596 research outputs found
Welfare Benefits And Work Incentives: The Distribution Of Net Replacement Rates In Europe Using A Cross Country Microsimulation Model, EUROMOD
This paper considers the methodology of measuring replacement rates, comparing simulation based approaches, which simulate replacement rates for a representative sample of the population, with other approaches that simulate replacement rates for typical families or are entirely based on recorded household data. We emphasise the advantages of the first method. Utilising a cross-country microsimulation model for Europe, EUROMOD, we generate the distribution of replacement rates for four European countries, Denmark, France, Spain and the UK. In particular we show the important role of household composition and the presence of other household members' incomes in preserving the standard of living while out of work. We argue that, given this strong influence of primary incomes, replacement rates are not necessarily the best indicator of the impact of the taxbenefit system in this respect. To isolate the effects of the tax-benefit system on both work incentives and the degree of social protection for the out-of-work population, we therefore introduce a new measure, the tax-benefit-to-earnings ratio.European Union, Microsimulation, Net Replacement Rate, Unemployment Benefits, Work Incentives
Two new pulsating hot subdwarf stars from the Edinburgh-Cape survey
We report the discovery of very rapid pulsations in two hot subdwarf stars from the Edinburgh-
Cape blue object survey. The short periods, small amplitudes and multiperiodicity establish
these stars as members of the class of rapidly-pulsating sdB stars. The spectrograms of
both stars, however, show relatively strong He II 4686 and they are therefore more properly
classified as sdOB. The light curve of EC 01541?1409 is dominated by two strong
(?1 per cent) variations with frequencies near 7114 and 7870 ?Hz (periods near 140.6 and
127.1 s), though at least five frequencies are present with amplitudes above about 0.002 mag.
The light curve of EC 22221?3152 appears to be generated by at least 10 frequencies in the
range 5670-11850 ?Hz (about 175-85 s) with amplitudes between about 0.01 and 0.001 mag,
including the first overtone of the strongest variation. Somewhat surprisingly, this number of
frequencies is detectable in observing runs as short as 3 h, probably due to the fact that the
detected frequencies are well-separated.IS
Hot subdwarf stars in close-up view IV. Helium abundances and the 3He isotopic anomaly of subdwarf B stars
Atmospheric parameters and helium abundances of 44 bright subdwarf B stars have been determined. More than half of our sample
consists of newly discovered stars from the Edinburgh Cape survey. We showed that effective temperatures and surface gravities can
be derived from high resolution echelle spectra with sufficient accuracy. Systematic uncertainties have been determined by comparing
the parameters derived from the high resolution data with the ones derived from medium resolution spectra. Helium abundances have
been measured with high accuracy. Besides the known correlation of helium abundance with temperature, two distinct sequences in
helium abundance have been confirmed. Significant isotopic shifts of helium lines due to an enrichment in 3He have been found in
the spectra of 8 subluminous B stars (sdBs). Most of these stars cluster in a small temperature range between 27 000K and 31 000K
very similar to the known 3He-rich main sequence B stars, which also cluster in such a small strip, but at different temperatures. Both
the helium sequences and the isotopic anomaly are discussed.Web of Scienc
Whole Earth Telescope observations of the hot helium atmosphere pulsating white dwarf EC 20058-5234
We present the analysis of a total of 177h of high-quality optical
time-series photometry of the helium atmosphere pulsating white dwarf (DBV) EC
20058-5234. The bulk of the observations (135h) were obtained during a WET
campaign (XCOV15) in July 1997 that featured coordinated observing from 4
southern observatory sites over an 8-day period. The remaining data (42h) were
obtained in June 2004 at Mt John Observatory in NZ over a one-week observing
period. This work significantly extends the discovery observations of this
low-amplitude (few percent) pulsator by increasing the number of detected
frequencies from 8 to 18, and employs a simulation procedure to confirm the
reality of these frequencies to a high level of significance (1 in 1000). The
nature of the observed pulsation spectrum precludes identification of unique
pulsation mode properties using any clearly discernable trends. However, we
have used a global modelling procedure employing genetic algorithm techniques
to identify the n, l values of 8 pulsation modes, and thereby obtain
asteroseismic measurements of several model parameters, including the stellar
mass (0.55 M_sun) and T_eff (~28200 K). These values are consistent with those
derived from published spectral fitting: T_eff ~ 28400 K and log g ~ 7.86. We
also present persuasive evidence from apparent rotational mode splitting for
two of the modes that indicates this compact object is a relatively rapid
rotator with a period of 2h. In direct analogy with the corresponding
properties of the hydrogen (DAV) atmosphere pulsators, the stable low-amplitude
pulsation behaviour of EC 20058 is entirely consistent with its inferred
effective temperature, which indicates it is close to the blue edge of the DBV
instability strip. (abridged)Comment: 19 pages, 8 figures, 5 tables, MNRAS accepte
The Hââș ionosphere of Uranus: decades-long cooling and local-time morphology
The upper atmosphere of Uranus has been observed to be slowly cooling between 1993 and 2011. New analysis of near-infrared observations of emission from Hââș obtained between 2012 and 2018 reveals that this cooling trend has continued, showing that the upper atmosphere has cooled for 27 years, longer than the length of a nominal season of 21 years. The new observations have offered greater spatial resolution and higher sensitivity than previous ones, enabling the characterization of the Hââș intensity as a function of local time. These profiles peak between 13 and 15âh local time, later than models suggest. The NASA Infrared Telescope Facility iSHELL instrument also provides the detection of a bright Hââș signal on 16 October 2016, rotating into view from the dawn sector. This feature is consistent with an auroral signal, but is the only of its kind present in this comprehensive dataset
Global upper-atmospheric heating on Jupiter by the polar aurorae
Jupiter's upper atmosphere is considerably hotter than expected from the amount of sunlight that it receives1-3. Processes that couple the magnetosphere to the atmosphere give rise to intense auroral emissions and enormous deposition of energy in the magnetic polar regions, so it has been presumed that redistribution of this energy could heat the rest of the planet4-6. Instead, most thermospheric global circulation models demonstrate that auroral energy is trapped at high latitudes by the strong winds on this rapidly rotating planet3,5,7-10. Consequently, other possible heat sources have continued to be studied, such as heating by gravity waves and acoustic waves emanating from the lower atmosphere2,11-13. Each mechanism would imprint a unique signature on the global Jovian temperature gradients, thus revealing the dominant heat source, but a lack of planet-wide, high-resolution data has meant that these gradients have not been determined. Here we report infrared spectroscopy of Jupiter with a spatial resolution of 2 degrees in longitude and latitude, extending from pole to equator. We find that temperatures decrease steadily from the auroral polar regions to the equator. Furthermore, during a period of enhanced activity possibly driven by a solar wind compression, a high-temperature planetary-scale structure was observed that may be propagating from the aurora. These observations indicate that Jupiter's upper atmosphere is predominantly heated by the redistribution of auroral energy.80NSSC19K0546 - Intramural NASAPublished versio
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