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  • Oxford University Press  (7)
  • ZBW - Deutsche Zentralbibliothek für Wirtschaftswissenschaften, Leibniz-Informationszentrum Wirtschaft Kiel, Hamburg  (3)
  • Cambridge University Press  (2)
  • 1
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    Berlin: Deutsches Institut für Wirtschaftsforschung (DIW) | ZBW - Deutsche Zentralbibliothek für Wirtschaftswissenschaften, Leibniz-Informationszentrum Wirtschaft Kiel, Hamburg
    Publication Date: 2018-01-25
    Description: The paper presents results for the development of total factor productivity (TFP) growth for 35 industries. It analyses the medium-term and long-term trends in these industries during the last two decades. The method used for the calculation was first proposed by Hulten (1986). It takes into account capacity utilization effects for the capital stock. Comparing the average TFP growth rates for manufacturing before, during, and after the two oil price shocks one observes that there is a steady acceleration from a fairly low 1.4 per cent rate during 1970-74 to 2 per cent during 1984-89. Contrary labour productivity, measured by annual working hours, declined. Therefore the increase in TFP growth rates has to be attributed to a marked shift in capital productivity. During the early 70ies capital productivity growth rates were negative in manufacturing supporting a hypothesis of capital using and labour saving technological progress. Since then capital productivity became positive across all major subindustries in manufacturing. This led to the up-tum in TFP growth. Four hypothesis are proposed in the paper to explain the shift in the development of capital productivity growth. In the last section a number of cross-section regressions for the 35 industries for the whole period as well as a number of subperiods are calculated. As the results show Verdooms Law seems to be valid for all periods considered. Therefore high growth industries are - with respect to gross value added - leading industries in high TFP growth as well
    Keywords: D24 ; ddc:330
    Repository Name: EconStor: OA server of the German National Library of Economics - Leibniz Information Centre for Economics
    Language: English
    Type: doc-type:workingPaper
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  • 2
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    Unknown
    Berlin: Duncker & Humblot | ZBW - Deutsche Zentralbibliothek für Wirtschaftswissenschaften, Leibniz-Informationszentrum Wirtschaft Kiel, Hamburg
    Publication Date: 2018-01-25
    Keywords: ddc:330 ; Wettbewerbspolitik ; Industrieökonomik ; Deutschland
    Repository Name: EconStor: OA server of the German National Library of Economics - Leibniz Information Centre for Economics
    Language: German
    Type: doc-type:article
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  • 3
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    Berlin: Deutsches Institut für Wirtschaftsforschung (DIW) | ZBW - Deutsche Zentralbibliothek für Wirtschaftswissenschaften, Leibniz-Informationszentrum Wirtschaft Kiel, Hamburg
    Publication Date: 2018-01-25
    Description: The paper presents results for the development of total factor productivity (TFP) growth for 35 industries. It analyses the medium-term and long-term trends in these industries during the last two decades. The method used for the calculation was first proposed by Huiten (J986). It takes into account capacity utilization effects for the capital stock. Comparing the average TFP growth rates for manufacturing before, during, and after the two oil price shocks one observes that there is a steady acceleration from a fairly low 1.4per cent rate during 1970-74 to 2 per cent during 1984-89. Contrary labour productivity, measured by annual working hours, declined. Therefore the increase in TFP growth rates has to be attributed to a marked shift in capital productivity. During the early 70ies capital productivity growth rates were negative in manufacturing supporting a hypothesis of capital using and labour saving technological progress. Since then capital productivity became positive across all major subindustries in manufacturing. This led to the up-turn in TFP growth. Four hypothesis are proposed in the paper to explain the shift in the development of capital productivity growth. In the last section a number of cross-section regressions for the 35 industries for the whole period as well as a number of subperiods are calculated. As the results show Verdoorns Law seems to be valid for all periods considered Therefore high growth industries are - with respect to gross value added - leading industries in high TFP growth as well.
