358 research outputs found
Demographic composition and projections of car use in Austria
Understanding the factors driving demand for transportation in industrialised countries is important in addressing a range of environmental issues. Previous work has identified demographic factors as important influences on demand, in addition to economic factors. While some studies applied a detailed demographic composition to analyse past developments of transportation demand, or estimated parameters based on models that include demographic variables, projections for the future have never accounted for future compositional changes in the population. In this paper, we combine cross-sectional analysis of car use in Austria with detailed household projections to explore the sensitivity of projections of car use to the specific type of demographic disaggregation employed. We find that particular demographic characteristics of households can have important effects on aggregate demand through the combined effect of differences in demand across different types of households, and changes in the future composition of the population by household type. For example, the highest projected car use--an increase of about 20 per cent between 1996 and 2046--is obtained if we apply the value of car use per household to the projected numbers of households. However, if we apply a composition that differentiates households by size, age and sex of the household head, car use is projected to increase by less than 3 per cent during the same time period. These findings suggest that the inclusion of demographic factors in transportation demand modelling should extend beyond their use in historical decompositions and as controls in model parameter estimation to explicit consideration of future demographic changes.
Recommended from our members
The ACS Survey Of Globular Clusters. V. Generating A Comprehensive Star Catalog For Each Cluster
The ACS Survey of Globular Clusters has used Hubble Space Telescope's Wide-Field Channel to obtain uniform imaging of 65 of the nearest globular clusters to provide an extensive homogeneous data set for a broad range of scientific investigations. The survey goals required not only a uniform observing strategy, but also a uniform reduction strategy. To this end, we designed a sophisticated software program to process the cluster data in an automated way. The program identifies stars simultaneously in the multiple dithered exposures for each cluster and measures them using the best available point-spread function models. We describe here in detail the program's rationale, algorithms, and output. The routine was also designed to perform artificial-star tests, and we ran a standard set of similar to 10(5) tests for each cluster in the survey. The catalog described here will be exploited in a number of upcoming papers and will eventually be made available to the public via the World Wide Web.Astronom
The ACS survey of globular clusters. XIII. Photometric calibration in comparison with Stetson standards
In this study we compare the photometric data of 34 Milky Way globular
clusters, observed within the ACS Treasury Program (PI: Ata Sarajedini) with
the corresponding ground-based data, provided by the Photometric Standard Field
Catalogs of Stetson (2000, 2005). We focus on the transformation between the
HST/ACS F606W to V-band and F814W to I-band only. The goal is to assess the
validity of the filter transformation equations by Sirianni et al.(2005) with
respect to their dependence on metallicity, Horizontal Branch morphology, mass
and integrated (V-I) colour of the various globular clusters. Such a dependence
is expected due to the fact that the transformation equations are based on the
observations of only one globular cluster, i.e., NGC 2419. Surprisingly, the
correlation between offset and metallicity is found to be weak, with a low
level significance. The correlation between offset and Horizontal Branch
structure, as well as total cluster mass is still weaker. Based on the
available data we do not find the photometric offset to be linked to multiple
stellar populations, e.g., as found in NGC 0288, NGC 1851, and NGC 5139. The
results of this study show that there are small systematic offsets between the
transformed ACS- and observed ground based photometry, and that these are only
weakly correlated, if at all, with various cluster parameters and their
underlying stellar populations. As a result, investigators wishing to transform
globular cluster photometry from the Sirianni et al.(2005) ground-based V, I
system onto the Stetson (2000) system simply need to add 0.040 (+/-0.012) to
the V-band magnitudes and 0.047 (+/-0.011) to the I-band magnitudes. This in
turn means that the transformed ACS (V-I) colours match the ground-based values
from Stetson (2000) to within ~0.01 mag.Comment: 28 pages, 14 figures, accepted for publication in ApJ
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The ACS Survey Of Galactic Globular Clusters. VI. NGC 6366: A Heavily Stripped Galactic Globular Cluster
We have used observations obtained as part of the Hubble Space Telescope/ACS Survey of Galactic globular clusters (GCs) to construct a color-magnitude diagram for the bulge cluster, NGC 6366. The luminosity function derived from those data extends to M(F606W) similar to 9, or masses of similar to 0.3 M(circle dot). Unlike most GCs, the mass function peaks near the main-sequence turnoff with significantly fewer low-mass stars even after correction for completeness and mass segregation. Using a multimass King model, we extrapolate the global cluster behavior and find the global mass function to be poorly matched by a power law, with a particular deficit of stars with masses between 0.5 and 0.7 M(circle dot). We briefly discuss this interesting anomaly within the context of tidal stripping.NASA GO-10775, 5-26555Space Telescope Science InstituteInstituto de Astrofisica de Canarias P3-94Ministry of Education and Science of the Kingdom of Spain AYA-2008-67913Astronom
