3,817 research outputs found
Investment Prices and Exchange Rates: Some Basic Facts
This paper documents four basic facts about investment goods and investment prices. First, investment has a very significant nontradable component in the form of construction services. Second, distributions services (wholesaling, retailing, and transportation) are much less important for investment than for consumption. Third, the import content of investment is much larger than that of consumption. Finally, in the aftermath of three large devaluations, the rate of exchange rate pass-through is, perhaps not surprisingly, highest for imported equipment and lowest for construction services.
Distribution Costs and Real Exchange Rate Dynamics During Exchange-Rate-Based-Stabilizations
This paper studies the role played by the distribution sector in shaping the behavior of the real exchange rate during exchange-rate-based-stabilizations. We use data for the U.S. and Argentina to document the importance of distribution margins in retail prices and disaggregated price data to study price dynamics in the aftermath of Argentina's 1991 Convertibility plan. Distribution services require local labor and land so they drive a natural wedge between retail prices in different countries. We study in detail the impact of introducing a distribution sector in an otherwise standard model of exchange-rate-based-stabilizations. We show that this simple extension improves dramatically the ability of the model to rationalize observed real exchange rate dynamics.
Using patterns in the automatic marking of ER-Diagrams
This paper illustrates how the notion of pattern can be used in the automatic analysis and synthesis of diagrams, applied particularly to the automatic marking of ER-diagrams. The paper describes how diagram patterns fit into a general framework for diagram interpretation and provides examples of how patterns can be exploited in other fields. Diagram patterns are defined and specified within the area of ER-diagrams. The paper also shows how patterns are being exploited in a revision tool for understanding ER-diagrams
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EHMTI-0354. Abnormal expression of gene transcripts linked to inflammatory response in the periosteum of chronic migraine patients: implications to extracranial origin of headache
A catalogue of galaxies behind the southern Milky Way. - II. The Crux and Great Attractor regions (l = 289deg - 338deg)
In this second paper of the catalogue series of galaxies behind the southern
Milky Way, we report on the deep optical galaxy search in the Crux region
(289deg <= l <= 318deg and -10deg <= b <= 10deg) and the Great Attractor region
(316deg <= l <= 338deg and -10deg <= b <= 10deg). The galaxy catalogues are
presented, a brief description of the galaxy search given, as well as a
discussion on the distribution and characteristics of the uncovered galaxies. A
total of 8182 galaxies with major diameters D >= 0.2 arcmin were identified in
this ~850 square degree area: 3759 galaxies in the Crux region and 4423
galaxies in the Great Attractor region. Of the 8182 galaxies, 229 (2.8%) were
catalogued before in the optical (3 in radio) and 251 galaxies have a reliable
(159), or likely (92) cross-identification in the IRAS Point Source Catalogue
(3.1%). A number of prominent overdensities and filaments of galaxies are
identified. They are not correlated with the Galactic foreground extinction and
hence indicative of extragalactic large-scale structures. Redshifts obtained at
the South African Astronomical Observatory (SAAO) for 518 of the newly
catalogued galaxies in the Crux and Great Attractor regions (Fairall et al.
1998; Woudt et al. 1999) confirm distinct voids and clusters in the area here
surveyed. With this optical galaxy search, we have reduced the width of the
optical `Zone of Avoidance' for galaxies with extinction-corrected diameters
larger than 1.3 arcmin from extinction levels A_B >= 1.0 mag to A_B >= 3.0 mag:
the remaining optical Zone of Avoidance is now limited by |b| <= 3deg (see Fig.
