, the observations suggest that the CO bandhead
emission of massive young stellar objects originates in small-scale disks, in
agreement with previous work. This provides further evidence that massive stars
form via disc accretion, as suggested by recent simulations.Comment: Accepted for publication in MNRA
The implications of sustainable development for airport duty-free business models
© HENRY STEWART PUBLICATIONS. This paper considers how the challenges underpinning sustainable development are likely to impact on duty-and tax-free retailing in airports and, by implication, in the entire aviation industry. The paper defines the role of retail as a vital source of airport revenues, before considering the carbon consequences of the sector’s incumbent business models. It finds that products taken onto aircraft increase aircraft weight and fuel burn and are a primary source of carbon emissions for duty-free retailers. The implications for the sector are discussed, and the potential for implementing more sustainable business models is presented. Here it is identified that the specific logistical, economic, and political constraints of operating in the airport make alternative business models difficult, if not impossible to implement. The specialisations that have helped this sector to flourish are constraining their ability to adapt to the climate challenge
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