Reviews
The following publications have been reviewed by the mentioned authors;Getting Things Right Design and Realization by Adrian Marden, reviewed by Michael RobertsVisual Messages: An Introduction to Graphics by C. J. Breckon, L. J. Jones and C. E. Moorhouse, reviewed by John BaleErgonomics in the Computerized Office by Etienne Grandjean, reviewed by T. LawleyTeaching GCSE Craft, Design and Technology by David Rees, reviewed by Brian OppenheimComputers at Work by H. Scott, B. Frost, S. Alexander and G. Bowie, reviewed by S.R. St. J. NeillScience Report for Teachers: 10 Metals at age 15, reviewed by David BarlexThe Anti-Colouring Book by Susan Striker & Edward Kimmel, reviewed by Marshall HughesUnderstanding and Using Technology by A. Todd, C. McRory and D. Todd, reviewed by David Perry
The ACS Survey of Galactic Globular Clusters. VI. NGC 6366: A Heavily Stripped Galactic Globular Cluster
We have used observations obtained as part of the Hubble Space Telescope/ACS Survey of Galactic globular clusters (GCs) to construct a color-magnitude diagram for the bulge cluster, NGC 6366. The luminosity function derived from those data extends to M F606W ~ 9, or masses of ~0.3 M â. Unlike most GCs, the mass function peaks near the main-sequence turnoff with significantly fewer low-mass stars even after correction for completeness and mass segregation. Using a multimass King model, we extrapolate the global cluster behavior and find the global mass function to be poorly matched by a power law, with a particular deficit of stars with masses between 0.5 and 0.7 M â. We briefly discuss this interesting anomaly within the context of tidal stripping
The ACS Survey of Galactic Globular Clusters. viii. Effects of Environment on Globular Cluster Global Mass Functions
We have used observations obtained as part of the Hubble Space Telescope/ACS Survey of Galactic Globular Clusters to construct global present-day mass functions for 17 globular clusters utilizing multi-mass King models to extrapolate from our observations to the global cluster behavior. The global present-day mass functions for these clusters are well matched by power laws from the turnoff, â0.8 M â, to 0.2-0.3 M â on the lower main sequence. The slopes of those power-law fits, Îą, have been correlated with an extensive set of intrinsic and extrinsic cluster properties to investigate which parameters may influence the form of the present-day mass function. We do not confirm previous suggestions of correlations between Îą and either metallicity or Galactic location. However, we do find a strong statistical correlation with the related parameters central surface brightness, Îź V , and inferred central density, Ď0. The correlation is such that clusters with denser cores (stronger binding energy) tend to have steeper mass functions (a higher proportion of low-mass stars), suggesting that dynamical evolution due to external interactions may have played a key role in determining Îą. Thus, the present-day mass function may owe more to nurture than to nature. Detailed modeling of external dynamical effects is therefore a requisite for determining the initial mass function for Galactic globular clusters
The ACS Survey of Galactic Globular Clusters: M54 and Young Populations in the Sagittarius Dwarf Spheroidal Galaxy
We present new Hubble Space Telescope photometry of the massive globular
cluster M54 (NGC 6715) and the superposed core of the tidally disrupted
Sagittarius (Sgr) dSph galaxy as part of the ACS Survey of Galactic Globular
Clusters. Our deep (F606W~26.5), high-precision photometry yields an
unprecedentedly detailed color-magnitude diagram showing the extended blue
horizontal branch and multiple main sequences of the M54+Sgr system. The
distance and reddening to M54 are revised usingboth isochrone and main-sequence
fitting to (m-M)_0=17.27 and E(B-V)=0.15. Preliminary assessment finds the
M54+Sgr field to be dominated by the old metal-poor populations of Sgr and the
globular cluster. Multiple turnoffs indicate the presence of at least two
intermediate-aged star formation epochs with 4 and 6 Gyr ages and [Fe/H]=-0.4
to -0.6. We also clearly show, for the first time, a prominent, 2.3 Gyr old Sgr
population of near-solar abundance. A trace population of even younger (0.1-0.8
Gyr old), more metal-rich ([Fe/H]\sim0.6) stars is also indicated. The Sgr
age-metallicity relation is consistent with a closed-box model and multiple
(4-5) star formation bursts over the entire life of the satellite, including
the time since Sgr began disrupting.Comment: Accepted to ApJ Letter; 11 pages, 2 figures; figure 1 uploaded as
jpg; paper in ApJ format with full-resolution figures available at:
http://www.astro.ufl.edu/~ata/public_hstgc/paperIV/paperIV.p
Consciousness in Interdisciplinary Perspective: Discussions from the Hall Center for the Humanities Fall Faculty Colloquium 2011
This volume contains a collection of discussions from the 2011 Hall Center for the Humanities Fall Faculty Colloquium, University of Kansas, Lawrence, KS
The Grizzly, October 16, 1981
Long Range Improvements Planned ⢠Homecoming Coming Up ⢠Fraternity Hazing Topic of Next Forum ⢠Sadat: The Champion of Peace ⢠USGA Notes ⢠Procedure and Schedule for Spring Term Registration ⢠Frats Resume Reimert Cleanup ⢠Student Advising Program to be Revised Next Year ⢠Transplanted Texan: Evaluation of a Brown-noser ⢠Increased Internationalism Has Positive Effect on Campus ⢠Bad Weather Attendance Rules ⢠Homecoming Queen Candidates ⢠Community and Civilization Course ⢠Ursinus News Briefs: The law of the sea: is it a new threat to peace?; Exploring career options; CPAs to sponsor student manuscript contest ⢠Student Use of Helfferich Clarified ⢠New Medical Ethics Course Offered at Ursinus ⢠Field Hockey Winning Ways Return ⢠Booters Offense Sharp ⢠Bear Loss in Final Quarterhttps://digitalcommons.ursinus.edu/grizzlynews/1064/thumbnail.jp
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