14,765 research outputs found
Which Survey Indicators Are Useful for Monitoring Consumption? Evidence fron European Countries
This paper assesses the information content of two survey indicators for consumption developments in the near future for eight European countries in the period 1985-1998. Empirical work on this topic typically focuses on consumer confidence, the perceptions of buyers of consumption goods. This paper examines whether perceptions of sellers of consumption goods, measured by retail trade surveys, may also improve short-term monitoring of consumption. We find that both consumer confidence and retailer confidence embody valuable information, when analyzed in isolation. For France, Italy and Spain we conclude that adding retail confidence does not improve the indicator model once consumer confidence has been included. For the UK the reverse case is obtained. For the remaining four countries we show that combining consumer sentiment and retail trade confidence into a composite indicator leads to optimal results. Our results suggest that incorporating information from retail trade surveys may offer significant benefits for the analysis of short-term prospects of consumption.consumption; consumer confidence; retail trade confidence; composite indicators
Deemo: a new technology for the fabrication of microstructures
The recent innovations in dry etching make it a promising technology for the fabrications of micromoulds. The high aspect ratios, directional freedom, low roughness, high etch rates and high selectivity with respect to the mask material allow a versatile fabrication process of micromoulds for subsequent electroplating and embossing, as is demonstrated with the DEEMO process. DEEMO is an English acronym and stands for Dry Etching, Electroplating and Moulding
Energy dissipation and scattering angle distribution analysis of the classical trajectory calculations of methane scattering from a Ni(111) surface
We present classical trajectory calculations of the rotational vibrational
scattering of a non-rigid methane molecule from a Ni(111) surface. Energy
dissipation and scattering angles have been studied as a function of the
translational kinetic energy, the incidence angle, the (rotational) nozzle
temperature, and the surface temperature. Scattering angles are somewhat
towards the surface for the incidence angles of 30, 45, and 60 degree at a
translational energy of 96 kJ/mol. Energy loss is primarily from the normal
component of the translational energy. It is transfered for somewhat more than
half to the surface and the rest is transfered mostly to rotational motion. The
spread in the change of translational energy has a basis in the spread of the
transfer to rotational energy, and can be enhanced by raising of the surface
temperature through the transfer process to the surface motion.Comment: 8 pages REVTeX, 5 figures (eps
Spectrophotometry of nearby field galaxies: the data
We have obtained integrated and nuclear spectra, as well as U, B, R surface
photometry, for a representative sample of 196 nearby galaxies. These galaxies
span the entire Hubble sequence in morphological type, as well as a wide range
of luminosities (M_B=-14 to -22). Here we present the spectrophotometry for
these galaxies. The selection of the sample and the U, B, R surface photometry
is described in a companion paper (Paper I). Our goals for the project include
measuring the current star formation rates and metallicities of these galaxies,
and elucidating their star formation histories, as a function of luminosity and
morphology. We thereby extend the work of Kennicutt (1992a) to lower luminosity
systems. We anticipate that our study will be useful as a benchmark for studies
of galaxies at high redshift.
We describe the observing, data reduction and calibration techniques, and
demonstrate that our spectrophotometry agrees well with that of Kennicutt. The
spectra span the range 3550--7250 A at a resolution (FWHM) of ~6 A, and have an
overall relative spectrophotometric accuracy of +/- 6 per cent. We present a
spectrophotometric atlas of integrated and nuclear rest-frame spectra, as well
as tables of equivalent widths and synthetic colors.
We study the correlations of galaxy properties determined from the spectra
and images. Our findings include: (1) galaxies of a given morphological class
display a wide range of continuum shapes and emission line strengths if a broad
range of luminosities are considered, (2) emission line strengths tend to in-
crease and continua tend to get bluer as the luminosity decreases, and (3) the
scatter on the general correlation between nuclear and integrated H_alpha
emission line strengths is large.Comment: Accepted for publication in ApJS (scheduled for Vol.127, 2000 March);
63 pages, LateX, 9 figures and 6 tables included, a spectrophotometric atlas
is provided as GIF images, fig 1 as a JPEG image, in a single tar-file; a
full 600 dpi version is available at http://www.astro.rug.nl/~nfgs
Mass loss out of close binaries. II
Liberal evolution of interacting binaries has been proposed previously by
several authors in order to meet various observed binary characteristics better
than conservative evolution does. Since Algols are eclipsing binaries the
distribution of their orbital periods is precisely known. The distribution of
their mass ratios contains however more uncertainties. We try to reproduce
these two distributions theoretically using a liberal scenario in which the
gainer star can lose mass into interstellar space as a consequence of its rapid
rotation and the energy of a hot spot. In a recent paper (Van Rensbergen et al.
