1,467 research outputs found

    Die Zahl der Maturanden zu senken, ist ein Unsinn

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    Welfare regimes and change in the employment structure: Britain, Denmark and Germany since 1990

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    Welfare states are often reduced to their role as providers of social protection and redistribution. In 1990, Esping-Andersen argued that they also affect employment creation and the class structure. We analyse the stratification outcomes for three welfare regimes - Britain, Germany and Denmark - over the 1990s and 2000s. Based on individual-level surveys, we observe a disproportionate increase among professionals and managers, and a decline among production workers and clerks. The result is clear-cut occupational upgrading in Denmark and Germany. In Britain, high and low-end service jobs expanded, resulting in a polarized version of upgrading. Growth in low-end service jobs - and thus polarization - is no precondition for full employment. Both Britain and Denmark halved their low-educated unemployment rate between 1995 and 2008. Yet low-end service jobs expanded only in Britain, not in Denmark. The cause is the evolution of labour supply: rising educational attainment means that fewer low-educated workers look for low-skilled jobs

    Quelles perspectives d'emploi et de salaire après un apprentissage

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    Nous analysons si les avantages d'un apprentissage à court terme, dus à une bonne intégration dans le marché du travail, se maintiennent au long du parcours de vie. Un apprentissage prépare bien les jeunes pour le début de leur carrière. Cependant, les compétences liées à un métier spécifique, apprises avant l'âge de 20 ans, peuvent se révéler obsolètes à l'âge de 45 ans. Nous comparons ainsi l'évolution de l'emploi et des salaires pour un apprentissage avec celle pour une maturité. Nos résultats se basent sur l'Enquête suisse sur la population active 1991-2014 et montrent que les travailleurs au bénéfice d'un apprentissage ne sont pas pris de vitesse par le changement technologique. Pour tous les âges, les taux de chômage et d'inactivité sont bas parmi les personnes avec un apprentissage - et leur taux d'emploi reste élevé au-delà de l'âge de 50 ans. Le bilan est toutefois moins rose au niveau des salaires. Si un apprentissage facilite le départ sur le marché du travail, une maturité donne lieu à une progression salariale au long du parcours de vie nettement supérieure. A partir de l'âge de 30 ans, les travailleurs n'ayant qu'une maturité - et donc pas de formation tertiaire - gagnent des salaires annuels plus élevés que ceux ayant effectué un apprentissage. L'avantage salarial en faveur de la maturité est particulièrement marqué pour les femmes

    Beschäftigungs- und Lohnperspektiven nach einer Berufslehre

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    Eine Berufslehre erleichtert den Einstieg in den Arbeitsmarkt. Wir analysieren, ob der sich daraus ergebende kurzfristige Vorteil auch im weiteren Lebenslauf erhalten bleibt. Eine Lehre bereitet Jugendliche gut auf den Beginn ihres Berufslaufbahn vor. Doch vor dem 20 Altersjahr erworbene, mit einem bestimmten Beruf verbundene Kompetenzen können sich bei einem 45jährigen als obsolet erweisen. Wir vergleichen deshalb die Entwicklung der Erwerbsbeteilung und der Löhne nach einer Berufslehre mit derjenigen nach einer Matura. Unsere Ergebnisse beruhen auf der Schweizerischen Arbeitskräfteerhebung 1991-2014 und zeigen, dass Personen mit einer Berufslehre nicht vom technologischen Wandel überrollt werden. In allen Altersgruppen sind die Arbeitslosenquote und der Anteil der Nichterwerbstätigen unter den Personen mit einem Lehrabschluss niedrig. Weniger rosig sieht die Bilanz jedoch bei den Löhnen aus. Zwar erleichtert eine Lehre den Einstieg in den Arbeitsmarkt, aber eine Matura führt zu einem deutlich stärkeren Lohnanstieg im Lauf des Erwerbskarriere. Vom 30. Altersjahr an verdienen Beschäftigte, die nur über eine Matura - und somit über keine tertiäre Ausbildung - verfügen, höhere Jahreslöhne als diejenigen, welche eine Berufslehre absolviert haben. Dieser Lohnvorteil für die Maturität zeigt sich besonders stark bei Frauen

    Expanded Search for z~10 Galaxies from HUDF09, ERS, and CANDELS Data: Evidence for Accelerated Evolution at z>8?

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    We search for z~10 galaxies over ~160 arcmin^2 of WFC3/IR data in the Chandra Deep Field South, using the public HUDF09, ERS, and CANDELS surveys, that reach to 5sigma depths ranging from 26.9 to 29.4 in H_160 AB mag. z>~9.5 galaxy candidates are identified via J_125-H_160>1.2 colors and non-detections in any band blueward of J_125. Spitzer IRAC photometry is key for separating the genuine high-z candidates from intermediate redshift (z~2-4) galaxies with evolved or heavily dust obscured stellar populations. After removing 16 sources of intermediate brightness (H_160~24-26 mag) with strong IRAC detections, we only find one plausible z~10 galaxy candidate in the whole data set, previously reported in Bouwens et al. (2011). The newer data cover a 3x larger area and provide much stronger constraints on the evolution of the UV luminosity function (LF). If the evolution of the z~4-8 LFs is extrapolated to z~10, six z~10 galaxies are expected in our data. The detection of only one source suggests that the UV LF evolves at an accelerated rate before z~8. The luminosity density is found to increase by more than an order of magnitude in only 170 Myr from z~10 to z~8. This increase is >=4x larger than expected from the lower redshift extrapolation of the UV LF. We are thus likely witnessing the first rapid build-up of galaxies in the heart of cosmic reionization. Future deep HST WFC3/IR data, reaching to well beyond 29 mag, can enable a more robust quantification of the accelerated evolution around z~10.Comment: 13 pages, 11 figures, ApJ resubmitted after referee repor