16).Comment: 19 pages, 16 figures, accepted for publication in A&A. Tables will
shortly be available in electronic version at the CDS. Full resolution
(colour) copies of Figures 1, 2, 3 and 16 are available at
http://mensa.ast.uct.ac.za/~pwoud
The visibility of the Galactic bulge in optical surveys. Application to the Gaia mission
The bulge is a region of the Galaxy which is of tremendous interest for
understanding Galaxy formation. However, measuring photometry and kinematics in
it raises several inherent issues, like high extinction in the visible and
severe crowding. Here we attempt to estimate the problem of the visibility of
the bulge at optical wavelengths, where large CCD mosaics allow to easily cover
wide regions from the ground, and where future astrometric missions are
planned. Assuming the Besancon Galaxy model and high resolution extinction
maps, we estimate the stellar density as a function of longitude, latitude and
apparent magnitude and we deduce the possibility of reaching and measuring
bulge stars. The method is applied to three Gaia instruments, the BBP and MBP
photometers, and the RVS spectrograph. We conclude that, while in the BBP most
of the bulge will be accessible, in the MBP there will be a small but
significant number of regions where bulge stars will be detected and accurately
measured in crowded fields. Assuming that the RVS spectra may be extracted in
moderately crowded fields, the bulge will be accessible in most regions apart
from the strongly absorbed inner plane regions, because of high extinction, and
in low extinction windows like the Baades's window where the crowding is too
severe.Comment: 11 pages, 9 figures, accepted for publication in A&A, latex using A&A
macro
Color--Luminosity Relations for the Resolved Hot Stellar Populations in the Centers of M 31 and M 32
We present Faint Object Camera (FOC) ultraviolet images of the central
14x14'' of Messier 31 and Messier 32. The hot stellar population detected in
the composite UV spectra of these nearby galaxies is partially resolved into
individual stars, and their individual colors and apparent magnitudes are
measured. We detect 433 stars in M 31 and 138 stars in M 32, down to detection
limits of m_F275W = 25.5 mag and m_F175W = 24.5 mag. We investigate the
luminosity functions of the sources, their spatial distribution, their
color-magnitude diagrams, and their total integrated far-UV flux. Although M 32
has a weaker UV upturn than M 31, the luminosity functions and color-magnitude
diagrams of M 31 and M 32 are surprisingly similar, and are inconsistent with a
majority contribution from any of the following: PAGB stars more massive than
0.56 Msun, main sequence stars, or blue stragglers. Both the the luminosity
functions and color-magnitude diagrams are consistent with a dominant
population of stars that have evolved from the extreme horizontal branch (EHB)
along tracks with masses between 0.47 and 0.53 Msun. These stars are well below
the detection limits of our images while on the zero-age EHB, but become
detectable while in the more luminous (but shorter) AGB-Manque' and post-early
asymptotic giant branch (PEAGB) phases. The FOC observations require that only
a only a very small fraction of the main sequence population (2% in M 31 and
0.5% in M 32) in these two galaxies evolve though the EHB and post-EHB phases,
with the remainder evolving through bright PAGB evolution that is so rapid that
few if any stars are expected in the small field of view covered by the FOC.Comment: 35 pages, Latex. 19 figures. To appear in ApJ. Uses emulateapj.sty
and apjfonts.sty (included). Color plates distributed seperatedly: fig1.jpg
and fig2.jp
The Axis Ratio Distribution of Local and Distant Galaxies
Surface photometry from 16 HST/WFPC2 fields in the I(F814W) filter is used to
derive the distribution of apparent axis ratios for galaxies in progressively
fainter magnitude intervals for I<25. We assess the systematic and accidental
errors in ellipticity measurements as a function of image resolution and
signal-to-noise ratio, and statistically correct for the effect of cosmological
surface brightness dimming on our isophotal measurements. The axis ratio
distribution for the local galaxy population was computed using logR
measurements for 1569 RC3 galaxies with Bt<13 mag. Nonparametric tests are used
to show that our distant samples, in the redshift range 0.1<z<1.5, are not
statistically different from the local sample. We present image montages of
galaxies selected randomly from different axis ratio and apparent magnitude
ranges and discuss the evolutionary consequences of the lack of a strong
difference between the ellipticity distributions in near and far data sets.Comment: LaTex, 35 pages, 8 figures, accepted for Dec97 A
Experiments in the automatic marking of ER-Diagrams
In this paper we present an approach to the computer understanding of diagrams and show how it can be successfully applied to the automatic marking (grading) of student attempts at drawing entity-relationship (ER) diagrams. The automatic marker has been incorporated into a revision tool to enable students to practice diagramming and obtain feedback on their attempts
The Cuspy LINER Nucleus of the S0/a Galaxy NGC 2681
The nucleus of the bulge-dominated, multiply-barred S0/a galaxy NGC 2681 is
studied in detail, using high resolution Hubble Space Telescope FOC and NICMOS
imaging and FOS spectroscopy. The ionised gas central velocity dispersion is
found to increase by a factor ~2 when narrowing the aperture from R~1.5"
(ground) to R~0.1" (FOS). Dynamical modeling of these velocity dispersions
suggests that NGC 2681 does host a supermassive black hole (BH) for which one
can estimate a firm mass upper limit M_BH < 6*10^7 Solar Masses. This upper
limit is consistent with the relation between the central BH mass and velocity
dispersion M_BH - sigma known for other galaxies. The emission line ratios
place the nucleus of NGC 2681 among LINERs. It is likely that the emission line
region comes from a rather mild, but steady, feeding of gas to the central BH
in this galaxy. The inner stellar population lacks any measurable color
gradient (to a radius of 0.6 kpc) from the infrared to the ultraviolet,
consistently with FOC, FOS and IUE data, all indicating that this system
underwent a starburst ~1 Gyr ago that encompassed its whole interior, down to
its very center. The most likely source of such a widely-distributed starburst
is the dumping of tidally-extruded gas from a galaxy neighbor. If so, then NGC
2681 can be considered as the older brother of M82, seen face-on as opposed to
the edge-on view we have for M82.Comment: 25 pages, LaTeX, with 10 PostScript figures, to appear in The
Astrophysical Journa
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