2010, A&A) we calculated the liberal evolution of binaries with a B-type
primary at birth where mass transfer starts during core hydrogen burning of the
donor. In this paper we include the cases where mass transfer starts during
hydrogen shell burning and it is our aim to reproduce the observed
distributions of the system parameters of Algol-type semi-detached systems. Our
calculations reveal the amount of time that an Algol binary lives with a well
defined value of mass ratio and orbital period. We use these data to simulate
the distribution of mass ratios and orbital periods of Algols. Binaries with a
late B-type initial primary hardly lose any mass whereas those with an early B
primary evolve in a non-conservative way. Conservative binary evolution
predicts only ~ 12 % of Algols with a mass ratio q above 0.4. This value is
raised up to ~ 17 % using our scenario of liberal evolution, which is still far
below the ~ 45 % that is observed. Observed orbital periods of Algol binaries
larger than one day are faithfully reproduced by our liberal scenario. Mass
ratios are reproduced better than with conservative evolution, but the
resemblance is still poor.Comment: 11 pages, 6 figures, accepted for publication in A&A; accepted
versio
Graph-Based Shape Analysis Beyond Context-Freeness
We develop a shape analysis for reasoning about relational properties of data
structures. Both the concrete and the abstract domain are represented by
hypergraphs. The analysis is parameterized by user-supplied indexed graph
grammars to guide concretization and abstraction. This novel extension of
context-free graph grammars is powerful enough to model complex data structures
such as balanced binary trees with parent pointers, while preserving most
desirable properties of context-free graph grammars. One strength of our
analysis is that no artifacts apart from grammars are required from the user;
it thus offers a high degree of automation. We implemented our analysis and
successfully applied it to various programs manipulating AVL trees,
(doubly-linked) lists, and combinations of both
Precise Determination of |V{us}| from Lattice Calculations of Pseudoscalar Decay Constants
Combining the ratio of experimental kaon and pion decay widths, Gamma(K to mu
antineutrino{mu} (gamma)) / Gamma(pi to mu \antineutrino (gamma)), with a
recent lattice gauge theory calculation of f{K}/f{pi} provides a precise value
for the CKM quark mixing matrix element |V{us}|=0.2236(30) or if 3 generation
unitarity is assumed |V{us}|=0.2238(30). Comparison with other determinations
of that fundamental parameter, implications, and an outlook for future
improvements are given
Local and global properties of conformally flat initial data for black hole collisions
We study physical properties of conformal initial value data for single and
binary black hole configurations obtained using conformal-imaging and
conformal-puncture methods. We investigate how the total mass M_tot of a
dataset with two black holes depends on the configuration of linear or angular
momentum and separation of the holes. The asymptotic behavior of M_tot with
increasing separation allows us to make conclusions about an unphysical
``junk'' gravitation field introduced in the solutions by the conformal
approaches. We also calculate the spatial distribution of scalar invariants of
the Riemann tensor which determine the gravitational tidal forces. For single
black hole configurations, these are compared to known analytical solutions.
Spatial distribution of the invariants allows us to make certain conclusions
about the local distribution of the additional field in the numerical datasets
Decompositie van inkomensongelijkheid: Rusland 1992-2002
Introductie: Economen en sociale wetenschappers gebruiken kerngetallen om de inkomensongelijkheid van landen te beschrijven. In de meeste studies worden de Gini index, de leden van de “Generaliz Entropy” familie van indices (zoals de Theil en Atkinson coëfficiënten en de “Mean Logarithmic Deviation”), en de percentielratio’s P90/P10 en P75/P25 gebruikt. De waarden van al deze coëfficiënten vertellen iets over de inkomensongelijkheid op een bepaald moment of, via een tijdreeks van coëfficiënten, over trends in de inkomensongelijkheid.
Een van de centrale vragen bij de bestudering van inkomensongelijkheid betreft die naar de onderliggende factoren. Decompositie van inkomensongelijkheid kan daar op een antwoord geven. Decompositie van inkomensongelijkheid naar subgroepen in de populatie of naar bronnen van inkomen werd in het begin van de jaren ’80 geïntroduceerd in publicaties van Bourguignon (1979) en Shorrocks (1980; 1982; 1984). Zij lieten zien dat een aantal, maar niet alle maten voor ongelijkheid additief kunnen worden gedecomponeerd. Sinds die tijd is een groot aantal sociaal-economische studies met deze (inmiddels) standaard toepassingen verschenen...
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