    Keywords: D24 ; ddc:330
    Repository Name: EconStor: OA server of the German National Library of Economics - Leibniz Information Centre for Economics
    Language: German
    Type: doc-type:workingPaper
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  • 4
    Publication Date: 2016-06-17
    Description: Supernova (SN) blast waves inject energy and momentum into the interstellar medium (ISM), control its turbulent multiphase structure and the launching of galactic outflows. Accurate modelling of the blast wave evolution is therefore essential for ISM and galaxy formation simulations. We present an efficient method to compute the input of momentum, thermal energy, and the velocity distribution of the shock-accelerated gas for ambient media (densities of 0.1 ≥ n 0 [cm – 3 ] ≥ 100) with uniform (and with stellar wind blown bubbles), power-law, and turbulent (Mach numbers $\mathcal {M}$ from 1to100) density distributions. Assuming solar metallicity cooling, the blast wave evolution is followed to the beginning of the momentum conserving snowplough phase. The model recovers previous results for uniform ambient media. The momentum injection in wind-blown bubbles depend on the swept-up mass and the efficiency of cooling, when the blast wave hits the wind shell. For power-law density distributions with n ( r ) ~  r –2 (for n ( r ) 〉  n floor ) the amount of momentum injection is solely regulated by the background density n floor and compares to n uni = n floor . However, in turbulent ambient media with lognormal density distributions the momentum input can increase by a factor of 2 (compared to the homogeneous case) for high Mach numbers. The average momentum boost can be approximated as $p_{{\rm turb}}/{p_{{0}}}\ =23.07\, \left(\frac{n_{{0,\rm turb}}}{1\,{\rm cm}^{-3}}\right)^{-0.12} + 0.82 (\ln (1+b^{2}\mathcal {M}^{2}))^{1.49}\left(\frac{n_{{0,\rm turb}}}{1\,{\rm cm}^{-3}}\right)^{-1.6}$ . The velocity distributions are broad as gas can be accelerated to high velocities in low-density channels. The model values agree with results from recent, computationally expensive, three-dimensional simulations of SN explosions in turbulent media.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
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  • 5
    Publication Date: 2015-03-22
    Description: We use hydrodynamical simulations in a (256 pc) 3 periodic box to model the impact of supernova (SN) explosions on the multiphase interstellar medium (ISM) for initial densities n  = 0.5–30 cm –3 and SN rates 1–720 Myr –1 . We include radiative cooling, diffuse heating, and the formation of molecular gas using a chemical network. The SNe explode either at random positions, at density peaks, or both. We further present a model combining thermal energy for resolved and momentum input for unresolved SNe. Random driving at high SN rates results in hot gas ( T   10 6  K) filling 〉90 per cent of the volume. This gas reaches high pressures (10 4  〈  P / k B  〈 10 7  K cm –3 ) due to the combination of SN explosions in the hot, low-density medium and confinement in the periodic box. These pressures move the gas from a two-phase equilibrium to the single-phase, cold branch of the cooling curve. The molecular hydrogen dominates the mass (〉50 per cent), residing in small, dense clumps. Such a model might resemble the dense ISM in high-redshift galaxies. Peak driving results in huge radiative losses, producing a filamentary ISM with virtually no hot gas, and a small molecular hydrogen mass fraction (〈〈1 per cent). Varying the ratio of peak to random SNe yields ISM properties in between the two extremes, with a sharp transition for equal contributions. The velocity dispersion in H i remains 10 km s –1 in all cases. For peak driving, the velocity dispersion in Hα can be as high as 70 km s –1 due to the contribution from young, embedded SN remnants.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
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  • 6
    Publication Date: 2015-01-29
    Description: The development of coastal polynyas, areas of enhanced heat flux and sea ice production strongly depend on atmospheric conditions. In Antarctica, measurements are scarce and models are essential for the investigation of polynyas. A robust quantification of polynya exchange processes in simulations relies on a realistic representation of atmospheric conditions in the forcing dataset. The sensitivity of simulated coastal polynyas in the south-western Weddell Sea to the atmospheric forcing is investigated with the Finite-Element Sea ice-Ocean Model (FESOM) using daily NCEP/NCAR reanalysis data (NCEP), 6 hourly Global Model Europe (GME) data and two different hourly datasets from the high-resolution Consortium for Small-Scale Modelling (COSMO) model. Results are compared for April to August in 2007–09. The two coarse-scale datasets often produce the extremes of the data range, while the finer-scale forcings yield results closer to the median. The GME experiment features the strongest winds and, therefore, the greatest polynya activity, especially over the eastern continental shelf. This results in higher volume and export of High Salinity Shelf Water than in the NCEP and COSMO runs. The largest discrepancies between simulations occur for 2008, probably due to differing representations of the ENSO pattern at high southern latitudes. The results suggest that the large-scale wind field is of primary importance for polynya development.