    Extremely Small Sizes for Faint z~2-8 Galaxies in the Hubble Frontier Fields: A Key Input For Establishing their Volume Density and UV Emissivity

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    We provide the first observational constraints on the sizes of the faintest galaxies lensed by the Hubble Frontier Fields (HFF) clusters. Ionizing radiation from faint galaxies likely drives cosmic reionization, and the HFF initiative provides a key opportunity to find such galaxies. Yet, we cannot really assess their ionizing emissivity without a robust measurement of their sizes, since this is key to quantifying both their prevalence and the faint-end slope to the UV luminosity function. Here we provide the first such size constraints with 2 new techniques. The first utilizes the fact that the detectability of highly-magnified galaxies as a function of shear is very dependent on a galaxy's size. Only the most compact galaxies will remain detectable in regions of high shear (vs. a larger detectable size range for low shear), a phenomenon we carefully quantify using simulations. Remarkably, however, no correlation is found between the surface density of faint galaxies and the predicted shear, using 87 faint high-magnification mu>10 z~2-8 galaxies seen behind the first 4 HFF clusters. This can only be the case if such faint (~-15 mag) galaxies have significantly smaller sizes than luminous galaxies. We constrain their half-light radii to be <~30 mas (<160-240 pc). As a 2nd size probe, we rotate and stack 26 faint high-magnification sources along the major shear axis. Less elongation is found than even for objects with an intrinsic half-light radius of 10 mas. Together these results indicate that extremely faint z~2-8 galaxies have near point-source profiles in the HFF dataset (half-light radii conservatively <30 mas and likely 5-10 mas). These results suggest smaller completeness corrections and hence much lower volume densities for faint z~2-8 galaxies and shallower faint-end slopes than have been derived in many recent studies (by factors of ~2-3 and by dalpha>~0.1-0.3).Comment: 19 pages, 15 figures, 3 tables, accepted for publication in Ap

    The Dearth of z~10 Galaxies in all HST Legacy Fields -- The Rapid Evolution of the Galaxy Population in the First 500 Myr

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    We present an analysis of all prime HST legacy fields spanning >800 arcmin^2 for the search of z~10 galaxy candidates and the study of their UV luminosity function (LF). In particular, we present new z~10 candidates selected from the full Hubble Frontier Field (HFF) dataset. Despite the addition of these new fields, we find a low abundance of z~10 candidates with only 9 reliable sources identified in all prime HST datasets that include the HUDF09/12, the HUDF/XDF, all the CANDELS fields, and now the HFF survey. Based on this comprehensive search, we find that the UV luminosity function decreases by one order of magnitude from z~8 to z~10 at all luminosities over a four magnitude range. This also implies a decrease of the cosmic star-formation rate density by an order of magnitude within 170 Myr from z~8 to z~10. We show that this accelerated evolution compared to lower redshift can entirely be explained by the fast build-up of the dark matter halo mass function at z>8. Consequently, the predicted UV LFs from several models of galaxy formation are in good agreement with this observed trend, even though the measured UV LF lies at the low end of model predictions. In particular, the number of only 9 observed candidate galaxies is lower, by ~50%, than predicted by galaxy evolution models. The difference is generally still consistent within the Poisson and cosmic variance uncertainties. However, essentially all models predict larger numbers than observed. We discuss the implications of these results in light of the upcoming James Webb Space Telescope mission, which is poised to find much larger samples of z~10 galaxies as well as their progenitors at less than 400 Myr after the Big Bang.Comment: 13 pages, 6 figures, minor updates to match accepted versio

    Very blue UV-continuum slopes of low luminosity z~7 galaxies from WFC3/IR: Evidence for extremely low metallicities?

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    We use the ultra-deep WFC3/IR data over the HUDF and the Early Release Science WFC3/IR data over the CDF-South GOODS field to quantify the broadband spectral properties of candidate star-forming galaxies at z~7. We determine the UV-continuum slope beta in these galaxies, and compare the slopes with galaxies at later times to measure the evolution in beta. For luminous L*(z=3) galaxies, we measure a mean UV-continuum slope beta of -2.0+/-0.2, which is comparable to the beta~-2 derived at similar luminosities at z~5-6. However, for the lower luminosity 0.1L*(z=3) galaxies, we measure a mean beta of -3.0+/-0.2. This is substantially bluer than is found for similar luminosity galaxies at z~4, just 800 Myr later, and even at z~5-6. In principle, the observed beta of -3.0 can be matched by a very young, dust-free stellar population, but when nebular emission is included the expected beta becomes >~-2.7. To produce these very blue beta's (i.e., beta~-3), extremely low metallicities and mechanisms to reduce the red nebular emission are likely required. For example, a large escape fraction (i.e., f_{esc}>~0.3) could minimize the contribution from this red nebular emission. If this is correct and the escape fraction in faint z~7 galaxies is >~0.3, it may help to explain how galaxies reionize the universe.Comment: 5 pages, 5 figures, accepted for publication in Astrophysical Journal Letter
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