    Print ISSN: 0954-1020
    Electronic ISSN: 1365-2079
    Topics: Biology , Geography , Geosciences
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  • 7
    Publication Date: 2013-11-26
    Description: Mesoscale model simulations were conducted for the Weddell Sea region for the autumn and winter periods of 2008 using a high-resolution, limited-area, non-hydrostatic atmospheric model. A sea ice–ocean model was run with enhanced horizontal resolution and high-resolution forcing data of the atmospheric model. Daily passive thermal and microwave satellite data was used to derive the polynya area in the Weddell Sea region. The focus of the study is on the formation of polynyas in the coastal region of Coats Land, which is strongly affected by katabatic flows. The polynya areas deduced from two independent remote sensing methods and data sources show good agreement, while the results of the sea ice simulation show some weaknesses. Linkages between the pressure gradient force composed of a katabatic and a synoptic component, offshore wind regimes and polynya area are identified. It is shown that the downslope surface offshore wind component of Coats Land is the main forcing factor for polynya dynamics, which is mainly steered by the offshore pressure gradient force, where the katabatic force is the dominant term. We find that the synoptic pressure gradient is opposed to the katabatic force during major katabatic wind events.
    Print ISSN: 0954-1020
    Electronic ISSN: 1365-2079
    Topics: Biology , Geography , Geosciences
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  • 8
    Publication Date: 2019-12-19
    Description: We analyse the CO-dark molecular gas content of simulated molecular clouds from the SILCC-Zoom project. The simulations reach a resolution of 0.1 pc and include H2 and CO formation, radiative stellar feedback and magnetic fields. CO-dark gas is found in regions with local visual extinctions $A_ m {V, 3D} sim$ 0.2–1.5, number densities of 10–103 cm−3 and gas temperatures of few 10–100 K. CO-bright gas is found at number densities above 300 cm−3 and temperatures below 50 K. The CO-dark gas fractions range from 40 per cent to 95 per cent and scale inversely with the amount of well-shielded gas ($A_ m {V, 3D}$ ≳ 1.5), which is smaller in magnetized molecular clouds. We show that the density, chemical abundances and $A_ m {V, 3D}$ along a given line-of-sight cannot be properly determined from projected quantities. As an example, pixels with a projected visual extinction of $A_ m {V, 2D} simeq$ 2.5–5 can be both, CO-bright or CO-dark, which can be attributed to the presence or absence of strong density enhancements along the line-of-sight. By producing synthetic CO(1-0) emission maps of the simulations with RADMC-3D, we show that about 15–65 per cent of the H2 is in regions with intensities below the detection limit. Our clouds have $X_ m {CO}$-factors around 1.5 × 1020 cm−2 (K km s−1)−1 with a spread of up to a factor ∼ 4, implying a similar uncertainty in the derived total H2 masses and even worse for individual pixels. Based on our results, we suggest a new approach to determine the H2 mass, which relies on the availability of CO(1-0) emission and $A_ m {V, 2D}$ maps. It reduces the uncertainty of the clouds’ overall H2 mass to a factor of ≲ 1.8 and for individual pixels, i.e. on sub-pc scales, to a factor of ≲ 3.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
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  • 9
  • 10
    Publication Date: 2016-05-09
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
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